FIELD OF INVENTION

The present invention relates to reinforced concretes. In particular the present invention describes reinforced concretes manufactured with bamboo splints and bamboo fibres for use in construction industry.

BACKGROUND ART

Reinforcement of concrete structures has been studied by using steel reinforcement, fibrous reinforcement materials, or any other reinforcement materials. Steel reinforcement are steel bars which are usually used in the form of reinforcing bar or rebar as reinforcing steel or reinforcement steel. Such steel reinforcement is a steel bar or mesh of steel wires used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and assist the concrete under tension.] Fibrous reinforcements include synthetic and natural fibre. Besides synthetic fibres, other materials such as steel, glass and carbon in fibrous form have been used as concrete reinforcement along with concrete. Although these conventional materials provide significant improvement in the properties of concrete, they are obtained from nonrenewable and unsustainable sources which make them an environmentally irresponsible material. Considering the limitations of these conventional reinforcing materials, the focus has been to use renewable and sustainable material. These include natural fibres which contains lignocellulosic materials in their composition which possess the suitable strength and material characteristics.

In the present invention, bamboos are to be used as reinforcement for concrete to make reinforced concrete structures more sustainable and eco-friendly.

An example of composite concrete with bamboo structural members is disclosed in United States Patent No. US 7939156 B2 (hereinafter referred to as the US 156 Patent) entitled “Composite concrete/bamboo structure” having a filing date of 22 June 2009 (Applicant: Slaven, Jr. Leland and Bernhard Robert). The US 156 Patent divulges composite concrete with bamboo structural members. The bamboo material includes layers formed of bamboo segments which have been dried and glue coated. The segments are substantially free of outer nodes and husk and inner membrane material prior to application of glue. The longitudinal axes of the segments in each layer are generally parallel to one another and are arranged in a mould to surround the surface of a cured concrete core. The layers of segments are heated, compressed and bonded together until the glue cures around the concrete core into a single integral structure. The concrete core of the US 156 Patent is preferably reinforced with steel REBAR rods.

Another example of concrete mixture incorporating bamboo fibres is disclosed in Chinese Patent Application No. CN 107814540 (CN 540 Patent) entitled “ Fibre toughening sprayed concrete” having a filing date of 20 March 2018 (Applicant: UNIVERSITY JINAN). The CN 540 Patent provides a fibre toughened shotcrete which is composed of cement, fly ash, fine aggregates, coarse aggregates, bamboo fibre filament, water reducing agent, viscosity adjusting component and quick setting agent. The CN 540 Patent discloses the addition of bamboo fibres to the concrete to enhance the toughness of the concrete and to improve mechanical properties. The bamboo filaments utilized in The CN 540 Patent were provided in a length of 5 to 10 mm and were added to the concrete mixture within the range of 50 to 80 w/v.

An example of bamboo arrangement of reinforcement concrete structure is disclosed in Patent Application No. CN 207419847 (CN 847Patent) entitled “Bamboo timber arrangement of reinforcement concrete structure” having a filing date 29 May 2018 (Applicant: UNIVERSITY NANJING FORESTRY). The CN 847 Patent provides bamboo reinforced concrete comprising of longitudinal bamboo ribs, bamboo stirrups, fibre bundles, the longitudinal bamboo ribs longitudinally arranged along the axis of the member and bamboo stirrups arranged perpendicularly to the bamboo ribs. The core of the longitudinal bamboo ribs and the bamboo stirrups are provided with anti-corrosion reinforced layer. The bamboo ribs are provided in concave- convex structure. The anti-corrosion reinforced layer of The CN 847 Patent is composed of fibre reinforced composite material and adhered with gravel. The longitudinal bamboo ribs and bamboo stirrups forms bamboo skeleton and concrete were poured around the bamboo skeleton to form the bamboo reinforced concrete structure. The CN 847 Patent provides the addition of bamboo to overcome the shortcomings of existing reinforced concrete and common bamboo reinforced concrete structure. Although the above-mentioned prior arts provide various features and enhancements over concrete steel reinforcements, there is a continued need to include sustainable capacities in construction and building materials. Hence, the present invention utilises bamboos as alternative material to steel reinforcement in construction and building materials.

SUMMARY OF INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as prelude to the more detailed description that is presented later.

One aspect of the invention provides a bamboo reinforced concrete beam (100). The bamboo reinforced concrete beam comprising a plurality of bamboo splints forming a top (102) and bottom (104) reinforcement; a plurality shear links for shear reinforcement (106);concrete; and a plurality of steel wires for joining the plurality of bamboo splints. The plurality of bamboo splints (102,104) and the plurality of shear links (106) are fabricated from bamboos which are chemically treated with a combination of alkaline solution to mitigate fungus growth and black oxide primer to provide water repellent properties and to protect the bamboo splints against insect infestation.

Another aspect of the invention provides that the bamboo splints (102, 104) are fabricated from bamboo in the maturity age of at least 4 to 5 years.

The alkaline solution used as chemical treatment is sodium hydroxide, NaOH.

The concrete is entirely free from any admixtures.

The plurality of steel wires provides at least 2 cm space in between the plurality of bamboo splints (102,104). Another aspect of the invention provides a bamboo fibre reinforced concrete beam. The bamboo fibre reinforced concrete beam comprising chemically treated bamboo fibres; cement mix; fine aggregates; coarse aggregates; and water. The bamboo fibres are extracted from plurality of bamboo splints which are chemically treated with a combination of alkaline solution to mitigate fungus growth. The alkaline solution used as chemical treatment in the bamboo fibre reinforced concrete beam is sodium hydroxide, NaOH.

The cement is a non-composite ordinary Portland cement without any admixtures.

The fine aggregates are river sand with the size not more than 4.75mm in size. The coarse aggregates are in a combination of 10mm and 20mm in size.

The size of the 10 mm coarse aggregate and 20mm coarse aggregate is at a ratio of 1 :2.

The chemically treated bamboo fibres are at a maximum length of 1.5 inch.

The bamboo fibres are at least 2%.

Another aspect of the invention provides a method for manufacturing bamboo fibre reinforced concrete (200) beam comprising steps of preparing bamboo fibres (202); mixing cement, fine aggregates, coarse aggregates, water and bamboo fibres to form a concrete mixture (204); casting the concrete mixture (206); and curing the concrete mixture (208). The step of preparing bamboo fibres further comprises steps of soaking a plurality of bamboo splints in 2.5 M alkaline solution for at least 24 hr in ambient temperature (202a); defibrating the plurality bamboo splints to obtain bamboo fibres (202b); rinsing bamboo fibres in distilled water until pH value of the bamboo fibres fall within pH 6.5 to pH 7.5 (202c); drying the bamboo fibres at 60°Cfor at least 24 hr (202d); and storing the bamboo fibres in vacuum desiccators with silica gel to prevent moisture absorption (202e).

Still another aspect of the invention provides a use of bamboo reinforced concrete and bamboo fibre reinforced concrete as a support system in a build of telecommunication sites.

The present invention consists of features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings, it is being understood that various changes in the details may be made without departing the scope of the invention or sacrificing any of the advantages of the present invention. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

To further clarify various aspects of some embodiments of the present invention, a more particular description of the invention will be rendered by references to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the accompanying drawings.

FIGS. 1.1 and 1.2 illustrate schematic diagram of the bamboo reinforced concrete beam of the present invention. FIG. 1.3 illustrates the different bamboo species studied in the present invention to determine the most suitable type for use as bamboo reinforcement concrete beam, BRC and bamboo reinforcement fiber concrete, BRFC.

FIG. 1.4 illustrates the steps in the process of manufacturing bamboo fibre reinforced concrete of the present invention. FIG. 1 .5 illustrates steps involved in preparing bamboo fibres of the present invention.

FIG. 2.1 illustrates the compression test of untreated bamboo carried out according to the present invention.

FIG. 2.2 illustrates the tensile test of untreated bamboo carried out according to the present invention. FIG. 2.3 illustrates the sample preparation for water absorption test according to the present invention.

FIG. 2.4 illustrates the compression test of treated and untreated bamboo samples according to the present invention.

FIG. 2.5 illustrates the tensile test of treated and untreated bamboo samples according to the present invention. FIG. 2.6 illustrates the BRC age weathering test according to the present invention.

FIG. 2.7 illustrates a photograph of bamboo stacked horizontally for air-drying according to the present invention.

FIG. 2.8 illustrates the process of splitting the bamboo according to the present invention. FIG. 2.9 illustrates the process of chemical treatment with sodium hydroxide, sun drying and black oxide primer used to protect the bamboo against insect infestation according to the present invention.

FIG. 2.10 (a) illustrates the process before concrete casting whereby grease is applied to concrete cube moulds. FIG. 2.10(b) illustrates bamboo reinforcement beam in a greased formwork.

FIGS. 2.11 (a) - (c) illustrate the process of beam casting and curing.

FIGS. 2.12 (a) - (c) illustrate the beam testing via slum test, compression test and four-point loading test.

FIG. 2.13 illustrates the process of extracting bamboo fibres according to the present invention.

FIG. 2.14 illustrates the testing of weathered bamboo fibre reinforced concrete, BFRC specimens, beam.

FIG. 2.15 illustrates the compression strength test of the bamboo fibre reinforced concrete specimens, beam. FIG. 2.16 illustrates the flexural strength test of bamboo fibre reinforced concrete specimens, beam.

FIG. 2.17 illustrates the structural test of bamboo fibre reinforced concrete specimens, beam by utilizing four-point loading machine. FIG. 3.1 is a stress- strain curve of Betong under compression according to the present invention.

