INCLUDING SAME

RELATED APPLICATION

[0001] This application claims priority to United States provisional application No. 62/675.839 filed on May 24, 2018, the content of which is incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD

[0002] The technical field relates to lightweight concrete compositions and, more particularly, fiber-reinforced concrete compositions and air-entrained concrete compositions. It also relates to fire doors including at least one of the lightweight concrete compositions.

BACKGROUND

[0003] Fire doors are doors with fire- resistance rating which can be used as part of a passive fire protection system to reduce the spread of fire and smoke between separate sections of a structure. Fire doors are generally installed with the proper fire-resistant fittings, such as the frame and door hardware, for fully complying with any fire regulations. Conventional fire doors can include a core and an internal frame (door frame) which can be made of the same material or of different materials. Some conventional fire doors include a core made of gypsum and a frame made of gypsum reinforced with organic fibers. Other types of conventional fire doors can include a core made from calcium silicate, a bonding agent and a blowing agent. Such door core is prepared in an autoclave and then dried by dehydration. The use of an autoclave requires a high amount of energy. The core, the internal frame and the door plating are joined using a glue resistant to high temperature. Gypsum and calcium silicate based fire door materials are difficult to bond using glue. The end of life of these types of door generally results from the debonding of these elements. Other examples of material that can be used to make fire door include composite, hollow-metal, metal-clad, sheet-metal, tin-clad and wood core.

[0004] The resistance to fire and very high temperatures of the fire doors can vary depending on the material used to make the core and/or the frame of the doors. Some material that present good resistance to high temperatures can however be very heavy resulting in very heavy fire doors. [0005] In addition, the fire doors should be able to maintain a good mechanical resistance even after water spraying such as when sprinklers have been activated in the case of a fire alarm.

[0006] There is a need for lightweight material to manufacture fire doors presenting fire and high temperature resistance and good mechanical resistance even after water contact.

SUMMARY

[0007] It is therefore an aim of the present invention to address the above-mentioned issues.

[0008] In accordance with an aspect, there is provided a fiber-reinforced lightweight concrete composition including calcium aluminate cement, fibers, expanded glass granulate having a diameter of at most about 2 mm, water, and optionally at least one of talc, fly ash, cenospheres, a superplasticizer and a viscosity agent.

[0009] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 44 wt% to about 82 wt% of calcium aluminate cement. In another embodiment, the fiber- reinforced lightweight concrete composition can include from about 54 wt% to about 80 wt% of calcium aluminate cement. In a further embodiment, the fiber-reinforced lightweight concrete composition can include from about 54 wt% to about 78 wt% of calcium aluminate cement.

[0010] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 3.0 wt% to about 7.0 wt% of fibers. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 3.0 wt% to about 6.0 wt% of fibers. In a further embodiment, the fiber-reinforced lightweight concrete composition can include from about 3.5 wt% to about 5.5 wt% of fibers.

[0011] In an embodiment, the fiber-reinforced lightweight concrete composition can include glass fibers, synthetic fibers, cellulose fibers and/or natural fibers. In another embodiment, the fiber-reinforced lightweight concrete composition can include polyvinylalcohol fibers and/or polypropylene fibers.

[0012] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 1 1 wt% to about 24 wt% of expanded glass granulate having a diameter of at most about 2 mm. [0013] In an embodiment, the fiber-reinforced lightweight concrete composition can include from 4.5 wt% to about 9.5 wt% of expanded glass granulate having a diameter between about 1 mm and about 2 mm, from about 4.0 wt% to about 8.5 wt% of expanded glass granulate having a diameter between about 0.5 mm and about 1 mm, and from about 2.5 wt% to about 6.0 wt% of expanded glass granulate having a diameter between about 0.25 mm and about 0.5 mm.

[0014] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 12.5 wt% to about 22.0 wt% of expanded glass granulate having a diameter of at most about 2 mm.

[0015] In an embodiment, the fiber-reinforced lightweight concrete composition can include from 5.0 wt% to about 9.0 wt% of expanded glass granulate having a diameter between about 1 mm and about 2 mm, from about 4.5 wt% to about 8.0 wt% of expanded glass granulate having a diameter between about 0.5 mm and about 1 mm, and from about 3.0 wt% to about 6.0 wt% of expanded glass granulate having a diameter between about 0.25 mm and about 0.5 mm.

[0016] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 13.0 wt% to about 22.0 wt% of expanded glass granulate having a diameter of at most about 2 mm.

[0017] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 5.0 wt% to about 9.0 wt% of expanded glass granulate having a diameter between about 1 mm and about 2 mm, from about 5.0 wt% to about 8.0 wt% of expanded glass granulate having a diameter between about 0.5 mm and about 1 mm, and from about 3.0 wt% to about 5.0 wt% of expanded glass granulate having a diameter between about 0.25 mm and about 0.5 mm.

[0018] In an embodiment, the fiber-reinforced lightweight concrete composition can include from about 21 .0 wt% to about 31.0 wt% water with respect to a dry solid content. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 22.5 wt% to about 30.0 wt% water with respect to a dry solid content. In another embodiment, the fiber- reinforced lightweight concrete composition can include from about 22.5 wt% to about 27.0 wt% water with respect to a dry solid content. In a further embodiment, the fiber-reinforced lightweight concrete composition can include from about 23.0 wt% to about 26.0 wt% water with respect to a dry solid content. [0019] In an embodiment, the fiber-reinforced lightweight concrete composition can include talc, fly ash or a mixture thereof. In another embodiment, the fiber-reinforced lightweight concrete composition can include up to about 24.0 wt% of talc, fly ash or a mixture thereof. In another embodiment, the fiber-reinforced lightweight concrete composition can include up to about 16.0 wt% of talc, fly ash or a mixture thereof. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 3.0 wt% to about 16.0 wt% of talc, fly ash or a mixture thereof. In a further embodiment, the fiber-reinforced lightweight concrete composition can include from about 5.0 wt% to about 15.5 wt% of talc, fly ash or a mixture thereof.

