CIRCUIT BOARD

FIELD OF THE INVENTION

[001] This invention leads to the Utilisation of E-waste, especially in the form of waste printed circuit board powder obtained from processed and recovered recyclable material plant as filler material in polyester resin concrete formulation using river sand, foundry sand, lignite based bottom ash and coal based bottom ash as fine aggregate and fly ash as micro filler for the wide range of construction application.

BACKGROUND OF THE INVENTION

[002] Electronic waste or e-waste describes discarded electrical or electronic devices. Used electronics which are destined for reuse, resale, recycling or disposal are also considered e-waste. Informal processing of e-waste in developing countries can lead to adverse human health effects and environmental pollution.

[003] Electronic scrap components, such as CPUs, contain potentially harmful components such as lead, cadmium, beryllium, or brominated flame retardants. Recycling and disposal of e-waste may involve significant risk to workers and communities in developed countriesand great care must be taken to avoid unsafe exposure in recycling operations and leaking of materials such as heavy metals from landfills and incinerator ashes.

World-Wide E-Wasfe

[004] Rapid changes in technology, changes in media (tapes, software, MP3), have resulted in a fast-growing surplus of electronic waste around the globe. An estimated 50 million tons of E-waste are produced each year. The USA discards 30 million computers each year and 100 million phones are disposed each year. The Environmental Protection Agency (EPA) estimates that only 15%-20% of e-waste is recycled, the rest of these electronics go directly into landfills and incinerators.

[005] The United States is the world leader in producing electronic waste.US and China produce the most e-waste of about 32% overall. China remains a major e-waste dumping ground for developed countries. And as per UNEP (United Nations Environment Programme) could rise by as much as 500 percent over the next decade in developing countries.

[006] As much as 80% of electronic waste goes out with the trash, the EPA estimates, while only about 20% is properly recycled. 300 million computers and 1 billion cell phones are put into production each year. This global e-waste is expected to continue growing 8% per year.The world produces more than 50 million tonnes of electronic waste per year and 80% of that winds up in land fill.

E-Waste in India

[007] India, which has emerged as the world’s second largest mobile market, is also the fifth largest producer of e-waste, discarding roughly 18.5 lakh tonnes of electronic waste each year. India is a signatory to Basel convention, under which trans-border movement of e-waste is restricted. Seven years ago, 50,000 tonnes of e-waste came into the country annually. But a recent report says it has been increased to 30% of waste coming inside India.

[008] India in 2014, generate about 14lakhs tonnes of e-waste. This e-waste generation could increase at the rate of 4-5% annually. The country has almost 148 registered e- waste recycling units and Karnataka had the maximum number of 52 registered dismantlers units followed by Maharashtra 24, Tamil Nadu 16, UP 16 and Haryana 14. Capacity of these units is 4.55 lakhs per annum which shows huge gap between waste generation and dismantling recycling capacity.

[009] Generally, e-waste consists of 50% of steel, 21% plastic, 14% nonferrous materials which includes gold, silver and platinum. Almost three-fourth of e-waste handled in an unscientific manner. Burning of e-waste leads to generation of fumes, increases air pollution. After recovery of items with value, remaining materials are thrown into river, drain or disposed of in solid waste dumps. Disposal in water bodies may leads to degrading of soil and water quality.

[010] India is literally being buried under a mountain of hazardous electric waste. These are imported from countries like US, south Korea, china European countries etc.., these are imported in different names to avoid the customs check and dumped after years. A recent report says, it has been increased to 30% of waste coming in. Illegal trade is driven by the relatively low cost of the shipment and high cost of treatment in developed countries.

[011] The country is literally being buried a mountain of hazardous of electronic waste and authorities are turning a blind eye. This huge quantity is actually used electronic equipment that is imported under new names to avoid custom check and dumped after few years. Study done several years ago had revealed that 50,000 tonnes of such material was being imported annually and there has been nearly 30% increased now. In the survey period from June to December 2009, a majority came from Singapore, South Korea and US and a smaller quantity came from Europe. Bringing in used items such as central processing units (CPU’s), LCD and CRT monitors, television sets, computer hard disks, mother boards or printers is illegal, but consignment containing such material carries the names of perfectly legal articles. Most of the used equipment than finds its ways to dump yards where, crude methods of segregation hurt the environment and health of those involved in disposal.