FIG. 3.2 is a stress- strain curve of Semantan under compression according to the present invention. FIG. 3.3 is a stress- strain curve of Beting under compression according to the present invention.

FIGS. 3.4 (a), (b) and (c) illustrates the cracking pattern of Betong, Semantan and Beting according to the present invention.

FIG. 3.5 is a stress- strain curve of Betong under tensile load according to the present invention.

FIG. 3.6 is a stress- strain curve of Semantan under tensile load according to the present invention

FIG. 3.7 is a stress- strain curve of Beting under tensile load according to the present invention FIGS. 3.8(a) to 3.8(c) illustrate the failure pattern of Betong, Semantan and Beting splint at node under tensile load.

FIG. 3.9 is a stress- strain curve comparing Betong, Semantan and Beting under compression according to the present invention.

FIG. 3.10 is a stress- strain curve comparing Betong, Semantan and Beting under tension according to the present invention.

FIG. 3.11 is a stress- strain curve of thermal decomposition of Betong, Semantan and Beting according to the present invention.

FIG. 3.12 is a comparison stress- strain curve between steel bar and Betong, Semantan and Beting according to the present invention. FIG. 4.1 illustrates the graph of the amount of water absorbed versus number of soaking days.

FIG. 4.2 illustrates the relationship between amounts of water absorbed versus number of nodes. FIG. 4.3 illustrates the thermal decomposition pattern of the treated bamboo.

FIG. 4.4 illustrates the stress-strain curve of compression test for untreated raw and dried samples as well as the bamboo treated with NaOH and Oxide Primer.

FIG. 4.5 illustrates the stress - strain curve of tensile test of bamboo samples for untreated raw and dried samples as well as the bamboo treated with NaOH and Oxide Primer. FIG. 4.6 illustrates the stress-strain curve of compression test of bamboo samples.

FIG. 4.7 illustrates the load-deflection curve of the control beams, steel reinforced tested at 14 days of curing.

FIG. 4.8 illustrates the load-deflection behaviour curve of BRC beam with NaOH + oxide primer tested at 14 days of curing. FIG. 4.9 illustrates comparison of the load-deflection curve between BRC with NaOH + oxide primer and control beams tested at 14 days of curing.

FIG. 4.10 illustrates the crack pattern of the control beam reinforced by iron bar.

FIG. 4.11 illustrates the crack pattern of BRC beams treated with sodium hydroxide and oxide primer. FIG. 4.12 shows the comparison of load-deflection curves of the control beams after 28 days of curing.

FIG. 4.13 shows the load deflection behaviour comparison of BRC beams with bamboo treated with NaOH without oxide primer tested at 14 days of curing. FIG. 4.14 shows the load deflection behaviour comparison of three BRC beams with bamboo treated with NaOH and coated with oxide primer and respectively tested at 14 days of curing.

FIG. 4.15 shows the load deflection comparison of control beam, BRC beam treated with NaoFI and treated with NaOH and oxide primer. FIG. 4.16 shows the crack pattern of control beams reinforced by iron bar.

FIG. 4.17 shows the crack pattern of BRC beams treated with NaOH .

FIG. 4.18 shows the crack pattern of BRC beams treated with NaOH + Oxide Primer.

FIG. 4.19 shows the graph of load versus deflection of weathered BRC using bamboo treated either with NaOH only, control or NaOH and OP, BRC and OP specimens. FIG. 4.20 shows the graph comparison of the weathered specimens of the control BRC and BRC with OP in terms of load versus deflection.

FIG. 4.21 illustrates a graph comparing the weathered and unweathered specimens of control BRC.

FIG. 4.22 illustrates a graph comparing the weathered and unweathered specimens of BRC + OP specimens.

FIG. 4.23 shows the crack pattern or weathered BRC1 and BRC2 specimens.

FIG. 4.24 shows the crack pattern of weathered BRC specimens coated with oxide primer.

FIG. 4.25 shows the crack pattern of unweathered conditions of control BRC.

FIG. 4.26 shows the crack pattern of unweathered conditions of specimen (a) BRC+OP1 and (b) BRC+OP2.

FIG. 5.1 illustrates the slump result of the fresh properties of the control concrete mix and the bamboo fibre reinforced concrete mix. FIG. 5.2 shows the comparison of slump value for each mixes.

FIG. 5.3 shows the comparison of control mix, plain concrete with respect to 1 inch to 2.5 inches of 1% bamboo fibre in concrete at curing age of 14 days.

FIG. 5.4 shows the compressive strength result of various percentages of fibre in concrete, 1 %, 1 .25%, 1.5% and 2% with the selected fibre length of 1 .5 inches.

FIG. 5.5 shows the comparison of compressive strength vs curing age of various bamboo fiber lengths in concrete.

FIG. 5.6 shows the comparison of compressive strength vs curing age of various bamboo fiber percentage. FIG. 5.7 shows failure pattern (a) plain concrete and (b) BFRC mix.

FIG. 5.8 shows the comparison of Flexural strength vs. curing age of various bamboo fiber lengths.

FIG. 5.9 shows the compressive strength result of various percentages of fibre in concrete, 1%, 1 .25%, 1.5% and 2% with the selected fibre length of 1 .5 inches. FIG. 5.10 shows the comparison of flexural strength vs curing age of various fiber lengths.

FIG. 5.11 shows the comparison of Flexural strength vs curing age of various fiber percentages with the selected fibre length of 1 .5 inches.

FIG. 5.12 shows an image of failure mechanism of plain concrete beam.

FIG. 5.13 shows an image of failure mechanism of BFRC concrete beam. FIG. 5.14 shows an image of slump of control mix from the slump test.

FIG. 5.15 shows an image of slump of 2% BFRC mix from the slump test. FIG. 5.16 illustrates a graph of the compressive strength of control mix without fiber and 2% fiber with 1.5-inch length BFRC mix concrete versus curing age at 3, 7, 14 and 28 days.

FIG. 5.17 illustrates a graph of comparison of load-deflection curve of Control beam 1 and BFRC fiber 1 . FIG. 5.18 illustrates a graph of comparison of load-deflection curve of Control beam2 and BFRC fiber 2.

FIG. 5.19 shows an image of the crack pattern of control beam.

FIG. 5.20 shows an image of the Crack pattern of 2% BFRC beam.

FIG. 5.21 illustrates a graph of load vs deflection of weathered and unweathered BFRC specimens.

FIG. 5.22 shows an image of the crack pattern of weathered and unweathered BFRC specimens.

DETAILED DESCRIPTION

The present invention relates to reinforced concretes. In particular the present invention describes reinforced concretes manufactured with bamboo splints and bamboo fibers for use in construction industry. Bamboos are desirable sustainable replacements for reinforcing concrete structures due to its versatility, renewability and tensile properties. Although most abundantly found in most tropical and subtropical region, bamboos are not fully utilized as alternative reinforcements to steel reinforcements in structural concrete.

The present invention discloses reinforced concretes utilizing bamboos splints and fibres with enhance structural robustness. FIGS. 1.1 and 1.2 illustrate schematic diagram of the bamboo reinforced concrete beam of the present invention (100). Three types of bamboo species namely Betong, Beting and Semantan as shown in FIG. 1.3 were tested to determine the most suitable type for use as bamboo reinforcement concrete beam, BRC and bamboo fiber reinforced concrete, BFRC. hereinafter, this specification will describe the present invention according to the preferred embodiments. It is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned without departing from the scope of the appended claims.

The present invention discloses a bamboo reinforced concrete beam composition. The bamboo reinforced concrete beam composition comprises; a plurality of bamboo splints forming a top (102) and bottom (104) reinforcement, a plurality of shear links for shear reinforcements (106), concrete and a plurality of steel wires for joining the bamboo splints. The plurality of bamboo splints (102,104) and shear links (106) are fabricated from Semantan bamboo species and are chemically treated with alkaline solution and black oxide primer. The concrete is devoid of any admixtures. The bamboo splints are fabricated from bamboo in the maturity age of at least 4 to 5 years and having diameter within the range of at least 80 to 90 mm. The plurality of bamboo splints and shear links are treated with alkaline solution to mitigate fungus growth. The alkaline solution used as chemical treatment is sodium hydroxide, NaOH. Then, the plurality of bamboo splints and shear links were coated with black oxide primer to provide water repellent effects to prolong the lifespan of the structure and to protect the splints and links against insect infestation. The bamboo splints are tied with steel wires by providing at least 2 cm space in between the plurality of bamboo splints (102, 104) for enhanced strength. Three (3) bamboo splints were tied as top (102) and bottom (104) reinforcements. The shear links were made of bamboo splints that cut into at least 120 mm length. A fastening means such as a screw was used to create the inter-splint gap. The beams were casted in wooden formworks using ready-mixed concrete of grade 30 MPa without admixture such that the concrete is entirely free from any admixtures. After concrete casting, the beams were covered using a polyethylene sheet for 24 hours to prevent hydration. All the beams were cured using wetted gunny bags.

The present invention further discloses a bamboo fibre reinforced concrete beam comprising chemically treated bamboo fibres, cement, fine aggregates, coarse aggregates and water. The bamboo fibres are extracted from a plurality of Semantan bamboo splints which are chemically treated with a combination of alkaline solution. The bamboo splints are treated with alkaline solution to mitigate fungus growth. The alkaline solution used as chemical treatment in the bamboo fibre reinforced concrete beam is sodium hydroxide, NaOH. The cement is non-composite ordinary Portland cement without any admixtures. The fine aggregates are river sand are not more than 4.75mm.