[0020] In an embodiment, the fiber-reinforced lightweight concrete composition can include cenospheres. In another embodiment, the fiber-reinforced lightweight concrete composition can include up to about 7.0 wt% cenospheres. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 3.0 wt% to about 6.0 wt% of cenospheres. In a further embodiment, the fiber-reinforced lightweight concrete composition can include from about 4.0 wt% to about 6.0 wt% of cenospheres.

[0021] In an embodiment, the fiber-reinforced lightweight concrete composition can include a superplasticizer. In another embodiment, the fiber-reinforced lightweight concrete composition can include up to about 1.0 wt% of a superplasticizer. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 0.2 wt% to about 0.8 wt% of a superplasticizer. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 0.3 wt% to about 0.6 wt% of a superplasticizer. In a further embodiment, the fiber-reinforced lightweight concrete composition can include from about 0.3 wt% to about 0.5 wt% of a superplasticizer.

[0022] In an embodiment, the fiber-reinforced lightweight concrete composition can include a viscosity agent. In another embodiment, the fiber-reinforced lightweight concrete composition can include up to about 0.6 wt% of a viscosity agent. In another embodiment, the fiber-reinforced lightweight concrete composition can include from about 0.2 wt% to about 0.5 wt% of a viscosity agent.

[0023] According to another aspect, there is provided an air-entrained lightweight concrete composition including a foam and/or an air-entraining agent, calcium aluminate cement, expanded glass granulate having a diameter of at most about 4 mm, water, and optionally at least one of cenospheres and a superplasticizer. [0024] In an embodiment, the air-entrained lightweight concrete composition can include from about 39.0 wt% to about 62.0 wt% of calcium aluminate cement. In another embodiment, the air- entrained lightweight concrete composition can include from about 42.0 wt% to about 57.0 wt% of calcium aluminate cement. In another embodiment, the air-entrained lightweight concrete composition can include from about 46.0 wt% to about 53.0 wt% of calcium aluminate cement. In another embodiment, the air-entrained lightweight concrete composition can include from about 44.0 wt% to about 50.0 wt% of calcium aluminate cement.

[0025] In an embodiment, the air-entrained lightweight concrete composition can include from about 30.5 wt% to about 51 wt% of expanded glass granulate having a diameter of at most about 4 mm.

[0026] In an embodiment, the air-entrained lightweight concrete composition can include from about 7.0 wt% to about 12.0 wt% of expanded glass granulate having a diameter between about 2 mm and about 4 mm, from about 9.5 wt% to about 15.5 wt% of expanded glass granulate having a diameter between about 1.0 mm and about 2.0 mm, from about 8.5 wt% to about 14.0 wt% of expanded glass granulate having a diameter between about 0.5 mm and about 1.0 mm and from about 5.5 wt% to about 9.5 wt% of expanded glass granulate having a diameter between about 0.25 mm and about 0.5 mm.

[0027] In an embodiment, the air-entrained lightweight concrete composition can include from about 34.5 wt% to about 48.0 wt% of expanded glass granulate having a diameter of at most about 4 mm.

[0028] In an embodiment, the air-entrained lightweight concrete composition can include from about 8.0 wt% to about 1 1 .0 wt% of expanded glass granulate having a diameter between about 2 mm and about 4 mm, from about 10.5 wt% to about 14.5 wt% of expanded glass granulate having a diameter between about 1.0 mm and about 2.0 mm, from about 9.5 wt% to about 13.5 wt% of expanded glass granulate having a diameter between about 0.5 mm and about 1.0 mm and from about 6.5 wt% to about 9.0 wt% of expanded glass granulate having a diameter between about 0.25 mm and about 0.5 mm.

[0029] In an embodiment, the air-entrained lightweight concrete composition can include from about 38.5 wt% to about 46.0 wt% of expanded glass granulate having a diameter of at most about 4 mm. [0030] In an embodiment, the air-entrained lightweight concrete composition can include from about 9.0 wt% to about 10.0 wt% of expanded glass granulate having a diameter between about 2 mm and about 4 mm, from about 12.0 wt% to about 14.0 wt% of expanded glass granulate having a diameter between about 1.0 mm and about 2.0 mm, from about 10.5 wt% to about 13.0 wt% of expanded glass granulate having a diameter between about 0.5 mm and about 1.0 mm and from about 7.0 wt% to about 9.0 wt% of expanded glass granulate having a diameter between about 0.25 mm and about 0.5 mm.

[0031] In an embodiment, the air-entrained lightweight concrete composition can include from about 24.0 wt% to about 45.5 wt% water with respect to a dry solid content. In another embodiment, the air-entrained lightweight concrete composition can include from about 28.5 wt% to about 42.0 wt% water with respect to a dry solid content. In another embodiment, the air- entrained lightweight concrete composition can include from about 32.0 wt% to about 38.5 wt% water with respect to a dry solid content. In a further embodiment, the air-entrained lightweight concrete composition can include from about 32.0 wt% to about 36.0 wt% water with respect to a dry solid content.

[0032] In an embodiment, the air-entrained lightweight concrete composition can include cenospheres. In another embodiment, the air-entrained lightweight concrete composition can include up to about 1 1.0 wt% cenospheres. In another embodiment, the air-entrained lightweight concrete composition can include from about 7.5 wt% to about 10.5 wt% of cenospheres. In another embodiment, the air-entrained lightweight concrete composition can include from about 8.5 wt% to about 10.0 wt% of cenospheres. In a further embodiment, the air-entrained lightweight concrete composition can include from about 9.0 wt% to about 10.0 wt% of cenospheres.

[0033] In an embodiment, the air-entrained lightweight concrete composition can include a superplasticizer. In another embodiment, the air-entrained lightweight concrete composition can include up to about 0.5 wt% of a superplasticizer. In another embodiment, the air-entrained lightweight concrete composition can include up to about 0.4 wt% of a superplasticizer. In another embodiment, the air-entrained lightweight concrete composition can include up to about 0.3 wt% of a superplasticizer. In a further embodiment, the air-entrained lightweight concrete composition can include from about 0.1 wt% to about 0.2 wt% of a superplasticizer.