E-Waste Rules

[012] Walking up to the challenge of managing hazardous e-waste, the government of India notified revised rules to collect, dismantle and recycle all electronic and electrical waste by expanding its ambit, extending incentives to consumers who hand over waste to dealers or retailers and introducing a financial penalty clause for violation.

[013] Government of India issued e-waste (management and handling) rules, 2011 and it is modified as e-waste (management) rules 2016 in which it is addressed the collection and handling of waste only. In this invention, it is focused to utilise the E- waste especially in the form of waste printed circuit board powder obtained from processed and recovered recyclable material plant as filler material in polyester resin concrete formulation using river sand, foundry sand, lignite based bottom ash and coal based bottom ash as fine aggregate and fly ash as micro filler for the wide range of construction application of concrete pavement block of various sizes to safe guard the environment.

SUMMARY OF THE PRESENT INVENTION

[014] The present invention is polyester resin concrete comprises of organic binder with river sand as fine aggregate and fly ash as micro filler for control mix of polyester resin concrete. The printed circuit board (PCB) is obtained from the processing plant after recovering the metals and other toxic materials from the board, the remaining part is shredded in the form of fibers is used for this work. The substrate most commonly used in printed circuit boards is a glass fiber reinforced (fiberglass) with resin as an organic binder.

Toxic Materials and Safety Considerations

[015] The solder used to make electrical connections on a PCB contains lead, which is considered a toxic material. The fumes from the solder are considered a health hazard, and the soldering operations must be carried out in a closed environment. The fumes must be given appropriate extraction and cleaning before being discharged to the atmosphere. [016] Many electronic products containing PCBs are becoming obsolete within 12-18 months. The potential for these obsolete products entering the waste stream and ending up in landfills has many environmentalists concerned. Recycling efforts for electronic products include refurbishing older products and reselling them to customers that don't need, or have access to, newer, state-of-the-art electronics. Other electronics are disassembled and the computer parts are salvaged for resale and reuse in other products.

[017] In many countries in Europe, legislation requires manufacturers to buy back their used products and render them safe for the environment before disposal. For manufacturers of electronics, this means they must remove and reclaim the toxic solder from their PCBs.

[018] Waste has been an integral part of our life cycle over the past, consisting of nontoxic and toxic substances. The onset of electronic production has created a new addition to the toxic waste domain. This type of waste is not easily biodegradable and takes several centuries to decay. Disposal of electronic waste (e-waste) without incineration and land filling is the need of the hour. E-waste has different categories, most are toxic and create serious pollution problems on disposal. E-waste consists of, e.g., televisions, computers, mobile phones, printers, scanners, laptops, keyboards, remote controls, compact discs, batteries, air conditioners, and refrigerators. E-waste is piling up at a rapidly increasing rate in all major cities around the world. This has provoked a serious problem of disposal for all developed and developing countries. Although the domestic generation of e-waste continues to pose serious challenges, increasing the free trade of this waste further aggravates the problem for developing countries. According to the Associated Chambers of Commerce and Industry of India (Assocham), India generates more than 4.4 lakh tons of e-waste annually, consisting of 68% computer equipment, 12% telecommunication equipment, 8% electrical equipment, 7% medical equipment, and 5% other equipment. Only 4.5% of e-waste gets recycled because of the lack of proper infrastructure, legislation, and frameworks for recycling and disposing of electrical waste and appliances.

[019] In India, the production of concrete has increased rapidly as a result of the growth in infrastructure development. Because of this development, there is an immense consumption of natural aggregate, resulting in depletion of the natural resources. Recently, researchers have started to consider an alternative source for aggregate in concrete by using the waste material as building material. Several nations have taken up waste management as a prime area of research, especially, plastic in concrete. In recent decades, researchers have begun studying new ways to use plastic like polyethylene terephthalate (PET), high-density polyethylene (HDPE), poly vinyl chloride (PVC), and polypropylene (PP) as possible ingredients in cement mortar and concrete. [020] Even though broad research has been done on waste plastic, little has been researched on incorporating e-waste ih cement mortar and concrete. Waste e-glass material chopped from electronic grade glass yarns has been used as fine aggregate in concrete. The printed circuit board of electronic waste in powder form was used as an admixture in cement mortar, and the result shows that printed circuit board powder increases air content, improves the water retention property of fresh mortar, and decreases the bulk density of hardened mortar. Recycled high-impact polystyrene as a sand substitute in cement mortar has increased the compressive strength and decreased the splitting-tensile strength of mortar.