The coarse aggregates are in a combination of 10mm and 20mm in size. The ratio of the 10mm sized aggregates to the 20mm sized aggregates is 1 :2. The water used is clean tap water. The length of the chemically treated bamboo fibres are at a maximum length of 1 .5 inch. The amount of bamboo fibres added is at least 2%. The method of manufacturing bamboo fibre reinforced concrete beam is shown in FIG. 1.4. Firstly, the bamboo fibres are prepared (202). Then, cement, fine aggregates, coarse aggregates and the prepared bamboo fibres are mixed to form a concrete mixture (204). Next, the concrete mixture is casted (206) and cured (208).

The step of preparing bamboo fibres (202) is shown in FIG. 1 .5 which further comprises the steps of soaking Semantan bamboo splints in 2.5M sodium hydroxide (NaOH) for 24 hrs in ambient temperature (202a); defibrating bamboo splints to obtain bamboo fibres (202b); rinsing bamboo fibres in distilled water until the pH value of the bamboo fibres fall within the range of at least pH 6.5 to at least pH 7.5; drying the fibres at 60°C for 24 hr (202d) and storing the bamboo fibres in vacuum desiccators with silica gel to prevent moisture absorption (202e). Examples of experiments

Bamboo characteristics

The three types of bamboo species namely Betong, Beting and Semantan were tested to determine the most suitable type for use as bamboo reinforcement concrete beam (BRC) and bamboo reinforcement fiber concrete (BRFC). The bamboos are in the maturity age of 4 to 5 years and having diameter within the range of 80 to 90 mm. The mechanical properties of the bamboo were determined by conducting compression and tensile tests according to ISO 22157-1 :2004 standards.

Methodology

Stage 1 Bamboo species evaluation and selection A. Compression test

To determine the compressive strength of bamboo, compression tests were carried out on bamboo culms. The compressive strength is important to calculate the maximum allowable stresses in bamboo especially when being used as compressive reinforcement in a doubly reinforced concrete beam. Total of 3 samples per bamboo species as shown in FIG. 2.1 were used for compression test. All the bamboo samples contain central node as the real application of bamboo must include the node section as no bamboo without node for length required for construction. All bamboo samples were cut from middle portion of the bamboo as the strength is higher compared to the bottom and top section (Sakaray, Togati & Reddy, 2012). The compression was carried out by placing the measured samples in Universal Testing Machine of 100 kN with a loading range of 0.05kN/s. The load is applied in gradual increments until the sample failure. Table 1 below provides the summary of bamboo samples undergoing compression test.

Table 1 : Summary of bamboo samples for compression test.

B. Tensile test

Tensile test was carried out on bamboo splints to determine the ultimate tensile strength of the bamboo. The said tensile strength is crucial in determining the maximum allowable tensile stress in bamboo as bamboo is being used as reinforcement in concrete elements to cater tensile loads. The Tensile test was carried out by subjecting middle portion of the bamboo splints of each bamboo species with a gauge length of 300 mm and a grip portion of 150mm to universal testing machine, UTM with a loading value of 0.05kN/s. Load was continuously applied until the specimen was broken. Figure 2.2 illustrates the tensile test carried out for a bamboo sample according to the present invention. The cross section of the specimen at failure was observed. The result of load and displacement readings is shown in the Table 2 below:

Table 2: Summary of bamboo samples for tensile test

C. Thermal Gravimetric Analysis (TGA)

Thermal decomposition behaviour of bamboo and effects of chemical treatment on thermal degradation was evaluated through thermal gravimetric analysis. Thermal Gravimetric Analysis is carried out under nitrogen atmosphere with a temperature ramp of 10’C/min from 30 to 1000’C. Predetermined amount of bamboo samples was placed in alumina pan and the decomposition pattern was recorded over a period of time until the decomposition end as indicated by a plateau mass loss.

Bamboo Reinforced Concrete ( BRC )

1. Water Absorption Test.

As shown in FIG. 2.3, six (6) bamboo splints were taken from different portions of bamboo culms for the test. Bamboo splints was prepared in two types (I) untreated and (II) treated with oxide primer. All specimens were kept in an oven at 100’C for 24 hours to remove all initial moisture content in the bamboo splints. The initial moisture and thickness is recorded. All specimens were kept immersed in water at room temperature for 30 days in curing water tank. The specimens were taken out from curing tank at intervals of 15 days and 30 days for testing. During the testing, the bamboo splints are wiped off properly using dry cloth. The final saturated weight and thickness of the entire specimen were measured individually. The amount of water absorbed by the specimen is calculated as follows:

Water absorbed (g) = Final saturated weight (g) - dry weight (g)

% by weight of water absorbed= water absorbed (g)/final saturated weight (g) X 100

2. Thermal Analysis Thermal decomposition behavior of bamboo and the effects of chemical treatment on thermal degradation were studied via thermal gravimetric analysis. Thermal gravimetric analysis, TGA was carried out under nitrogen atmosphere with a temperature ramp of 10°C/min from 30 to 1000 °C. The analysis was performed using a Hitachi STA7200 thermal gravimetry analyzer. A predetermined amount of bamboo sample was placed in an alumina pan and the decomposition pattern was recorded over a period of time until the decomposition end as indicated by a plateau mass loss.

3. Compression Test

Twelve (12) bamboo samples, i.e. 3 samples for each type and condition were prepared for compression test as summarized in Table 3. All the bamboo samples contain a central node. The reason to include the node was due to the fact that the real application of the bamboo must include the node section because no bamboo without node for a length required for construction. The samples were cut from the middle portion of the bamboo culm as the strength is higher compared to the bottom and top section of a bamboo (Sakaray, Togati. & Reddy, 2012). The dimensions of the samples are measured were then placed in Universal Testing Machine of 1000 kN with a loading rate of 0.05 kN/s. The load is applied parallel to fiber of bamboo in gradual increments until failure is observed. The Universal Testing Machine automatically stops the measurement when it detects the sample failure. Compressive strength is determined from the ultimate load. Figure 2.4 illustrates the compression test of bamboo samples according to the present invention.

Table 3: Summary of bamboo samples for compression test 4. Tensile test

Similar to the compression test a total of 12 bamboo splints which comprises of 3 samples for each type and condition as summarized in Table 4 was prepared. Three bamboo splints of each species were taken from the middle portion of bamboo culm for the test, with a gauge length of 300 mm and a grip portion of 150 mm on each side of the specimen. The loading rate of the Universal Testing Machine, UTM was 0.05 kN/s. The load was continuously applied until the specimen is broken. The cross-section of the specimen at failure was observed. The load and displacement readings were recorded at regular intervals for each specimen. Figure 2.5 illustrates the tensile test of bamboo samples according to the present invention.

Table 4: Summary of bamboo samples for tensile test 5. Aging and weathering test for BRC

Age weathering tests were carried out on the samples using wooden formwork and tested to failure under three-point bending as shown in FIG. 2.6. The dimension of formwork is 20 mm X 20 MM with a length of 200 mm. The above provided dimension is the maximum size that can be placed in the age weathering chamber.

Concrete was cast for BRC and cured for 28 days before testing. The specimen was tested under ASTM G154 which tests the prolonged use under exposure of rain, condensation and sunlight. The standard accelerated age weathering tests takes 21 days after the initial curing stage.

6. Structural test Structural test is conducted to determine the structural behaviour of bamboo reinforced concrete beams. Table 5 below shows the summary of total number of beams considered in the study.

Table 5: Summary of total beam specimens for testing 7. Material Preparation a) Bamboo

The bamboo for study is collected from Raub, Pahang. The bamboo was air dried by stacking horizontally upon collection and placed in the laboratory. The collected bamboos were stored in a rack with proper stacking for natural drying. FIG. 2.7 illustrates a photograph of bamboo stacked horizontally for air-dried according to the present invention. The bamboos were split with a total weight of 1 .5 m as bamboo reinforcement in concrete beam. Figure 2.8 shows the splitting of bamboo into bamboo splints for use as reinforcement in concrete beam according to the present invention. b) Chemical Treatment

Bamboo splints were chemically treated using 1 .25 M sodium hydroxide, NaOH solution for 15 to 20 minutes to mitigate fungus growth as shown in FIG. 2.9. Bamboos were then removed from the chemical tank after 20 minutes and sun dried for at least 7 days before used for beam reinforcement. Bamboos are highly hygroscopic and will undergo degradation in the long term. Therefore, the bamboos cannot be placed in concrete in its natural state. The reinforcement specimen must be treated using black oxide primer. Oxide primer functions as a water repellent and also protects bamboo against insect infestations. Upon coating with oxide primer, the bamboos are left for drying at ambient temperature for two days until completely dries. c) Formwork and Reinforcement Preparation

The beams are in the dimension of 150 mm and 200 mm with length of 1500 mm. Two steel bars of a diameter of 10 mm were used as the bottom and top reinforcement. The steel shear links of diameter of 6 mm were placed with the spacing of 300 mm centre to centre. The reinforced beam is used as a reference beam, control beam for comparison with the bamboo reinforced concrete, BRC beam. The reinforced concrete design of steel area of reinforcement for compression and tension was calculated according to Eurocode 2. Total of six, 6 bamboo splints were used for the bamboo reinforcement.