[0034] In an embodiment, the air-entrained lightweight concrete composition can include at most about 0.5 wt% of an air-entraining agent. In another embodiment, the air-entrained lightweight concrete composition can include at most about 0.2 wt% of an air-entraining agent. In a further embodiment, the air-entrained lightweight concrete composition can include a fatty acid based air-entraining agent.

[0035] In an embodiment, the air-entrained lightweight concrete composition can include from about 20 vol% to about 40 vol% of the foam, based on the volume of the composition.

[0036] In an embodiment, the foam included in the air-entrained lightweight concrete composition can include a mixture of a foaming agent and water and the foaming agent can represent from about 0.1 vol% to about 1 .0 vol% of the foam volume.

[0037] In an embodiment, the air-entrained volume in the air-entrained lightweight concrete composition can range from about 5.0 vol% and about 50.0 vol%. In another embodiment, the air- entrained volume in the air-entrained lightweight concrete composition can range from about 10.0 vol% and about 40.0 vol%. In a further embodiment, the air-entrained volume in the air-entrained lightweight concrete composition can range from about 10.0 vol% and about 35.0 vol%.

[0038] In an embodiment, the fiber-reinforced lightweight concrete composition and/or the air- entrained lightweight concrete composition can include calcium aluminate cement including at least about 30 wt% alumina. In another embodiment, the calcium aluminate cement in the fiber- reinforced lightweight concrete composition and/or the air-entrained lightweight concrete composition, can include from about 36 to about 60 wt% alumina. In a further embodiment, the calcium aluminate cement in the fiber-reinforced lightweight concrete composition and/or the air- entrained lightweight concrete composition, can include from about 36 to about 42 wt% alumina.

[0039] In an embodiment, the fiber-reinforced lightweight concrete composition and/or the air- entrained lightweight concrete composition can include cenospheres having a diameter of at most about 300 pm and a volumetric mass density of about 0.7 kg/liter. In another embodiment, the cenospheres included in the fiber-reinforced lightweight concrete composition and/or the air- entrained lightweight concrete composition can include about 28 to about 34 wt% alumina and about 55 to about 60 wt% silica.

[0040] According to another aspect, there is provided a fiber-reinforced lightweight concrete obtained from the fiber-reinforced lightweight concrete composition as defined herein. [0041] In an embodiment, the fiber-reinforced lightweight concrete can be characterized by a compressive strength of from about 24 to about 30 MPa.

[0042] In an embodiment, the fiber-reinforced lightweight concrete can be characterized by a volumetric mass density ranging from about 1200 to about 1400 kg/m ³ .

[0043] According to another aspect, there is provided a fire door frame including the fiber- reinforced lightweight concrete as defined herein.

[0044] According to another aspect, there is provided an air-entrained lightweight concrete obtained from the air-entrained lightweight concrete composition as defined herein.

[0045] In an embodiment, the air-entrained lightweight concrete can be characterized by a compressive strength of from about 1 to about 6 MPa.

[0046] In an embodiment, the air-entrained lightweight concrete can be characterized by a volumetric mass density ranging from about 400 to about 800 kg/m ³ . In another embodiment, the air-entrained lightweight concrete can be characterized by a volumetric mass density ranging from about 500 to about 750 kg/m ³ .

[0047] According to another aspect, there is provided a fire door core portion including the air-entrained lightweight concrete as defined herein.

[0048] According to another aspect, there is provided a fire door including the fire door frame as defined herein surrounding and bonded to the fire door core portion as defined herein.

[0049] In this specification, the term“concrete” is intended to mean“a mixture of a paste and aggregates”. The term“fiber-reinforced concrete” is intended to mean“a concrete containing fibrous material to increase its structural integrity”. The term“air-entrained concrete” is intended to mean “concrete that contains an intentional amount of air in the form of microscopic air bubbles”. The term“paste” is intended to mean“a mixture of binder (e.g. cement, talc and/or fly ash), water and air”.

[0050] The present document refers to a number of documents, the contents of which are hereby incorporated by reference in their entirety. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Fig. 1 is a graph showing the relationship between refractoriness and chemical composition of calcium aluminate cements. This graph is disclosed as Figure 4.2 entitled “Relationship between refractoriness and chemical composition of calcium aluminate cements” in Advanced Concrete Technology, ed. John Newman, Ban Seng Choo, Elsevier 2003.

[0052] Fig. 2 represents a fire door made of lightweight concrete in accordance with an embodiment.

[0053] Fig. 3 is an exploded view of the fire door represented in Fig. 2, showing the core portion, the frame portion and the external veneer.

[0054] Fig. 4 is a zoomed view of the top left of Fig. 3 showing a portion of the core, a portion of the frame, a portion of the veneer of the fire door and a door hinge which can be used to mount the door to a wall framework.

DETAILED DESCRIPTION

[0055] It will be noted that, throughout the appended drawings, like features are identified by like reference numerals.

[0056] Moreover, although the embodiments of the fire door and corresponding parts thereof consist of certain geometrical configurations as explained and illustrated herein, not all of these components and geometries are essential and thus should not be taken in their restrictive sense. It is to be understood, as also apparent to a person skilled in the art, that other suitable components and cooperation therebetween, as well as other suitable geometrical configurations, may be used for the fire door, as will be briefly explained herein and as can be easily inferred therefrom by a person skilled in the art. Moreover, it will be appreciated that positional descriptions such as“above”,“below”,“left”,“right” and the like should, unless otherwise indicated, be taken in the context of the figures and should not be considered limiting.

[0057] In the present description, the same numerical references refer to similar elements. Furthermore, for the sake of simplicity and clarity, namely so as to not unduly burden the figures with several references numbers, not all figures contain references to all the components and features, and references to some components and features may be found in only one figure, and components and features of the present disclosure which are illustrated in other figures can be easily inferred therefrom. The embodiments, geometrical configurations, materials mentioned and/or dimensions shown in the figures are optional and are given for exemplification purposes only.

[0058] To provide a more concise description, some of the quantitative expressions given herein may be qualified with the term "about". It is understood that whether the term "about" is used explicitly or not, every quantity given herein is meant to refer to an actual given value, and it is also meant to refer to the approximation to such given value that would reasonably be inferred based on the ordinary skill in the art, including approximations due to the experimental and/or measurement conditions for such given value.