[021] Obsolete computers pose a significant environmental and health hazard among the e-waste, and computer equipment accounts for almost 68% of e-waste in India. The novelty of this research program is to examine the possible ways of using recycled printed circuit board waste as a filler material in polyester resin concrete and precast pavement blocks.

[022] Concrete-polymer composites are the materials made by replacing a part or all of the cement hydrate binders of conventional cement mortar or concrete with polymers and by strengthening the cement hydrate binders with the polymers. The concrete polymer composites are generally classified as polymer modified mortar, polymer mortar and polymer impregnated mortar. Polymer mortar is a composite material made from polymeric binders consisting of liquid resin such as thermosetting resin, vinyl monomers and tar modified resins. Most of the thermosetting resin and monomer systems are polymerized at ambient or room temperature. The aggregate are strongly bound to each other by the uniform polymer matrix.

[023] When resins having polymer are used by replacing cement and water shows better performance and it is called resin mortar. Resin mortar has improved intrinsic properties like mechanical strength, adhesion, resilience, impermeability and durability. It is a quick repair and strengthening material, bond strength is very high when compared with cement. It is often used as thin overlay of less than 5mm on the existing concrete flooring and on Ferro cement surfaces to improve its durability properties like chemical resistance, cavitations and abrasion resistance. There is a wide scope of using resin mortar for precast roofing components, chemical resistance pipes, special chemical and pharmaceutical industrial flooring, marine application, repair and rehabilitation of buildings and bridges etc.

[024] They can be used for Low-energy ceramic tiles, Resin Ferro composite materials, refractory items, thermal shock refractories, binders, grouts, foundry industry, radioactive and toxic waste containment. Resins used for preparing resin mortar are polyester, epoxy. When steel wire meshes are added along with resin mortar to improve the strength, it is called Resin Ferro composites. Resin Ferro composites have a very good potential for structural application. The Ferro resin mortar has improved compressive strength and helps to restrain micro-crack propagation, which improves the overall toughness of the mortar in comparison with normal cement mortar. The total porosity decreases and their by improves gas and water impermeability and consequently the durability.

1. Object of Invention

[025] India is producing huge tonnes of electronic waste behind US, China, Japan and Germany. And the recycling is also very difficult particularly fridges, washing machine and other domestic items. It is the one of the highly disposable problem around the world. In 2014, India has produced around 14 lakhs tonnes of e-waste and it is increasing at the rate of 4%-5% every year. The country has 148 registered e-waste dismantling/recycling units.

[026] Generally, e-waste consists of 50% of steel, 21% plastic, 14% non-ferrous materials which includes gold, silver and platinum. After recovery of items with value, remaining materials are thrown into river, drain or disposed of in solid waste dumps. Disposal in water bodies may leads to degrading of soil and water quality. The printed circuit board (PCB) is obtained from the processing plant after recovering the metals and other toxic materials from the board, the remaining part is shredded in the form of fibers is used for this work.

[027] In this research, the formulation of mix proportion utilizing the printed circuit board waste as a filler material in polyester resin concrete using river sand, foundry sand, lignite based bottom ash and coal based bottom ash as fine aggregate and fly ash as micro filler in polyester resin concrete by various proportions of micro filler to resin ratio (MF/R), PCB to micro filler ratio (PCB/MF), fine aggregate to PCB (FAg/PCB) ratio and the resin percentage of the formulation by optimizing the strength of the mix. The extended application parts such as precast pavement blocks and other road pavement materials. So, this will lead to safe guard the environment.

2. Statement of Invention

[028] Formulation and proportion of polyester resin mortar using, PCB as filler, river sand as fine aggregate and fly ash as micro filler using unsaturated polyester resin as a binder. The step by step method of optimizing the proportion is as below.

Collection of e-waste in the powdered form of processed printed circuit board (PCB) from the recycling and processing centre. ^■ Fineness modulus, specific gravity test, void content test etc.., are conducted for the printed circuit board as filler, river sand (4.75 to 15mm) as fine aggregate.

^■ In fly ash passing through 75 microns is also taken up for micro filler and the properties such as particles size distribution, specific gravity, void content is also studied in the laboratory.