Three, 3 bamboo splints were tied as bottom and top reinforcements. The shear links were made of bamboo splints that cut into 120 mm length, same length as steel shear link. The bamboo splints were then tied using steel wires. Two, 2 cm space is created between splints for strengthening. A screw was used to create the inter-splint gap. All the bamboo splints and links were coated with black oxide primer to provide water repellent effects to prolong the lifespan of the structure. d) Casting and curing

Before casting, concrete cube moulds and formwork were greased. The greasing of cube moulds before concrete casting is shown in Figure 2.10(a). Figure 2.10(b) shows the bamboo reinforcement beam in a greased formwork. The process of beam casting and curing are illustrated in FIG. 2.11 (a) - 2.11 (c). The beams were cast in wooden formworks using ready-mixed concrete of grade 30 MPa (without admixture). After concrete casting, the beams were covered using a polyethylene sheet for 24 hours to prevent hydration. The casting includes 12 concrete cubes for the curing age of 3, 7, 14 and 28 days as well as 15 beams to be tested at 14 and 28 days. All the beams were cured using wetted gunny bags. Slump test was conducted upon arrival of ready-mixed concrete in accordance with British Standard, BS 1881 : Part 102, 1983. e) Testing

Slump test was conducted and observed during concrete pouring in accordance to reference standards, BS 1881 Part 102, 1983 as shown in Figure 2.12. Compression test is carried out to determine the compressive strength of the hardened concrete specimen, cubes according to BS 1881 : Part 116: 1983 as shown in Figure 2.13.

Four-point bending test was conducted using Universal Testing Machine, UTM of 500 kN in the concrete laboratory of Faculty of Civil Engineering & Earth Resources, Universiti Malaysia Pahang. The loading points were placed 200 mm apart and the load is transferred to the beam by using a spreader beam. The test was conducted according to the standard BS EN 12390-5:2000 as shown in Figure 2.14. The beam is tested under failure using four point bending test after a curing period of 14 and 28 days. Linear variable displacement transducer (LVDT) was placed at the bottom soffit of the beam to measure the beam deflection. The failure mode and crack pattern of the beam was recorded upon the beam failure.

Bamboo Fiber Reinforced Concrete, BFRC a) Extraction of Bamboo Fiber A combination of chemical and mechanical techniques was adopted to obtain the fibres from the raw bamboo in order to avoid the degradation caused by hydroxyl groups of natural fibre. Sodium hydroxide pellets were purchased from Permula Chemicals Sdn Bhd, Kuantan, Pahang. The bamboo strip is soaked in an aqueous 2.5 M NaOH solution for 24 hours at ambient temperature. Subsequently, the bamboo strips were removed and mechanically defibrated using a mill roller machine to obtain the bamboo fibre as shown in FIG. 2.13. The spliced bamboo strips were rolled flattened repetitively until the fibres are produced. Subsequently, the extracted bamboo fibres then rinse with distilled water repeatedly until the pH of the fibre fall in the neutral range, pH 6.5 to 7.5, normally tested using a Universal Indicator Paper. Once the Universal Indicator Paper exhibits a pH value around 7, the bamboo fibres undergo a drying process in an electric oven at 60ºC for 24 hours. The tensile strength of heat treated bamboo fibres increases as compared to the untreated bamboo fibres (Cao, Sakamoto, & Goda, 2007). Lastly, the dried bamboo fibres are kept in vacuum desiccators with silica gel to prevent moisture absorption. b) Cutting of Bamboo Fiber

The dried bamboo fibre is cut into a desire length for the trail mixes using scissors. c) Material Preparation

Ordinary Portland Cement, fine aggregates and coarse aggregates are used in concrete mix. The concrete grade adopted is 30 MPa. The concrete is mixed with the bamboo fibre to produce a bamboo fibre reinforced concrete, BFRC. a) Ordinary Portland Cement, OPC

Ordinary Portland cement manufactured by YTL Orang Kuat which is packed in 50 kg paper bag and suitable for structural concrete is used. This type of cement is produced with quality assurance and is certified to MS EN 197-01 :2004, MS ISO 9001 , MS ISO 14001 , OHSAS 18001 and MS ISO 50001. The type of cement used is a non-composite without the additional by-products such as fly ash. b) Fine Aggregates

The size of fine aggregates used in this study is less than 4.75 mm. The source of fine aggregates used is locally available river sands passing through a 4.75 mm sieve. The river sand was left air dried prior to passing through a sieve. The geometry of river sand can be either crushed or rounded and both types can be used in concrete mix. c) Coarse Aggregates

Coarse aggregates are essential ingredient in the concrete mix. The said coarse aggregates are crush granite with size greater than 4.75 mm. Coarse aggregates in the size of 10 mm and 20 mm are used in concrete mixing to provide an interlocking mechanism among the angular aggregates while round aggregate possesses lower internal friction promote the flow of the concrete mix. Suitably, a ratio of 1 :2 for a combination of 10 mm and 20 mm coarse aggregate were used. d) Water Content

Water source used originates from tap water. The water used should be clear and free from any impurities. During concrete mixing process, water is added gradually into mixer to ensure quality of mixing. The water to cement ratio, w/c for this project is 0.50. e) Beam Specimens

A total of twelve (12) rectangular beams and twelve (12) cubes were cast in one mix. Steel mould was used and its specifications were compiled according to standard of codes. Beam steel moulds of size 100 mm x 100 mm x 500 mm as well as 100 mm x 100 mm x 750 mm were used to cast concrete beams while 100 mm x 100 mm x 100 mm size of cube moulds were used to cast on concrete cubes. The releasing agent, mould oil or grease was applied to the inner surface of the formwork to ease removal of the formwork and to reduce the adhesion of concrete with formwork or mould surface. f) Concrete Mix Design

The bamboo fiber reinforced concrete, BFRC study is divided into three phases. In the first phase, the effect of different fibre length ranging from 1 inch, 1.5 inch, 2 inch and 2.5 inch on the BFRC is studied up to 28 days of curing.

The fibre length that yields the strongest BFRC based on 7 days curing is then chosen to study the effect of fibre loading ranging from 0% to 2%. In the third phase, based on the results obtained, selected fibre length and fibre percentage were used for the structural properties study. Concrete characteristic strength of 30 N/mm ² at 28 days is designed and adopted for all the three phases of concrete mixing. The mix proportion of 1 :1.85:3.02 and free water to cement ratio of 0.50 are chosen. Table 6 summarizes the number of specimens in phase 1 .Table 7 summarizes the design mix proportions for both phase 1 and 2. Table 6: Number of specimens in phase 1

Table 7: Design mix proportions in phase 1 and 2

In the second phase, concrete is mixed with fibre percentages of 0 % to 2 %, were cast into concrete cubes of dimension 100 mm x 100 mm x 100 mm as well as the beam of size 100 mm x 100 mm with a length of 500 mm.

In each round of concrete casting, a concrete mixer was used to sufficiently cater for a total of 12 cubes and 12 beams specimens with same concrete used for all samples to ensure data consistency. Table 7 summarizes the total number of specimens in phase

2. Table 7: Number of specimens in phase 2 In phase three, a total of 6 beams were considered for the structural properties test, in which 3 control beams with steel reinforcement were included. Two diameter 10 mm bars as top and bottom reinforcement in a beam dimension of 100 mm x 100 mm and a length of 750 mm was used. The remaining 3 beams were pure bamboo fibre reinforced concrete, BFRC beam without steel reinforcement. Each concrete casting includes 6 beams to be tested on 14 and 28 days, as well as a total 12 cubes for 3,7, 14, and 28 days of curing.

Concrete mixing, casting and curing

The weighted dry ingredients are mixed dry in a concrete mixer for two, 2 minutes to ensure homogeneity and the bamboo fibres were then spread into the concrete mixer during mixing. After 2 more minutes, water was added and mixed thoroughly for 3 minutes. Slump test was conducted immediately after the fresh concrete was mixed homogeneously. All the cubes and beams were cast simultaneously and concrete vibration was performed using vibrating table for 10-15 seconds once the mould is fully filled. A total of three, 3 layers of concrete were filled into the mould, where each layer was compacted with 25 blows of tamping rod.

Twelve (12) concrete cubes and twelve (12) concrete beams were demoulded after 24 hours of casting. The cubes and beams were placed in water for water curing of 3, 7, 14 and 28 days. a) Aging and weathering test on Bamboo Fiber Reinforced Concrete, BFRC Sample for the age weathering test were prepared using a wooden formwork of 10 mm x 20 mm with a length of 200 mm and tested to failure under three-point bending. FIG. 2.14 illustrates the testing of weathered bamboo fibre reinforced concrete, BFRC specimens.

All specimens were prepared using a 1 .5 inch dried bamboo fibre mixed with concrete grade 30 MPa. Concrete was cast for BFRC mixes and cured for 28 days before testing. The specimen was tested under ASTM G154 which tests the prolonged use under exposure of rain, condensation and sunlight. The standard accelerated age weathering test takes 21 days after the initial curing stage. b) Testing Slump test was conducted immediately on the fresh concrete and hardened properties test includes compression, flexural and structural properties tests are presented in the following sections.

Slump test

Slump test was conducted and observed during concrete pouring in accordance to reference standards, BS 1881 : Part 102, 1983. The workability and consistency of the fresh concrete were determined and measured in this laboratory testing. Slump cone, based plate, tamping road and measuring tape was used during the test.

Compression test Compression test is carried out to determine the compressive strength of the hardened concrete specimen, cubes referring to BS 1881 : Part 116: 1983. The test was conducted at different ages of concrete at 3, 7, 14 and 28 days. FIG. 2.15 illustrates the compression strength test of the bamboo fibre reinforced concrete specimens, cubes.

Flexural test

Flexural test is carried out to determine the flexural strength of concrete specimens, beam accordance to the ASTM C 78-02. The flexural strength test of bamboo fibre reinforced concrete beam was conducted using flexural four-point loading machine as illustrated in FIG. 2.16. Structural properties test

The beams for structural test were cast with the dimension of 100 mm x1 00 mm x 750 mm. The test was conducted using four-point loading machine as illustrated in FIG. 2.17.