[0059] In the present description, the term“about” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e. the limitations of the measurement system. It is commonly accepted that a 10% precision measure is acceptable and encompasses the term“about”.

[0060] In the present description, when a broad range of numerical values is provided, any possible narrower range within the boundary of the broader range is also contemplated. For example, if a broad range value of from 0 to 1000 is provided, any narrower range between 0 and 1000 is also contemplated. If a broad range value of from 0 to 1 is mentioned, any narrower range between 0 and 1 , i.e. with decimal value, is also contemplated.

[0061] In the present description, an embodiment is an example or implementation of the invention. The various appearances of “one embodiment,” “an embodiment” or “some embodiments” do not necessarily all refer to the same embodiments. Reference in the specification to “some embodiments”, “an embodiment”, “one embodiment” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the invention. The terms “implementation” and “embodiment” are used interchangeably in the specification.

[0062] Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment. [0063] It is to be understood that the phraseology and terminology employed herein is not to be construed as limiting and are for descriptive purposes only.

[0064] The principles and uses of the teachings of the present invention may be better understood with reference to the accompanying description, figures and examples.

[0065] It is to be understood that the details set forth herein do not construe a limitation to an application of the invention.

[0066] Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in embodiments other than the ones outlined in the description above.

[0067] It is to be understood that, where the claims or specification refer to“a” or“an” element, such reference is not be construed that there is only one of that element. If the specification or claims refer to“an additional” element, that does not preclude there being more than one of the additional element.

[0068] It is to be understood that, where the specification states that a component, feature, structure, or characteristic“may”,“might”,“can” or“could” be included, that particular component, feature, structure, or characteristic is not required to be included.

[0069] The term“method” may refer to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the art to which the invention belongs.

[0070] The descriptions, examples, methods and materials presented in the claims and the specification are not to be construed as limiting but rather as illustrative only.

[0071] Meanings of technical and scientific terms used herein are to be commonly understood as by one of ordinary skill in the art to which the invention belongs, unless otherwise defined.

[0072] The present invention may be implemented in the testing or practice with methods and materials equivalent or similar to those described herein. [0073] There is provided lightweight concrete compositions including aluminous cement (or high-alumina cement or calcium aluminate cement or Fondu cement). A“lightweight concrete” can represent a concrete presenting a unit weight or density, which generally ranges from about 320 to about 1920 kg/m ³ , according to the ACI Committee 213 Guide for Structural Lightweight Aggregate Concrete (ACI 213, 2001 ). Lightweight concretes can be divided into three different categories in terms of their strength range, including low-density concretes (0.7-2.0 MPa), moderate-strength concretes (7-14 MPa) and structural concretes (17-63 MPa). The density of these concretes can be in the range of 300-800 kg/m ³ , 800-1350 kg/m ³ and 1350-1920 kg/m ³ respectively.

[0074] More particularly, there is provided fiber-reinforced lightweight concrete compositions, wherein fibers are added to the mixture. In some embodiments, the aluminous cement can be combined with talc or fly ashes, as binder. There is also provided air-entrained lightweight concrete compositions.

[0075] Calcium aluminate cements have a high alumina content. Typically, calcium aluminate cements include at least about 30 wt% of alumina. In comparison, Portland type cements generally contain less than 10 wt% of alumina. To include alumina in the cement, bauxite is typically added during the manufacture of the cement, and typically, a calcium aluminate cement is formed by the sintering of clinkers of limestone and bauxite, with small amounts of silica and other materials such as titanium oxide and iron oxide. Further description of calcium aluminate cements is provided in US. Pat. No. 4,033,782, the entire disclosure of which is incorporated herein by reference.

[0076] Unlike Portland type cements, calcium aluminate cements produce a binder having an excellent stability at high temperature (1200°C). Calcium aluminate cements (CAC) are classified by their alumina content, as shown in Table 1 below. A calcium aluminate cement having a higher alumina content can resist higher temperatures, as shown in Figure 1 . However, these calcium aluminate cements are typically more expensive. [0077] Table 1 : Typical analyses of calcium aluminate cements (CAC) compared to Portland cement. ( Advanced Concrete Technology, ed. John Newman, Ban Seng Choo, Elsevier 2003)

[0078] In one embodiment, the lightweight concrete compositions described herein, include low-range CACs, which can resist temperatures of at least 1000°C. The use of such low-range CAC in the lightweight concrete compositions can be advantageous in terms of costs. However, lightweight concrete compositions could also be prepared using mid-range or high-range CACs as described in Table 1 . In some embodiments, one could use a mixture of low, mid and/or high- range CACs. In some embodiments, the lightweight concrete compositions can be prepared using CACs having an alumina content ranging from about 36 to about 82 wt%, or from about 36 to about 75 wt%, or from about 36 to about 60 wt%, or from about 36 to about 50 wt%,or from about 36 to about 42 wt%.

[0079] In addition to the CAC, the lightweight concrete compositions, i.e. the fiber-reinforced and the air-entrained lightweight concrete compositions, also include aggregate (particulate material), i.e. the granular skeleton of the lightweight concrete compositions, and, more particularly, lightweight aggregate. The lightweight aggregate can be supplied from post- consumer recycling. For instance, and without being limitative, lightweight aggregate made of post-consumer recycled glass can be used.

[0080] In a non-limitative embodiment, the aggregate of the lightweight concrete compositions includes expanded glass granulate. By“expanded glass granulate”, one can refer to glass that has been milled, mixed with foaming agents and melted down in extremely high temperature. The expanded glass granulate can be produced from recycled glass, as it is known in the art. For instance, the Poraver® (Ontario) expanded glass granulate can be used. In an embodiment, the expanded glass granulate can include particles having a diameter of about 20 mm maximum. However, the maximum diameter of the particles or grains can be selected based on the intended applications. For instance, in some non-limitative implementations, the expanded glass granulate can include particles having a diameter smaller than about 15 mm, or smaller than about 10 mm, or smaller than about 8 mm. In some implementations, the diameter of the expanded glass granulate can be at most about 4 mm or at most about 2 mm. In some embodiments, the expanded glass granulate can include particles having a diameter ranging from about 2 mm to about 4 mm. In other embodiments, the particles can have a diameter ranging between about 0.25 to about 4 mm and a dry volumetric mass density between about 0.3 and about 0.6 kg/liter. It is also appreciated that other expanded glass granulates can be used such as, and without being limitative, the expanded glass granulate supplied by Quietstone.