Polyester resin is purchased from the manufacturer; properties are also obtained. The mix design using minimum void approach based on the material property starting from micro filler and resin as matrix, PCB, micro filler and resin as composite, PCB, micro filler, river sand and resin as mortar is calculated

^■ Cubes of size 100mm x 100mm x 100mm and cylinders of size 100mm diameter, 200mm height are casted and tested on the end of 7 ^th day for the compressive strength and split tensile strength of polyester resin concrete using river sand, foundry sand, lignite based bottom ash and coal based bottom ash. By varying the composition and proportion of various constituent of materials, the optimised formulation of mix design is obtained in respect of the four categories.

^■ Flexural strength is also to be carried out with the block of size 200mm x 100mm x 60mm, 200mm x 100mm x 50mm, 160mm x 150mm x 45mm are tested at the end of the 7 ^th day based on the above three categories using the above four types of concrete.

DESCRIPTION OF MATERIALS PROPERTIES

[029] The material selected and properties are obtained by various tests forcourse aggregate, fine aggregate, printed circuit board (PCB) as filler and micro fillers as listed in table 1 to 4.

• Hard broken Granite Metal Passing 20mm, retaining 4 75mm as course

aggregate.

• Locally available river sand passing through 4 75mm sieve as fine aggregate.

• Powdered Printed circuit board of passing 600 microns as filler.

• Coal based fly ash, passing 75 micron as micro filler.

• General purpose polyester resin with 38% styrene content is used. Table.1 Properties of Fine Aggregatepassing 4.75mm and retaining 90micron

Table.2 Properties of printed circuit board (PCB) as filler

Microfiller

Coal based Fly ash as micro filler. The properties is listed in table 3

Table 3 Properties of various micro filler used in resin mortar

Table.4 properties of coarse aggregatePassing 20mm and retaining 4.75mm

Resin

Commercially available unsaturated polyester resin (orthopthalic). The polyester resin obtained from VasavibalaResins Private Limited, Chennai and their properties such as physical and chemical are given in Table 5.

Table.5 Physical and Chemical properties of USP (orthopthalic)

DETAILED DESCRIPTION OF THE INVENTION

[030] The fine aggregates as river sand, powdered printed circuit board as filler, micro fillers such ash fly ash are used for this study and their respective mix proportions are arrived using the polyester resin as binding material. The various test conducted on polymer mortar to optimize the strength characteristics are described in detail.

Mix Proportion Approach

[031] The proportion of resin for the fly ash as micro filler, based on the void content of the micro filler is calculated. In general the mix design of resin concrete is based on minimum void and dense mixture based on the broken granite metal (HBG) as course aggregate, river sand, foundry sand, lignite based bottom ash and coal based bottom ash as fine aggregate and fly ash as micro filler. To provide the lowest possible polymeric binder concentrationis necessary to coat the aggregates and to fill the voids.

[032] Fly ash obtained from thermal power station was used as microfiller which pass through 75 micron, filler as Printed Circuit Board (PCB) passing 600 micron and river sand as fine aggregate. General purpose unsaturated polyester resin (orthopthalic) is used as a binder for the investigation. The properties of course aggregate (CA), fine aggregate (FAg) and micro filler (MF) studied are applied in the power’s formula. The volume fraction of materials is obtained with the property of mixtures. The minimum void approach used to obtain mix proportion for resin concrete using unsaturated polyester resin with hard broken granite metal (HBG) as course aggregate, river sand, foundry sand, lignite based bottom ash and coal based bottom ashas fine aggregate, printed circuit board (PCB) as filler and micro filler as fly ash is based on physical properties. For ail the study the powers formula is used to get mix proportion of fine aggregate, filler, micro filler and resin by weight for least void mixture. Based on the above the complete calculation of the mix proportion obtained for the various mixes for matrix (micro filler and resin), composite(PCB, micro filler, resin), mortar (different fine aggregate, PCB, fly ash and resin), concrete (course aggregate, different fine aggregate, PCB, fly ash and resin), and the compositionsare tabulated in tables6.1 , 6.2, 7.1 , 7.2, 7 3, 8.1 , 8.2, 8.3, 9.1 , 9.2, 9.3, 9.4