RESULTS AND DISCUSSION

STAGE 1: BAMBOO SPECIES EVALUATION AND SELECTION a) Compression Test

Results in terms of stress-strain curve and failure pattern are presented in the following sections. Table 8 summarizes the results of three types of bamboo with the ultimate compressive force and compressive strength. From the results obtained, the species with the highest compressive strength or better known as compressive stress are identified as Betong, Semantan and Beting, with an average ultimate compressive strength of 41.4, 35.33 and 21 .91 MPa, respectively. Table 8: Summary of compressive force and strength of bamboo samples a) Stress-strain curve

The comparison of stress-strain curves between three bamboo samples from the same species, namely Betong, Semantan and Beting, respectively were shown in FIG. 3.1 , 3.2 and 3.3. From the stress-strain curve, it was found that the curve line of bamboo Semantan exhibited steeper slope at the early phase of compression as illustrated in Figure 3.2. This indicates that bamboo Semantan has higher modulus of elasticity compared to Betong and Beting. All the stress-strain curves of the Semantan species have achieved the ultimate compressive stress within a strain of 0.015. Flence, it is noteworthy to mention that bamboo Semantan possess better compressive strength characteristics compared to Betong and Beting. b) Failure pattern

The failure pattern of Betong, Semantan and Beting bamboos are shown in FIG.3.4 (a), (b) and (c). From the results obtained, it was found that the common failure of bamboo in compression is in two modes (i) cracking and (ii) crushing of fibers. Cracking of fiber were identified at the compression face at the top of loading Visible vertical crack line was seen only at the top surface of the bamboo. The crack did not penetrate until the internodes due to widely spacing of fiber, stiff behavior at node points, additional cross-sectional area at nodes as walls are thicker on both sides of the node as well as dense mass present at nodes.

The cracking pattern of bamboo Semantan is illustrated in FIG. 3.4(a) It was seen that the cracking of fiber was at the top and bottom face of the compression loading. Similar as to that of Betonq, no propagation of cracks was found at the central nodes.

Unlike Betong and Semantan, Beting species exhibited mix mode of failure which include cracking and crushing of fibers, as shown in FIG. 3.4 (b)

On the other hand, FIG.3.4 (c) shows the cracking pattern of three bamboo species at the bamboo culm, (a) Betonq, (b) Semantan and (c) Beting. FIG.3.4 (c) shows a more severe crack was observed for Betong bamboo compared to Semantan and Beting. This may be due to the smaller diameter in Betong bamboo compared to the other two species. c) Tensile Test

Tensile test results are presented in terms of stress-strain curve and failure pattern in the following section. Table 9 summarizes the ultimate force and tensile strength for three different types of bamboo species. From the table, it was found that the ultimate tensile strength of bamboo splints is 170.32 MPa, species of Semantan. On the other hand, the lowest ultimate tensile strength was 123.6 MPa for the species of Betong.

Table 9 Summary of tensile strength of bamboo samples d) Stress-strain curve FIGS. 3.5 to 3.7 show the stress-strain curve of bamboo splint for three different bamboo species. From the stress-strain curves, it was found that bamboo Betong and Semantan having similar tensile strength characteristics as the trend line is almost similar. The curve line of both Betong and Semantan exhibited low early tensile stress at the early stage of loading, and eventually showed almost proportional increment between stress and strain. The ultimate tensile stress was achieved within the strain of 0.06 to 0.08 in both Semantan and Beting, while Betong achieved the ultimate tensile stress within the strain of 0.08 to 0.1 . This indicates that Betong has higher capability to resist tensile stress, time dependent and possess high ductile behaviour before failure compared to Semantan and Beting; which is suitable to be used as tension reinforcement in concrete beam. e) Failure pattern All the bamboo specimens have shown brittle failure at the nodes in all types of bamboo species which indicates that node failure is the most critical section for failure under tensile stresses (Gupta, Ganguly, & Mehra. 2015). Besides failure at the nodes, splitting of fibers as well as combined node and splitting type of failure were identified. FIG. 3.8(a) to 3.8(c) show the failure pattern of Betong, Semantan and Beting bamboo. Unfortunately, the bamboo node is unavoidable in construction because bamboo has a node after around 25 to 40 cm.

The failure pattern of Betong is very brittle due to the breaking of fibers into two segments at the node as shown in FIG. 3.8(a). On the other hand failure in combined node and splitting of fiber was seen in both Semantan and Beting as shown in FIG. 3.8(b) and 3.8(c). f) Comparison of Bamboo

Three species of bamboo were compared in terms of compressive and tensile strength by taking the average value from the specimens from each species. The thermal decomposition of the bamboo is also compared. g) Compressive Strength

The stress-strain curve in FIG. 3.9 shows that the trend line of Betong and Semantan bamboo was in good agreement showing an elastic-plastic phase upon reaching the ultimate compressive strength. In contrast, Beting bamboo exhibited a lower compressive strength, about 30% lower in strength compared to both Betong and Semantan bamboo. This indicates that both Betong and Semantan bamboo is suitable to be used as compression reinforcement in concrete beam. h) Tensile Strength FIG. 3.10 shows the comparison of stress-strain curve between Betong, Semantan and Beting in which the average values of stress and strain from the most similar trend line of minimum 2 and maximum 3 samples from the respective bamboo species were chosen. From the graph, Betong bamboo possesses the highest average ultimate tensile stress, 147.4 MPa as well as showed higher ductility as compared to Semantan 137.2 MPa and Beting 135.5 MPa. This signifies that the most outstanding type of bamboo species suitable to be used as tension reinforcement is Betong, followed by Semantan and Beting. i) Thermal Gravimetric Analysis, TGA

FIG. 3.11 shows the thermal decomposition pattern of Betong, Semantan and Beting bamboo. Initial weight loss was observed in the temperature range of 25 to 220°C is attributed to the entrapped moisture evaporation from the bamboo sample (Oyedun et al., 2013). The second and major weight loss was observed in the temperature range of 220°C to 375°C due to the simultaneous decomposition of hemicellulose and cellulose, during this temperature range lignin also partially decomposes (Lopez-Velazquez et al., 2013). The weight loss at a temperature range from 375°C to 800°C is due to the decomposition of the lignin (Jiang et al., 2012). It can be observed from the TGA results that Beting has the lowest decomposition temperature at 537°C, whereas Semantan shows the highest thermal stability with a decomposition temperature of 997°C. Despite its strength, Betong only has a moderate thermal decomposition temperature at 650°C. The yields obtained from the pyrolysis of raw bamboo are as follows: Beting (15.39%), Betong (7.75%) and Semantan (4.40%). j) Comparison of Bamboo with Steel

FIG. 3.12 shows the comparison of all three bamboo species; Betong, Semantan and Beting with steel bar of diameter 10 mm. From the result, it can be clearly seen that the steel bar possesses an elastic-perfectly plastic behavior. The strain of steel increased with minimal increases in stress due to strain hardening. The steel bar yielded at 500 MPa and achieved an ultimate tensile stress at 549 MPa before experiencing gradual failure. All the bamboo species; Betong, Semantan and Beting only managed to achieve about 26.8%, 25% and 24.6% of the ultimate tensile stress of the steel, respectively. Despite the low tensile stress of bamboo; Betong bamboo exhibited ductile behaviour with gradual increase of stress and strain similar as steel.

STAGE 2: BAMBOO REINFORCED CONCRETE

Physical Properties Test

Testing for the physical properties include water absorption test, compression and tensile tests were performed before commencing work on BRC beams and BFRC. The physical properties tests are discussed in the following sections. a) Water Absorption Test

Bamboo changes in its dimension when it loses or gains moisture in a similar manner to wood and timber. Due to its hygroscopic characteristic, bamboo tends to absorb moisture from the air and surroundings. Bamboo splints can absorb more than 50% of water by weight whereby it absorbs and reduces a part of water added into the concrete mix for hydration process. Bamboo splint swells in wet concrete as it absorbs moisture. The concrete eventually dried and the bamboo splints contracts, thus creating spaces between the bamboo-cement contacts. This caused a reduction in the strength of the bamboo- concrete bond which may cause structural failure. Therefore, it is important to do oxide primer coating on the bamboo before used for reinforcement.

FIG. 4.1 shows the graph of the amount of water absorbed versus number of soaking days. The graph shows that water is absorbed by the bamboo specimen at a faster rate for the initial 15 days. The trend of absorption becomes slower as it reaches equilibrium towards 30 days of soaking. The percent increase in thickness after 30 days of soaking exhibited as high as in the range of 30% to 90% in non-treated samples whereas 50%- 80% in treated bamboo samples. The result shows that the probability of water absorption and swelling of the bamboo splints is high once the bamboo is exposed to wet surroundings. This eventually generates additional stresses in reinforced concrete elements when applied as reinforcing material. Hence, it is important to coat the bamboo with oxide primer as it can act as waterproofing compound.