[0081] In some embodiments, the granular skeleton of the lightweight concrete compositions can also include ceramic microspheres (or cenopheres). Cenospheres are lightweight, inert, hollow spheres made largely of silica (S1O ₂ ) and alumina (AI ₂ O ₃ ) and filled with air or inert gas. They are typically produced as a byproduct of coal combustion at thermal power plants. For instance, and without being limitative, the ceramic microspheres LS300 manufactured by Cenostar (USA) can be used in the present lightweight concrete compositions. In some embodiments, the cenospheres can have a diameter of at most about 300 pm, e.g. varying from about 10 to about 300 pm, and a volumetric mass density of about 0.7 kg/liter. In some embodiments, the cenospheres can include about 28 to about 34 wt% alumina and about 55 to about 60 wt% silica.

[0082] In an embodiment, the granular skeleton of the lightweight concrete compositions includes a mixture of expanded glass granulate and cenospheres. The content of each one of the expanded glass granulate and cenospheres can be selected to obtain a particle size distribution curve resulting in a reduction of the total volume of the inter-particle voids in the granular skeleton. For example, Fuller-Thompson Andreasen-Andersen, or Funk-Dinger particle size distribution curves can be used. In an embodiment, the granular skeleton can be substantially free of cenopheres and include solely expanded glass granulate.

[0083] In some implementations, the lightweight concrete compositions can be fiber- reinforced to provide fiber-reinforced lightweight concrete compositions. Different type of reinforcement fibers can be used in the compositions. The reinforcement fibers can be any fibrous material capable of increasing the structural integrity of the concrete. The fibrous material can contain short discrete fibers that can be uniformly distributed and randomly oriented. Examples of fibers can include glass fibers, synthetic fibers, cellulose fibers and natural fibers.

[0084] In a particular embodiment, polyvinyl alcohol (PVA) fibers or polypropylene fibers can be used as reinforcement fibers in the lightweight concrete compositions. In some embodiments, one can use a mixture of polyvinyl alcohol and polypropylene fibers in the lightweight concrete compositions. In a non-limitative embodiment, the length of the PVA fibers can be between about 12 mm and about 18 mm and their diameter can be between about 100 pm and about 200 pm. In another non-limitative embodiment, the polypropylene fibers can have a length between about 50 mm and about 55 mm, for instance about 54 mm, a width of about 1 mm and height of about 0.5 mm. In some embodiments, the PVA fibers can have a 12 mm length and the polypropylene fibers can have a 54 mm length.

[0085] In some implementations, the fiber-reinforced lightweight concrete compositions can also include talc powder. In an embodiment, the talc powder can be characterized by a volumetric mass density of about 2.7 kg/liter and a particle diameter ranging between 5 and 70 micrometers.

[0086] In an alternative embodiment, the talc powder can be replaced, entirely or partially, by fly ash, class F, also known as "pulverized fuel ash", which is a cool combustion product. Fly ash can be characterized by a volumetric mass density of about 2.3-2.4 kg/liter and particles having a mean diameter ranging between about 10 and about 40 pm.

[0087] In some implementations, the fiber-reinforced lightweight concrete compositions can also include a viscosity agent. The viscosity agent can be present in the compositions in a quantity of from about 0.5 to about 2 wt% with respect to the total water content of the composition. In some implementations, the viscosity agent can be present in the compositions in a quantity of about 0.6 wt% maximum, for instance from about 0 to 0.6 wt%, or from 0 to 0.5 wt% or from 0.2 to 0.5 wt% based on the weight of the composition. An example viscosity agent that can be used in the compositions can be Welan gum. However, any other viscosity agent known in the field of concrete can be used.

[0088] The fibers can be added to increase the mechanical properties of the concrete and, more particularly, the pull-out resistance. The talc, or the fly ash, can be added to increase the tenderness and homogeneity of the concrete. Furthermore, their addition can lower the manufacturing cost and valorize industrial waste. [0089] In some implementations, the lightweight concrete compositions can include an air- entraining admixture (or air-entraining agent) to form air-entrained lightweight concrete compositions, as will be described in more details below. According to ASTM C260, an air- entraining admixture is a material that can be used as an ingredient of concrete, added to the batch immediately before or during its mixing, for the purpose of entraining air. Examples of air- entraining agent (pore-forming agents) can include surface-active substances, substances that produce gas pores or gas bubbles in the not-yet-set concrete by triggering a chemical reaction. Examples of air-entraining agents can include fatty acids. In some implementations, the air- entrained lightweight concrete compositions can include from 0 to about 0.5 wt% of air-entraining agent. In another implementation, the air-entrained lightweight concrete compositions can include from 0 to about 0.4 wt%, from 0 to about 0.3 wt%, or from 0 to about 0.2 wt%, or from 0.1 to about 0.2 wt% of air-entraining agent.

[0090] In some implementations, the air-entrained lightweight concrete compositions can also include a foaming agent, such as synthetic surfactant. The foaming agent can be present in the compositions in a quantity of about 0.1 wt% maximum, for instance from about 0 to 0.08 wt%, or from 0.03 to 0.07 wt% or from 0.04 to 0.06 wt%. In a particular embodiment, the product Aerlite- iX™ commercialized by Aerix Industries can be used as foaming agent. However, any other foaming agent known in the field can be used.

[0091] In some implementations, the lightweight concrete compositions, either fiber- reinforced or air-entrained, can also include a superplasticizer, as it is known in the art of concrete. A superplasticizer can be added to the compositions for improving homogeneity of the concrete if required. Examples of superplasticizers can include polynaphthalene-based or polycarbonate- based admixtures. In some implementations, a polycarboxylate based superplasticizer can be used in the fiber-reinforced concrete composition and a polynaphtalene-based superplasticizer can be used in the air-entrained concrete composition. The superplasticizer can be used in very small quantities, for example not more than 1 wt% of the total weight of the lightweight concrete composition. In some embodiments, the superplasticizer can be added in a quantity of from 0 to 0.8 wt%.