[033] After obtaining the above proportions, the principal issues to be looked into are obtaining a dense aggregate mixture, that is, one which has the least void content. Choosing microfiller content that is just sufficient for occupying the voids in the aggregates system without causing particle interference. To optimize the micro filler content vis-a-vis the resin content so as to obtain maximum strength. As the voids obtained is based on water and the resin having higher viscosity than water, when the coating on the surface of the aggregates is taken into account, the microfiller content is reduced by one to two ratio according to MF/R ratio. Table 6.1Mix Proportion of Matrix with Fly Ash as Micro Fillers by Volume

Based on Voids

Table 6.2 Mix Proportion of Matrix with Fly Ash Micro Fillers by Weight

Table 7.1 Mix Proportion for Polyester Resin Mortar using DifferentFine

Aggregates and LCFA as Micro Filler by Volume

Table 7.2Mix Proportion for Polyester Resin Mortar using Different Fine Aggregates and LCFA as Micro Fillers by Volume Taking into Account of the Void Content

Table 7.3Mix Proportion for Polyester Resin Mortar using Different Fine Aggregates and LCFA as Micro Fillers taking into Account the Weight of Resin

Table 8.1 Mix Proportion of Fillers (PCB) and Fly Ash as Micro Filler by volume

Table 8.2Mix Proportion of Fillers (PCB) and Fly Ash as Micro Filler

by volume taking into account of Void Content

Table 8.3 Mix Proportion of Fillers (PCB) and Fly Ash as Micro Filler by

volume taking into account of Weight of Resin

Table 9.1 Mix Proportion for Polyester Resin Concrete Using different Fine Aggregates, Filler PCB and Fly ash as Micro Filler by Volume

Table 9.2Mix Proportion for Polyester Resin Concrete Using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers by Volume Taking into Account of the Void Content

Table 9.3MΪC Proportionfor Polyester Resin Concrete UsingDifferent Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers by Volume Taking into Account of the Void Content

Table 9.4Mix Proportion for Polyester Resin Concrete Using DifferentFine Aggregates, Filler PCB and Fly Ash as Micro Fillers taking into Account the Weight of Resin

SPECIMENS PREPARED AND TESTS CONDUCTED

[034] Various mortar specimen of size 70.6x70.6x70.6 mm for compressive strength and matrix specimen of size 70.6x70.6x70.6mm were prepared with polyester resin. Flexural strength is also conducted with the mould size of 40mmx40mmx160mm at the end of the 7 ^th day based on the above three categories. After casting the specimens, they are tested for compressive strength and flexural strength based on the result, there will be an optimum percentage of resin for which maximum strength is obtained. Testing procedure is discussed in detail.

While mixing and casting the specimens, following precautions are adopted: i. Aggregates and microfiller are dried in an electric oven at 105°c for 24 hours and cooled to room temperature to ensure dry condition.

it. First the fine aggregate has to be mixed with microfiller.

iii. To the required quantity of resin obtained by the mix proportioning approach, catalyst and accelerator are added and mixed with the resin. The above modified resin is then added to aggregate mixture. After mixing thoroughly, a homogeneous mixture is obtained which is cast in the already prepared mould, to get the required specimens for conducting various tests

tv. Based on the above the complete procedure, the mix proportion for the specimen of matrix using micro filler and resin, mortar using river sand and micro filler, composite using PCB and fly ash, mortar using river sand, PCB and micro filler for the respective specimens are tabulated in table 8 to 11.

v. The optimized mix design for the above mortar with and without PCB is taken for the flexural strength specimen of size 40 x 40 x 160 m are listed in table 12

Table 10Mix Proportion for Polyester Resin Concrete Using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillersfor the Compressive Strength Specimen of Size 100 X 100 X 100mm cube

Table 11Mix Proportion for Polyester Resin Concrete Using DifferentFine Aggregates, Filler PCB and Fly Ash as Micro Fillersfor the Split Tensile Strength Specimen of Size 100mm diameter and 200mm height Cylinder

Note:

i. Polyester resin is mixed with hardener and accelerator, which is equal to 1.5% of total resin content.

ii. The accelerator should be mixed with resin first and then hardener should be added to the mix.