FIG. 4.2 shows the relationship between amounts of water absorbed versus number of nodes which can be approximated as a linear. The water absorption capacity of bamboo increases with the increase in the number of nodes, which is due to the powder like grains at the nodes causing more water absorption. From the results obtained, it was found that the water absorption capacity of bamboo was slightly reduced with oxide primer. However, there is still significant absorption of water in treated samples. This indicates that oxide primer did not provide a satisfactory coating of the bamboo due to its high viscosity and stripping properties in the presence of water. Moreover, it was observed that oxide primer is not effectively coating the entire bamboo surface, possibly due to lack of affinity between the bamboo and the liquid oxide primer. b) Thermal analysis result FIG. 4.3 shows the thermal decomposition pattern of the treated bamboo. The initial weight loss observed in the temperature range of 25°C to 220°C is due to loss of entrapped moisture by evaporation from the bamboo sample. The weight loss observed in the temperature range of 220°C to 375 °C is due to the simultaneous decomposition of hemicellulose and cellulose, as well as a partial decomposition of lignin. The weight loss at a temperature range from 375°C to 800°C is due to the decomposition of lignin. It can be observed from the result that the NaOH treated bamboo fully decompose above 920°C, meanwhile the NaOH + oxide primer treated bamboo only decompose fully above 1000°C. The result shows that further treatment with oxide primer enhanced the thermal stability of the bamboo. c) Compression Test

FIG. 4.4 shows the stress-strain curve of compression test for untreated raw and dried samples as well as the bamboo treated with NaOH and Oxide Primer. From the result obtained, the untreated dried sample exhibited the highest stress, 61 MPa. A similar curve trend was observed for untreated raw sample and treated NaOH. This type of samples achieved a maximum stress with a minimum increment in strain up to failure. In contrast, the bamboo sample treated with oxide primer showed higher in ductility, in which the strain was increased gradually with the increase of stress up to failure. The stress value achieved by treated oxide primer was about 44 MPa. The result shown in FIG. 4.4 should be treated with caution. We opined that the variation of stress for untreated dried, NaOH treated and NaOH + oxide primer treated is mainly due to the variation of the bamboo, not the treatment.

However, we can generalise that all bamboo specimens have a stress in excess of 38 MPa. d) Tensile Test

The stress - strain curve of tensile test for untreated raw and dried samples as well as treated with NaOH and Oxide Primer is shown in FIG. 4.5. Untreated dried sample exhibited the highest tensile stress, about 153 MPa. The trend line shows stress proportional to the strain and failed after reaching the maximum stress. On the other hand, treated oxide primer and treated NaOH exhibited a lower tensile stress with the increase of strain which indicates ductile behaviour. The maximum tensile stress of treated oxide primer achieved as 126 MPa whereas treated NaOH was 92 MPa. On the other hand, the untreated raw bamboo sample showed the lowest tensile stress, approximately 40 MPa before failure.

Bamboo Reinforced Concrete ( BRC ) Beam

The results of compression test of the casted cubes and the beams structural behavior are presented and discussed in the following sections. a) Compressive strength From the compressive strength results, it was found that the 28 days curing of 30 MPa ready-mixed concrete achieved the targeted strength as summarized in Table 9. FIG. 4.6 Illustrates the compressive strength of the ready-mixed concrete at 3,7,14 and 28 days. The compressive strength achieved nearly 35 MPa, which is above the design specification of 30 MPa.

Table 9: Summary of total beam specimens for testing Structural properties test at 14 days

The results of the beam structural behavior are presented in terms of load-deflection behavior and crack pattern in the following sections. b) Load-Deflection Behavior FIG. 4.7 shows the load-deflection of the control beams (steel reinforced) tested at 14 days of curing. As shown in FIG. 4.7, the results of the three beams were almost similar exhibiting higher ductility after reaching the plastic phase. From the results obtained, control beam 1 , 2 and 3 achieved an ultimate load of 52 kN, 55 kN, 53 kN, respectively. Control beam 2 showed a brittle failure after the maximum load was attained. FIG. 4.8 shows the load-deflection curve of the BRC beam with NaOH + oxide primer for specimen 1 , 2 and 3. As shown in FIG. 4.8, the bamboo reinforced beams exhibited first cracking at 10 kN and second cracking at 12 kN. It was found that the deflection increases proportionally to the applied load until beam failure is reached. BRC beam with NaOH + oxide primer 1 achieved an ultimate load of 40 kN before beam failure. A similar ioad- deflection curve trend was observed for beam 2 and 3. The maximum load achieved by both BRC beams with NaOH + oxide primer 2 and 3 was 49 kN and 50 kN, respectively.

FIG. 4.9 shows the load-deflection curve for comparison purposes between BRC with

NaOH + oxide primer and control beams. As shown in FIG. 4.8, it shows that BRC beams exhibited first cracking and second cracking at early stage compared to the control beams. After cracking, the load-deflection curve of the BRC beam was seen entering a plastic phase compared to control beams was still in the elastic phase. Although BRC beams with NaOH + oxide primer reached the plastic phase earlier, however, it achieves the maximum load comparable to that of the control beam due to strain hardening in the treated bamboo reinforcement. Hence, from the results obtained, the beam capacity achieved with 6 bamboo splints as reinforcement in concrete beam is comparable to the beam capacity of control beams with 4H10 steel reinforcement (A _s = 452 mm ² ). c) Crack Pattern

Crack pattern of the control beam is shown in FIG.4.10. From the results obtained, all the beams failed in bending except CB-2 which experienced mixed mode of failure in bending and shear. Vertical cracks were formed at the middle third span of the beam at early strength and eventually the number of vertical cracks increases and propagates towards the loading points. This indicates that the tension reinforcement is able to resist the tensile stresses in the beam that eventually leads to cracking.

In contrast, the crack pattern of BRC beams with oxide primer is shown in FIG. 4.11 It was observed that the number of vertical cracks was found lesser compared to the cracks in the control beams. Few vertical cracks were seen formed at the middle third of the tension zone and eventually penetrated towards the neutral axis of the beam. This shows that bamboo reinforcement as tension reinforcement did not effectively resist the tensile stresses as that similar to the steel reinforcement. The crack width of the vertical cracks in BRC beams were found more visible compared to the crack width in the control beams. The failure mode of all BRC beams was in bending. Structural properties test at 28 days a) Load-deflection behaviour

FIG. 4.12 shows the comparison of load-deflection curves of the control beams after 28 days of curing. It was observed that the three beams exhibited similar behaviour at the early stage of loading, with a linear line in the elastic phase. The curve trend of the control beams changes as the stiffness of the beam was reduced after the first cracking. The load increase gradually with deflection until the ultimate load was achieved. A gradual failure was observed in control beams 1 and 2 due to the plastic deformation which indicates ductile behaviour. Meanwhile, control beam 3 showed brittle failure as a sharp decrease in load was observed after the ultimate load was reached. Control beams 1 , 2 and 3 achieved an ultimate load of 47 klM, 51 kN and 50 klM, respectively. Not much difference between the beam load at 14 and 28 days as expected due to minimal improvement of concrete prior to 14 days of curing.

FIG. 4.13 shows the load deflection behaviour comparison of BRC beams with bamboo treated with NaOH without oxide primer. A linear straight line proportional to load and deflection was identified for the three beams NaOH-1 , NaOH-2 and NaOH-3. However, after the first crack, a transition from the elastic phase to the plastic phase was observed. The load-deflection curve trend is consistent for the three beams, whereby all the beams failed abruptly after the highest load was achieved. Apart from that, BRC beam NaOH-1 exhibited higher ductility compared to BRC beams NaOH-2 and NaOH-3. The highest ultimate load achieved by BRC beams treated NaOH 1 , 2 and 3 was 49 kN, 44 kN and 40 kN, respectively. The result at 28 days is same as those obtained after 14 days of curing.

FIG. 4.14 shows the load deflection behaviour comparison of three BFC beams with bamboo treated with NaOH and coated with oxide primer respectively. It can be observed that the first crack was identified at about 10 kN before changing from elastic to plastic region. The BRC beams with oxide primer showed consistency with similar beam stiffness. The load continues to increase linearly with deflection until the initiation of cracks causing reduction in the beam stiffness. The beams failed immediately after the ultimate load was attained. BRC beams coated with oxide primer-1 , 2 and 3 achieved a maximum load of 55 kN, 46 kN and 59 kN, respectively. For the case of BRC, NaOH + Oxide Primer, beam performance at 28 days is better than that of 14 days of curing.

From the results obtained, load-deflection curve of control beam, BRC beam treated NaoH and treated NaOH + oxide primer was compared as shown in FIG. 4.15. The comparison was made on the beams with the highest ultimate load achieved. From the figure, BRC beam with NaOH + oxide primer achieved the highest ultimate load, 59 kN, 14% higher than the ultimate load of control beam CB-2 and 25% higher than the ultimate load of bean with treated NaOH-2. From the curve trend, BRC beams in both NaOH and NaOH+ oxide primer exhibited a linear line in the strain hardening phase unlike steel reinforced beam with a nonlinear line in phase of strain hardening. The behaviour of BRC beams with both NaOH and NaOH + oxide primer was rather brittle in nature compared to the ductile control beam that failed in a gradual manner. Although BRC beams possess brittle behaviour whereby the beam stiffness is lower compared to the steel reinforced beam, BRC beams with NaOH + oxide primer showed higher plastic deformation with an increase in load and deflection proportionally up to beam failure. b) Crack pattern

FIG. 4.16 shows crack pattern of control beam, steel reinforced, CB-1 , CB-2 and CB-3. It was observed that many vertical cracks were formed along the tension zone in the mid -span of the beams. With the continuation of load, the vertical cracks eventually spread towards the support and propagated upwards to the loading point. The crack width was seen enlarged before beam failure. The failure mode of CB-1 and CB-2 was in bending whereas beam CB-3 failed in a mixed mode of bending and shear failure. in contrary to the crack pattern of control beams, only few vertical cracks were traced in the mid-span along the tension zone for BRC beams treated with NaOH as shown in FIG. 4.17. With the application of load, these vertical cracks propagated vertically up to the neutral axis of the beam towards the loading point. Cracks formed near to the support propagated diagonally towards the loading point. Diagonal crack widths were seen widened before beam failure. The beams failed in shear with a diagonal crack near to the support.