[0092] It is appreciated that the concrete mechanical properties, such as its compression strength, can be selected and adjusted in accordance with the intended industrial application. Typically, the compression strength is a function of the concrete volumetric mass density. Therefore, a lighter concrete will typically show lower mechanical properties.

[0093] The two embodiments of lightweight concrete compositions, i.e. the fiber-reinforced and the air-entrained lightweight concretes, can be manufactured using usual concrete production equipment and tools. The lightweight concretes can be prepared by mixing together the concrete constituents (mineral aggregate, the CAC binder, the chemical additives, the fibers (if any), the air- entrained admixture (if any), and water) into a standard concrete mixer or a mortar mixture. As will be described in more details below, the air-entrained lightweight concrete can be obtained by adding an air-entraining admixture into the mixer and mixing the air-entraining admixture together with the other concrete constituents. Then, the mixture can be poured/placed into molds under vibrations for compaction. It can be unmolded in less than 24 hours due to its mechanical properties. Following unmolding, the concrete pieces can be maintained in a humid environment, for instance between 80 and 100% relative humidity (R.H.), for up to seven (7) days for curing. Optionally, the manufacturing process can end with a drying step wherein the concrete pieces are maintained at a temperature between about 20°C to about 100°C during a few days. For instance, in an embodiment, the concrete pieces are maintained at about 60°C to about 70°C during about three days. The manufacturing process does not require heat treatment inside an autoclave or at a temperature higher than 100°C, thereby reducing the energy consumption during the concrete production.

[0094] In a non-limitative embodiment, the lightweight concrete compositions, i.e. the fiber- reinforced and the air-entrained lightweight concretes, can be used as building materials for a fire door, such as the one shown in Figures 2 to 4, either as fire door frame (or internal frame) or core portion, as will be described in more details below. According to the technical standard (i.e. the norm or requirement), fire doors should be designed to stand a temperature rise between about 23°C and 1000°C within 90 minutes, followed by an immediate water spraying, intended to simulate watering by firehose(s).

[0095] In additional to its thermal performance, a fire door should withstand a physical endurance test, which consists of 325 000 opening/closing cycles ( cycle-slam test) in accordance with the industry standard WDMA.

[0096] Conventional fire doors that can withstand a temperature rise between about 23°C and 1000°C within 90 minutes, can be made of various materials. The core of conventional fire door is typically made of panels having a thickness of about 35 mm. The core can be made of gypsum or from a mixture of calcium silicate with a binding agent and a foaming agent that is treated in an autoclave and then dried to remove water. These core panels are characterized by a low volumetric mass density, i.e. < 700 kg/m ³ . The core portion mostly fills the internal volume of the fire door. The core portion material should be selected for its refractory properties, while the requirements for the structural properties are relatively low.

[0097] The door frame (or internal frame) for the fire door can be made of a different material than the core. The door frame defines the door perimeter. In a non-limitative embodiment, the internal frame includes four frame members, each one having a square cross-section. In an embodiment, the cross-section is about 35 x 35 mm. Typically, fire door frames are not made of concrete. The internal frame has a structural functionality since it must receive hinge screws and other elements that are secured to the door (automatic door closers, handles, panic bar, etc.).

[0098] Figs. 2 to 4 show a fire door that can be manufactured using the lightweight concrete compositions according to an embodiment. The fire door 10 can include a frame 12 (also referred to as“internal frame”) and a core panel 14, which once assembled, form the door body. A veneer 16 can cover both surfaces of the door body.

[0099] The door frame 12 can include four portions, a top, a bottom and two side portions, that can be bonded to the core panel 14 to form the door body. The door frame can be bonded to the core panel using suitable heat-resistant adhesives. Examples of such heat-resistant adhesives can include polyvinylacetate based adhesives, ureaformaldehyde based adhesives, polyurethanes, or sodium silicate, to name a few.

[00100] The veneer 16 that covers each surface of the door body can include a thin wood or wood-based veneering. The thickness of the veneer can be very small, for example between about 2 to about 3 mm. In addition to its aesthetic function, this thin veneer can promote the cohesion of the internal components of the fire door, i.e. the door core and the door frame. The internal frame 12 can receive hinge screws to attach door hinges to the door body.

[00101] In some implementations, fiber-reinforced lightweight concrete compositions as disclosed herein can used to make the door frame 12 and air-entrained lightweight concrete compositions as disclosed herein can used to make the door core 14. [00102] In some implementations, the concrete used for the doorframe, which can be obtained from the lightweight concrete compositions, can be characterized by a volumetric mass density below about 1400 kg/m ³ . In other implementations, the lightweight concrete used for the door frame can be characterized by a compression strength between about 24 MPa and about 30 MPa.

[00103] In one embodiment, the door frame can be made of fiber reinforced lightweight concrete having a volumetric mass density of from about 1200 to about 1350 kg/m ³ . In another embodiment, the core portion of the fire door can be made of air entrained lightweight concrete having a volumetric mass density of from 400 to about 800 kg/m ³ . In some embodiments, the core portion of the fire door can be made of air entrained lightweight concrete having a volumetric mass density of from about 500 to about 750 kg/m ³ .

FIBER-REINFORCED LIGHTWEIGHT CONCRETE COMPOSITION

[00104] There is provided fiber-reinforced lightweight concrete compositions having refractory properties. The fiber-reinforced lightweight concrete compositions can have a volumetric mass density (hereinafter“density”) ranging between about 1200 and about 1400 kg/m ³ .

[00105] The fiber-reinforced lightweight concrete compositions include at least calcium aluminate cement (CAC), expanded glass granulates, fibers and water. In some implementations, the fiber-reinforced lightweight concrete compositions can further include talc and/or fly ash, cenopsheres, a superplasticizer and/or a viscosity agent. These constituents can be present in the fiber-reinforced lightweight concrete compositions in various proportions.