Table 12.1 Mix Proportion for Polyester Resin Concrete Block ofSize 200 X 100 X 50mm using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers for the Flexural Strength

Table 12.2 Mix Proportion for Polyester Resin Concrete Block ofSize 200 X 100 X 60mm using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers for the Flexural Strength

Table 12.3 Mix Proportion for Polyester Resin Concrete Block ofSize 160 X 150 X 45mm using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers for the Flexural Strength

RESULTS AND DISCUSSIONS

[035] The specimens are de molded after one day from casting and kept at room temperature for 7 days. Then specimens are weighed individually and weight is noted. Then tests are carried out for finding compressive strength and split tensile strength in the compression testing machine with 200 KN capacities. Based on the above the complete procedure, the compressive strength and split tensile strength of the specimen are obtained for the polyester resin concrete using coarse aggregate, river sand, foundry sand, lignite based bottom ash and coal based bottom ash as fine aggregate, PCB as filler, fly ash as micro filler and resin.

[036] The results of compressive strength and split tensile strength of the specimen casted, (i) Resin concrete with varying percentage of resin using, Fly Ashas micro filler and increasing the resin content for proper coating of materials (ii) Effect of fine aggregate to micro filler ratio, micro filler to resin ratio and PCB to Micro Filler ratio on the strength of resin concrete by weight and are listed in tablel O (a). The flexural strength of precast polyester resin concrete block are listed in table 12.1 (a), 12.2(a), 12.3(a) and the following inferences are drawn.

1. The mix proportion obtained by minimum void approach is based on water. The resin is used to fill the voids and so the viscosity plays an important role. As it is not possible to have a workable mix with a mix proportion actually obtained, the modified mix proportion with various micro filler, fine aggregate and resin content is suggested accordingly.

2. The compressive strength of resin concrete cubes for the river sand using fly ash as micro filler is 38.85 MPa, 59.88 MPa, 51.21 MPaand split tensile strength of concrete cylinder 3.74 MPa, 5.3 MPa, 5.69 MPa for the resin content 12 %, 14 %, 16 % the MF/R ratio 0.33, 0.27, 0.23the FAg/PCB Ratio is 9.3, 9.3, 9.3, and PCB/MF ratio 1 ,1 ,1 respectively as in table 10(a)

3. The compressive strength of resin concrete cubes for the foundry sand using fly ash as micro filler is 33.80 MPa, 41.77 MPa, 48.19 MPa and split tensile strength of concrete cylinder 2.81 MPa, 4.65 MPa, 4.16 MPa for the resin content 12 %, 14 %, 16 % the MF/R ratio 1 .02, 0.92, 0.79the FAg/PCB Ratio is 8.31 , 7.56, 7.56 and PCB/MF ratio 0.3, 0.3, 0.3 respectively as in table 10(a)

4. The compressive strength of resin concrete cubes for the lignite based bottom ash using fly ash as micro filler is 57.28 MPa, 73.25 MPa, 99.76 MPa and split tensile strength of concrete cylinder 4.32 MPa, 6.97 MPa, 6.74 MPa for the resin content 12 %, 14 %, 18 % the MF/R ratio 1.07, 0.90, 0.66 the FAg/PCB Ratio is 3.75, 3.75, 3.75 and PCB/MF ratio 0.35, 0.35, 0.35 respectively as in table 10(a)

5. The compressive strength of resin concrete cubes for the coal based bottom ash using fly ash as micro filler is 35.27 MPa, 53.07 MPa and split tensile strength of concrete cylinder 5.41 MPa, 6.08 MPa for the resin content 16 %, 18 % the MF/R ratio 0.70, 0.60 the FAg/PCB Ratio is 1 , 1 and PCB/MF ratio 0.36, 0.36 respectively as in table 10(a)

6. The mix proportion obtained based on the optimum compressive strengt s used for the precast block of size 200mm x 100mm x 50mm for flexural strength test. The flexural strength of precast concrete block for the fine aggregate of river sand, foundry sand, lignite based bottom ash, coal based bottom ash are 25.2 MPa, 18MPa, 25.2 MPa, 14.4MPa.

7. The mix proportion obtained based on the optimum compressive strength is used for the precast block of size 200mm x 100mm x 60mm for flexural strength test. The flexural strength of precast concrete block for the fine aggregate of river sand, foundry sand, lignite based bottom ash, coal based bottom ash are 21.25 MPa, 20.00 MPa, 28.56 MPa, 10.00MPa.

8. The mix proportion obtained based on the optimum compressive strength is used for the precast block of size 160mm x 150mm x 45mm for flexural strength test. The flexural strength of precast concrete block for the fine aggregate of river sand, foundry sand, lignite based bottom ash, coal based bottom ash are 23.1 1 MPa, 17.97 MPa, 23.1 1 MPa, 5.13 MPa.