Compared with the crack patterns of BRC beams with NaOH, only few main vertical cracks were traced in the mid-span along the tension zone for BRC beams treated with NaOH + oxide primer as shown in Figure 4.18. These main vertical cracks propagated vertically up to the neutral axis until the loading point. Very few extended cracks were formed from the main vertical cracks in BRC beams treated NaOH + OP. The failure modes of the BRC beams with NaOH + OP were in bending. c) Age weathering

Weathered Control BRC, Without Oxide Primer, OP

The age weathering test conducted according to ASTM G154 was performed to study the prolonged use of BRC under exposure of rain, condensation and sunlight. Control beam in this study is a beam strengthened by bamboo treated only with NaOH. The control beam is compared with the beam strengthened by oxide primer coated bamboo that undergoes prior treatment with NaOH. FIG. 4.19 shows the graph of load versus deflection of weathered BRC using bamboo treated either with NaOH only, control or NaOH + OP for BRC + OP specimens.

As shown in FIG. 4.19, the maximum load attained for control specimen was in the range of 1700 N - 2000 N. It was observed from the trend of curve, that first crack was observed at the very initial stage of loading, within 0.5 mm. A sharp decrease in load was noticed before the load increase again due to strain hardening effects by the bamboo in concrete. In the plastic phase, slight decrease and increase in load was observed due to yielding of the bamboo reinforcement. A gradual failure was observed was the load decrease with the increase in deflection. The curve trend shows that the BRC+ OP specimens managed to reach an ultimate load in a range of 1300 N to 2300 N. It was found that the curve trend of weathered BRC + OP2 was similar to the weathered control BRC in which initiation of first crack started at the beginning of the loading stage followed by strain hardening of bamboo. In contrast, bamboo coated with OP in weathered BRC+OP1 showed an unsmooth nonlinear curve. This occurred as the bamboo experienced cracking internally at the same time exhibiting strain hardening effects. Effects of strain hardening continued to takes place up to the plastic phase of the specimen. Gradual failure was observed with consistent load increased in deflection up to beam failure.

Comparison of weathered specimens

Comparison of the weathered specimens of the control BRC and BRC with OP in terms of load versus deflection is shown in FIG. 4.20.The result shows the specimens non-coated and coated with oxide primer is almost similar. Both coated BRC +OP specimens showed steeper slope indicating a higher stiffness compared to control BRC specimens. In addition, weathered BRC+OP1 also has a good ductility compared to the control BRC specimens. The result suggests that weathering test according to ASTM G514 in this work if anything does not cause water absorption to the bamboo strengthening sticks. This is due to absent of cracks in the concrete specimen; hence water from simulated rain and condensation if anything only contributes towards curing the concrete. Thus, the BRC subjected to weathering is actually stronger than that not subjected to weathering test. However, in real life application, care should be taken to ensure that BRC has no defect i.e. cracks to ensure longevity of the structure. Weathered vs Unweathered specimens

Comparison of the weathered and unweathered specimens of control BRC is shown in FIG. 4.21 . From the load-deflection curve, it was found that unweathered specimens exhibited high ductility, in which the deflection was up to 14 mm. Weathered specimens showed higher load as the specimens already gone through the aging process with concrete strength increase with time and the strength of the specimens is expected to be higher than the unweathered at the same time poor in ductility. Meanwhile, specimens without the aging process exhibited lower in load but possess higher ductility. Aging process does not affect the ultimate strength of the BRC, indicating that water from simulated rain and condensation is not absorbed into the concrete beam. If anything, the strengthening bamboo sticks is not exposed to water which may cause it deterioration. As discussed earlier, the specimen in this case is free from any structural defect i.e. no cracks, hence water absorption does not occur.

FIG. 4.22 shows the comparison of load-deflection curve for weathered and unweathered BRC+OP specimens. It was observed that both the unweathered specimens exhibited a marginally lower stiffness but possess good ductility characteristics compared to the weathered specimens. The curve trend of weathered BRC+OP specimens shows a rather brittle characteristic. Compared to the control BRC, addition of OP does not provide extra ductility of the specimen, although OP treatment increases the strength of the specimen slightly.

Crack pattern

FIG. 4.23 shows the crack pattern or weathered BRC1 and BRC2 specimens. FIG. 4.23 (a) shows vertical cracks were initiated in the middle third of specimen, followed by diagonal cracks formed towards the support leading to the specimen failure. FIG. 4.23 (b) shows diagonal cracks formed near to the support, which widened further upon failure of the specimen. The specimens showed failure due to bending in bamboo reinforcement and concrete spalling.

Similar crack pattern was observed in weathered BRC specimens coated with oxide primer. The failure in bending with vertical cracks first initiated in the mid-span of the specimens. This crack eventually enlarged with the forming of diagonal cracks in FIG. 4.24. The specimen showed spalling of concrete exposing the bamboo reinforcement upon failure.

In contrast, the crack pattern of specimens under unweathered conditions of control BRC were found not as severe as those specimens under weathered conditions. Only vertical cracks were formed in the mid-span of the specimens as shown in FIG. 4.25(a) and Figure FIG. 4.25 (b). Upon failure of specimen, widened crack width of the vertical cracks was observed as the cracks propagated up to the loading point. Unlike the crack pattern observed in weathered BRC+OP1 and BRC+OP2 specimens, the crack pattern observed in unweathered BRC specimens were found not critical as shown in as shown in FIG. 4.26 (a) and (b). It was found that the vertical cracks were formed in the mid-span of specimen as well as hairline diagonal cracks near to the support. These hairline cracks eventually penetrated diagonally to the loading point with slightly widened in crack width upon failure of specimen as shown in Figure 4.26(a). No spalling of concrete was traced in these specimens. From the crack pattern, it was apparent that the BRC is getting stronger as they aged, thus suggesting a good prolonged used of BRC.

STAGE 3: BAMBOO FIBRE REINFORCED CONCRETE BEAM a) Slump test

Slump Test was carried out for each concrete specimen mixes to determine the concrete workability according to the concrete design mix. Comparison between plain concrete and fibre concrete mixes are being discussed and the slump value with the corresponding fibre length is tabulated in Table 10. Figure 5.1 (a) shows the slump test of (a) control mix and (b) BFRC mix. Figure 5.2 shows the comparison of slump values for each mixes.

The slump value of concrete mix decreases with the increase of fibre length added into the mix. The slump value is the measurement of concrete workability. Slump value was seen decreased from 45 mm to 11 mm for the control mix and BFRC mix with 1 .5-inch fiber length and to 0 mm for the other longer fibre length specimens. The reason of decreasing workability can be explained by the greater the length of fibre, the greater the difficulty to the aggregate particle movement, restricting the mobility of the mixture and this eventually lead to the loss of workability causing the compaction process to be more difficult. Table 10: Slump value for each concrete mix _ _

Compressive strength at 14 days

FIG. 5.3 shows the comparison of control mix (plain concrete) with respect to 1 inch to 2.5 inches of 1% bamboo fibre in concrete at curing age of 14 days. Based on the results obtained, it was found that the control mix showed a higher early strength achievement in 3 and 7 days compared to other fibres in concrete. Bamboo fibres of different length in concrete exhibited a lower strength achievement whereby 1.5-inch length showed significant higher in strength compared to other fibre lengths in both 3 and 7 days of curing age.

FIG. 5.4 shows the compressive strength result of various percentages of fibre in concrete, 1%, 1.25%, 1.5% and 2% with the selected fibre length of 1.5 inches. Based on the graph, 2% fibre percentage gives an outstanding result in terms of compressive strength. 2% fibre percentage in concrete exhibited higher early compressive strength at 3, 7 and 14 days curing compared to other percentages of fibre.

Compressive strength at 28 days

BFRC cubes with 1% 1 -inch fiber length were found to have a highest compressive strength of 51 .52 MPa at 28 days. Meanwhile, the control BFRC without any bamboo fibers yielded a compressive strength of 41 .42 MPa. Other compressive strength of BRFC fiber length which include 1.5-inch to 2.5-inch showed a range of 36 - 40 MPa is shown in FIG. 5.5.

Based on the results at 14 days, 1 .5 inch fiber length was selected to determine the optimum percentages of fiber in the next BFRC casting. The compressive strength with 1.5 inch fiber length at 1%, 1.25%, 1.5% and 2% is plotted in FIG. 5.6. It was found that 2% of 1.5 inch length of BFRC demonstrated the highest compressive strength, 40.4 MPa. BFRC with 1.25% and 1.5% managed to achieve a compressive strength of 39 MPa, while the compressive strength of control BFRC only showed 37 MPa.

Failure mode

Under the leading of uniaxial compression, extensive cracks were formed in the concrete during pre-peak stage and then failed suddenly at the peak load. FIG. 5.7 shows the failure mechanism of normal plain concrete and indicates concrete to be more brittle, fails violently and suddenly. It was observed that when fibres in discrete form are introduced in the concrete, the bonding of fibres into the concrete restrained the propagation of crack, making the concrete to become more ductile instead of the usual brittle behavior. Therefore, this signifies that bamboo fibre reinforced concrete improves the post cracking load and energy absorption capacity. Flexural strength at 14 days

FIG. 5.8 shows the comparison in terms of flexural strength of control mix with respect to 1 inch up to 2.5 inches of 1% bamboo fibre in concrete at curing age of 14 days. Based on FIG. 5.8, it was found that all the fibre percentages in concrete beam exhibited similar results at the age of 3 and 7 days. Drastic changes in flexural strength only can be observed at the curing age of 14 days in which 2.5-inch length of fibre demonstrated higher in flexural strength compared to the control beam.