[00106] As previously mentioned, the granular skeleton of the fiber-reinforced lightweight concrete compositions can include a mixture of expanded glass granulate and cenospheres. The content of each one of the expanded glass granulate and cenospheres can be selected to obtain a particle size distribution curve reducing the total volume of the inter-particle voids in the granular skeleton. In some implementations, the expanded glass particles or the fiber-reinforced lightweight concrete can have a diameter ranging between about 0.25 to about 2 mm. In some embodiments, the relative content of expanded glass granulate and cenospheres, in the granular skeleton for the fiber-reinforced lightweight concrete compositions, can be as summarized in Table 2 below. [00107] Table 2 : Relative content of expanded glass granulate and cenospheres used in the fiber-reinforced lightweight concrete compositions

[00108] In one embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 3 below.

[00109] Table 3

[00110] In the present description, the sum of the weight percentages of all the solid constituents of the lightweight concrete compositions is 100 wt% and the content of water added to the lightweight concrete compositions is provided in weight percentage (wt%) with respect to the content of all the solid constituents (i.e., the dry solid matter) present in the compositions.

[00111] In another embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 4 below. [00112] Table 4

[00113] In another embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 5 below.

[00114] Table 5

[00115] In another embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 6 below. [00116] Table 6

[00117] In another embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 7 below.

[00118] Table 7

[00119] In another embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 8 below. [00120] Table 8

[00121] In a further embodiment, the fiber-reinforced lightweight concrete compositions can include the constituents in the proportions mentioned in Table 9 below.

[00122] Table 9

[00123] In an embodiment, the fiber-reinforced lightweight concrete compositions can have a compressive strength between about 24 and about 30 MPa. [00124] The fiber-reinforced lightweight concrete characterized by the above-described compositions can stand temperatures as high as 1000 °C. After reaching a temperature of about 1000°C, it can stand a water quench, i.e. sprayed with water, while maintaining good mechanical properties, such as a compressive strength between about 7 and about 9 MPa.

[00125] In an embodiment, the lightweight concrete compositions can be shaped using tools typically used to cut, pierce, and shape wood.

AIR-ENTRAINED LIGHTWEIGHT CONCRETE COMPOSITION

[00126] In accordance with another embodiment, there is provided an air-entrained lightweight concrete composition which can present a density ranging from about 400 to about 800 kg/m ³ and, in a particular embodiment, from about 500 to about 750 kg/m ³ . As for the fiber-reinforced lightweight concrete composition, the air-entrained lightweight concrete composition can stand temperatures as high as 1000°C. After reaching a temperature of about 1000°C, it can stand a water quench without substantial cracking.

[00127] The air-entrained lightweight concrete compositions can have a compressive strength between about 1 and about 6 MPa. After being heated up to about 1000°C followed by water spraying, the concrete resulting from the air-entrained lightweight concrete compositions can maintain between about 45% and about 75% of its mechanical resistance.

[00128] The air-entrained lightweight concrete compositions include at least calcium aluminate cement (CAC), expanded glass granulates, at least one of a foam and air-entraining agent, and water. In some implementations, the air-entrained lightweight concrete compositions can further include cenopsheres and/or a superplasticizer. These constituents can be present in the air- entrained concrete compositions in various proportions.

[00129] The foam and/or the air-entraining agent are used to provide the desired gaseous phase in the form of microscopic air bubbles, to the air-entrained lightweight concrete compositions. The air-entraining agent, which can be either a liquid or solid product, allows the creation of air bubbles during the mixing of all the other concrete ingredients. The foam can be obtained from a mixture including a foaming agent and water which can pass through a foam generator to produce a stable foam, comparable to shaving cream. The stable foam can then be blended with the other concrete ingredients to produce the desired density for the air- entrained lightweight concrete compositions. The foam is said to be stable since the volume of air is stable during the entire manufacturing process (mixing with concrete, placing and finishing operations).

[00130] In some implementations, the air-entraining agent can be used in an amount ranging from 0 to about 0.5 wt% of the total weight of solid matter of the composition. In other implementations, the air-entraining agent can be used in an amount ranging from 0 to about 0.4 wt%, or from 0 to about 0.2 wt%.

[00131 ] In another implementation, the foam obtained from the mixture of the foaming agent and water, can represent from about 20 vol% to about 40 vol% of the volume of the final composition. The amount of foaming agent used to make the foam can be selected depending on the type of foaming agent and a person skilled in the art would be able to adapt the quantity of foaming agent to obtain a foam of desired density. In some implementations, the amount of foaming agent can represent from about 0.1 vol% to about 1 .0 vol% based on the foam volume.

[00132] In some implementations, the air-entrained lightweight concrete compositions can include a mixture of expanded glass granulate and cenospheres for which the content of each one of the expanded glass granulate and cenospheres can be selected to obtain a particle size distribution curve reducing the total volume of the inter-particle voids in the granular skeleton. For the air-entrained lightweight concrete, all the particles have a diameter below about 20 mm. In some implementations, the diameter can be below about 8 mm. More particularly, the expanded glass particles can have a diameter ranging between about 0.25 to about 4 mm, slightly coarser than for the fiber-reinforced lightweight concrete compositions. Furthermore, the air-entrained lightweight concrete compositions are free of talc or fly ash, as binder. It is also generally free of fibers.

[00133] In some embodiments, the relative content of expanded glass granulate and cenospheres, in the granular skeleton for the air-entrained lightweight concrete compositions, can be as summarized in Table 10 below. [00134] Table 10: Relative content of expanded glass granulate and cenospheres used in the air-entrained lightweight concrete compositions

[00135] In a non-limitative embodiment, the air-entrained lightweight concrete composition can be used as door core for a fire door, as shown in Figs. 2 and 3.

[00136] In one embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 1 1 below.

[00137] Table 11

[00138] In another embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 12 below. [00139] Table 12

[00140] In another embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 13 below.

[00141] Table 13

[00142] In another embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 14 below.

[00143] Table 14

[00144] In another embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 15 below.

[00145] Table 15

[00146] In another embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 16 below.