Table 10(a) Compressive and Split Tensile Strength of Polyester Resin Concrete

Using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers

Table 12.1 (a) Flexural Strength for Polyester Resin Concrete Using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers for the Compressive Strength Specimen of Size 200 X 100 X 50mm block

Table 12.2 (a) Flexural Strength for Polyester Resin Concrete Using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers for the Compressive Strength Specimen of Size 200 X 100 X 60mm block

Table 12.3 (a) Flexural Strength for Polyester Resin Concrete Using Different Fine Aggregates, Filler PCB and Fly Ash as Micro Fillers for the Compressive Strength Specimen of Size 160 X 150 X 45mm block

OBSERVATION AND CRITICAL REMARKS

[037] Based on the extensive research in formulation and optimization of mix design using the recycled printed circuit board (PCB) - electronic waste as filler in polyester resin concrete with fly ash as micro filler andriver sand, foundry sand, lignite based bottom ash and coal based bottom ash as fine aggregateas fine aggregate the following are the salient conclusions:

1. To maximize the strength, it is necessary to have uniform coating on the surface of the particles. The specific surface area plays an important role so that the resin content is increased and the micro filler content is reduced.

2. The mix proportion obtained by powers formula is to be modified for the purpose of maximizing the strength, i.e. the micro filler content is to be reduced and the resin content is to be increased so as to have uniform coating on the surface and the bond is fulfilled.

3. The workable mix is the important property for the resin concrete and the flow ability, mould ability is to be improved by doing trial mixes particularly increase in resin content.

4. The MF/R ratio plays an important role in the strength of the matrix and resin concrete. The ratio is maintained between 1 and 2.5. This is adjusted based on the properties such as fineness of the materials.

5. Printed Circuit Board to Micro Filler (PCB/MF) ratio is also plays important role and it is in the range of 0.3 to 1 The maximum compressive strength of resin concrete cubes for the river sand using fly ash as micro filler is 59.88 MPa and split tensile strength of concrete cylinderis 5.3 MPa for the resin content 14 % the MF/R ratio 0.273 the FAg/PCB Ratio is 9.3 and PCB/MF ratio _. 1 respectively as in table 10{a)

The maximum compressive strength of resin concrete cubes for the foundry sand using fly ash as micro filler is 48.19 MPa and split tensile strength of concrete cylinderis 4.16 MPa for the resin content 16 % the MF/R ratio 0.79 the FAg/PCB Ratio is 7.56 and PCB/MF ratio 0.3 respectively as in table 10(a)

The maximum compressive strength of resin concrete cubes for the lignite based bottom ash using fly ash as micro filler is 99.76 MPa and split tensile strength of concrete cylinder is 6.74 MPa for the resin content 18 % the MF/R ratio 0.66 the FAg/PCB Ratio is 3.75 and PCB/MF ratio 0.35 respectively as in table 10(a) The maximum compressive strength of resin concrete cubes for the coal based bottom ash using fly ash as micro filler is 53.07 MPa and split tensile strength of concrete cylinder is 6.08 MPa for the resin content 18 % the MF/R ratio 0.60 the FAg/PCB Ratio is 1 and PCB/MF ratio 0.36 respectively as in table 10(a)

The mix proportion obtained based on the optimum compressive strength is used for the precast block of size 200mm x 100mm x 50mm for flexural strength test. The flexural strength of precast concrete block for the fine aggregate of river sand, foundry sand, lignite based bottom ash, coal based bottom ash are 25.2 MPa, 18MPa, 25.2 MPa, 14.4MPa.

The mix proportion obtained based on the optimum compressive strength is used for the precast block of size 200mm x 100mm x 60mm for flexural strength test. The flexural strength of precast concrete block for the fine aggregate of river sand, foundry sand, lignite based bottom ash, coal based bottom ash are 21.25 MPa, 20.00 MPa, 28.56 MPa, 10.00MPa.

The mix proportion obtained based on the optimum compressive strength is used for the precast block of size 160mm x 150mm x 45mm for flexural strength test. The flexural strength of precast concrete block for the fine aggregate of river sand, foundry sand, lignite based bottom ash, coal based bottom ash are 23.11 MPa, 17.97 MPa, 23.11 MPa, 5.13 MPa.