In terms of fibre percentages, 2% fibre percentages of 1.5-inch length showed the highest flexural strength result compared to other percentages of bamboo fibre in concrete as shown in FIG. 5.9, and hence was used for structural study as well as the 28 days study. Flexural strength at 28 days

FIG. 5.10 shows the graph of flexural strength versus curing age of 1% fiber with various lengths. Based on FIG. 5.10, it is observed that 2.5-inch achieved the highest flexural strength of 7.6 MPa, whereas the 1 -inch and 1.5-inch fiber yielded the flexural strength ranging from 7.4 MPa - 7.5 MPa. The 2-inch fiber yielded the lowest flexural strength of BFRC beam at 6.7 MPa. The result suggests that addition of fibers into concrete beam did not show significant improvement in its flexural strength. For instance, only 1% flexural strength improvement by addition of 2.5-inch fiber compared to the control beam. It was found that 2% fiber in BFRC exhibited the highest flexural strength at 8.3 MPa as shown in FIG. 5.11. This test was performed using a 1.5-inch fiber. The BFRC with 1%, 1.25% and 1.5% fiber showed almost similar flexural strength result, i.e. 7.5 MPa, 7.9 MPa and 7.6 MPa, respectively. The 1% BFRC showed the lowest early flexural strength development compared to other fiber percentages. This signifies that the higher the percentages of fiber, the higher the flexural strength achieved.

Failure mode

FIG. 5.12 depicts the failure mechanism of plain concrete beam. During testing, all the plain concrete beams experienced sudden failure with large crack. FIG. 5.13 shows a reduction in sudden failure and crack size for BFRC as the fiber provides resistance for micro cracks to expand, in the case of BFRC, the fiber bears the tensile stress in the rupture section at the crack zone. Subsequently, a gradual failure after the initial crack of all the BFRC was observed which contributes to the improvement of concrete ductility performance. Structural properties of BFRC beams a) Slump test

Fresh properties of the control mix and 2% BFRC mix was tested for slump. Slump recorded for the control and 2% BFRC mixes was about 56 mm and 0 mm respectively as shown in FIGS. 5.14 and 5.15. The control mix was identified as shear slump whereas 2% BFRC mix was obtained as true slump. True slump is obtained was due to the addition of 2% bamboo fiber in the BFRC mix in which the bamboo fibres have the tendency to absorb water, hence causing the concrete less workable. b) Compressive strength

FIG. 5.16 shows the compressive strength of control mix (without fiber) and 2% fiber with 1.5-inch length BFRC mix concrete versus curing age at 3, 7, 14 and 28 days. The design mix of concrete in this research is 30 MPa. From the figure, the control mix had exceeded 30 MPa at 7 days while 2% BFRC only achieved 30 MPa after 14 days. The early strength development was found higher in the control mix compared to BFRC mix. The highest compressive strength achieved in both control mix and 2% BFRC mix was 48 MPa and 42 MPa, respectively. c) Load-deflection behavior at 28 days

FIG. 5.17 shows the load-deflection behaviour comparison of control beam and BFRC with 2% fibre beam. Similar trend of load deflection curve was observed between the two beams. At the early phase of loading, BFRC and control beams experienced first crack at about 60 kN and 80 kN, respectively. After the first crack, an increase in load was observed due to strain hardening of the reinforcement. BFRC beam managed to achieve the ultimate load of 125 kN, about 92% of the ultimate load of the control beam, 136.5 kN. Although both beams showed a similar curve trend, BFRC has higher stiffness compared to the control beam. This indicates that bamboo fibers in concrete act as linkages to provide a stronger bond between the aggregates to prevent initiation of cracks. In terms of deflection, it was noticed that BFRC beam exhibited smaller deflection, about 60% reduction in deflection compared to the control beam. Figures 5.17 and 5.18 show that beam reinforced with steel have a higher ductility compared to BFRC beam as the deflection is higher with gradual increase of load. In contrast, the BFRC beam attained the maximum load with a steep slope of strain hardening before the beam failure. BFRC beam possess a brittle failure behaviour compared to the steel reinforced concrete beam which possess higher ductility with greater plastic deformation and eventually failed in a gradual manner. Although the trend of both beams is not similar, the ultimate load achieved was almost the same. BFRC beam managed to achieve an ultimate load of 130 kN, about 95% of the ultimate load of the control beam 2. Similarly, BFRC beam 2 also exhibited small deflection, about 50% reduction of the deflection in the control beam 2. d) Crack pattern

FIG. 5.19 shows the crack pattern of control BFRG beam. It was clearly seen that a diagonal crack with a wide crack width was formed upon beam failure at both front and back of the beam. Crack pattern of 2% BFRC beam is shown in FIG. 5.20. it was found that diagonal hairline cracks with fine crack width were formed at the mid-span of the beam before failure. This indicates that bamboo fiber creates linkages and bonding with concrete, hence mitigating the formation of larger visible cracks. e) Age weathering

The BFRC was subjected to ASTM G514 aging and weathering test. FIG. 5.21 shows a comparison between weathered BFRC and unweathered BFRC specimens. From the result, it was found that the weathered BFRC1 specimen showed maximum load of about 350 N. Meanwhile, the unweathered BFRC specimens only achieved a maximum load of 290 N. Cracks were seen initiated at the early stage of loading within 0 - 0.5 mm. Upon reaching the ultimate load, the specimens failed with a sharp decrease in load. Both weathered and unweathered specimens showed similar trend of loading and unloading curve. Unweathered specimens exhibited a lower in load compared to the weathered specimens as the concrete strength increase with time. No apparent reduction in BFRC strength over the simulated prolonged used in this work because water is not absorbed into the fiber. The BFRC specimen is free of defect, hence moisture absorption to the bamboo fiber did not occur as it is protected by the concrete layer. Caution should be taken in a real life application where cracks on the BFRC may occur; hence the strengthening bamboo fiber may absorb moisture and degrading over time, thus compromising the BFRC performance. f) Crack pattern

FIG. 5.22 shows the crack pattern of weathered and unweathered BFRC specimens. Only a vertical hairline crack was traced in in the mid-span of all specimens. This shows that the effects of bamboo fibers in concrete functions to create bonding and provide linkages between aggregates in concrete that mitigate the formation of cracks.

CONCLUSION Bamboo species selection

Belong bamboo poses the highest strength and greater ductility, hence is suitable for tension reinforcement in concrete. However, Semantan bamboo is by far more consistent than that of Betong. Both Belong and Semantan bamboo are suitable to be used as compression reinforcement at the top fiber of reinforced concrete beam. Semantan bamboo has the highest decomposition temperature compared to the other species. BRC beams

The bamboo reinforced concrete, BRC beam made of 6 splints of Semantan bamboo designed by UMP has a comparable beam capacity of 46KN-59 kN as the control beams of 47KN-51 kN reinforced with 2H10 steel reinforcement, top and bottom, AS = 452 mm2. BRC beams strengthened with bamboo treated using NaOH and oxide primer showed higher ultimate load (ranging from 46 to 59 kN) about 14% higher than the control beam, steel reinforced and 25% greater than the ultimate load of BRC beam treated only with NaOH. Crack patterns of BRC beams strengthened with bamboo treated using NaOH + OP is lesser compared to control beam and BRC beam treated only by NaOH. Bending is the failure mode of BRC beams. NaOH + OP is similar to the control beam, steel reinforced. The strength of BRC beam is not affected by aging and weathering, rain, condensation and sunlight except it become brittle and low in ductility which is normal for aged concrete, BRC beam strengthened with bamboo treated using NaOH and oxide primer shows a better plastic behaviour with deflection ranging from 8 to 11 mm and less severe crack pattern not prone to vertical crack compared to BRC strengthen with bamboo treated using solely NaOH.

BFRC Beams The BFRC using 1 -inch fibre is the strongest at 51.52 MPa among all the tested fibre based on the result of compressive strength at 28 days. BFRC mixed with 2% fibre percentage with 1.5-inch fibre length was found to be the optimum percentages and have the highest compressive strength of 40.4 MPa compared to all other formulations 28 days curing. BFRC mixed with 1% 2.5-inch bamboo fibre length exhibited the highest flexural strength of 7.6 MPa, although 1 -inch and 1.5-inch fibre yielded a comparable strength of 7.4 MPa and 7.5 MPa, respectively. Test at fixed fibre length of 1.5-inch showed 2% fibre content yielded the highest flexural strength of 8.3 MPa. Optimum fibre percentage was identified as 2% for BFRC with the selected fibre length of 1.5-inch. The difference in terms of ultimate load obtained for weathered and unweathered BFRC samples is not significant, although aging cause the BFRC to be slightly stronger but less ductile.

The bamboo reinforced concrete and bamboo fibre reinforced concrete are use as a support system in a build of telecommunication sites. Unless the context requires otherwise or specifically stated to the contrary, integers, steps or elements of the invention recited herein as singular integers, steps or elements clearly encompass both singular and plural forms of the recited integers, steps or elements. Throughout this specification, unless the context requires otherwise, the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated step or element or integer or group of steps or elements or integers, but not the exclusion of any other step or element or integer or group of steps, elements or integers. Thus, in the context of this specification, the term “comprising” is used in an inclusive sense and thus should be understood as meaning “including principally, but not necessarily solely”.