[00147] Table 16

[00148] In another embodiment, the air-entrained lightweight concrete compositions can include the constituents in the proportions mentioned in Table 17 below.

[00149] Table 17

[00150] The above-described lightweight concrete compositions can be prepared using conventional concrete manufacturing equipment. The manufacturing process is advantageous since it does not require high temperature treatment (i.e. > 100°C) once the concrete composition has been molded to the desired form.

EXAMPLES

[00151] Fiber-reinforced lightweight concrete compositions, air-entrained lightweight concrete compositions and fire doors made therefrom, were prepared and tested, as will be detailed below.

[00152] In the examples, a low-range CAC commercialized under the name Fondu™ by the company Kerneos, was used to make the lightweight concrete compositions. This CAC has an alumina content between about 36 wt% and about 42 wt% and is characterized by the chemical constituents summarized in Table 18 and the mechanical properties detailed below.

[00153] Table 18: Chemical constituents of the low-range CAC used in the examples

Blaine fineness: 3600-4400 cm ² /g (ASTM C204)

Physical properties (using EN-196 sand mortar)

• Flow at 15 min: > 30% (ASTM C1437)

• Vicat Initial Set: > 120 min.

• Vicat Final Set: > 230 min.

Modified ASTM C191 - Needle weight is 1000 g, needle diameter is 1.16 mm, samples immersed in water.

• Compressive strength (ASTM C349)

o 6 hr ³ 2900psi (20.0 MPa)

o 24 hr ³ 4900psi (33.8 MPa)

[00154] Even though the examples were carried out using low-range CACs, in alternative embodiments, mid-range and high-range CACs can also be included in the lightweight concrete compositions. For instance, and without being limitative, a mid-range CAC having an alumina content of about 55-59 wt% (with a CaO content between about 27.0 to 36.0 wt%) can be used. [00155] In the following examples, Poraver® (Ontario) expanded glass granulate was used in the lightweight concrete compositions.

[00156] LS300 grade cenospoheres manufactured by Cenostar (USA) were used. These cenospheres have a diameter smaller than 300 pm and a volumetric mass density of about 0.7 kg/liter.

[00157] Talc powder was characterized by a volumetric mass density of about 2.7 kg/liter and a particle diameter ranging between 5 and 70 pm. Class F Fly ash from the company Holcim was used and was characterized by a volumetric mass density of about 2.3-2.4 kg/liter and particles having a mean diameter ranging between about 10 to about 40 pm.

[00158] The PVA fibers used in the examples are commercialized under the name RF 350 by the company Kuraray. These PVA fibers have a length of 12 mm. The polypropylene fibers are commercialized under the name MAC 2200 CB by BASF. These polypropylene fibers have a length of 54 mm, a width of 1 mm and a height of 0.5 mm.

[00159] A polycarboxylate based superplasticizer commercialized under the name Plastol™ 6400 by the company Euclid, was used in the fiber-reinforced lightweight concrete compositions. A polynaphtalene-based superplasticizer commercialized under the name Eucon 37™ by the company Euclid, was used in the air-entrained lightweight concrete compositions.

[00160] The viscosity agent used in the fiber-reinforced lightweight concrete compositions was a Welan gum-based admixture commercialized under the name Visctrol™ by the company Euclid.

[00161] The air-entraining agent used in the air-entrained lightweight concrete compositions was a fatty acid based air-entraining agent commercialized under the name Eucon Air mac 12™ by the company Euclid.

[00162] The pull-out tests which can also be referred to as the“screw withdrawal resistance” tests were performed according to the Test Method for Determining the Screw Holding Capacity of Wood Doors, WDMA T.M. 10-14.

[00163] The sawability was tested as described as follows. An electric circular saw with a carbide blade 305 mm in diameter, 4.2 mm thick and having 80 teeth was used. The circular saw cut a thickness of 75 mm of concrete at a constant speed of 4 m/min. The wear of the teeth was then analyzed using a microscope. The ability of the concrete to be sawn is expressed as the percentage of wear for a linear foot (305 mm) of sawn concrete. [00164] The Cycle-Slam Test was performed according to Test Method for Determining the Physical Endurance of Wood Doors & Associated Hardware Connections under Accelerated Operating Conditions, WDMA T.M. 7-14. This test method determines the performance of a door as it swings in its opening. The test is designed to accelerate the actual operating conditions. The test indicates the effects of hard impacts upon closing (slamming) and cycling on the door and door hardware connections. This test method classifies the door performance as follows:

- EXTRA DUTY: 1 ,000,000 slam cycles,

- HEAVY DUTY: 500,000 slam cycles,

- STANDARD DUTY: 250,000 slam cycles.

[00165] In the following examples, the various lightweight concrete compositions were prepared to reach a paste volume of 49 vol. %. However, the paste volume is not limited to this particular value. For instance, in some embodiments, the paste volume of the lightweight concrete compositions (fiber-reinforced or air-entrained) can range from about 40 to about 60 vol. %.

[00166] In the following examples, the properties of the lightweight concrete compositions were determined after curing the concrete during 7 days at ambient temperature in between 80 and 100% R.H., and then drying during 7 days at 70°C.

EXAMPLE 1 : FIBER-REINFORCED LIGHTWEIGHT CONCRETE COMPOSITIONS

[00167] Several fiber-reinforced lightweight concrete compositions were prepared and tested for assessing their properties. Tables 19 to 21 summarize the experimental data for fiber-reinforced lightweight concrete compositions with or without talc as binder and including PVA as fibers. Tables 22 and 23 summarize the experimental data for fiber-reinforced lightweight concrete compositions with fly ash as binder and including PVA and/or polypropylene as fibers.

[00168] Tables 19, 22 and 23 provide the details of the tested compositions in term of the constituents and their content in the compositions. The results of the tests performed to evaluate the properties of the fiber-reinforced lightweight concrete compositions are reported in Tables 20 and 21.

[00169] The fiber-reinforced lightweight concrete compositions are designed using three formulation variables: (T)E/L, @ wt% talc or fly ash, and @ vol.% fibers, wherein E/L is a weight ratio between the water content and the binder content (i.e. the CAC, talc or fly ash content). [00170] Table 19: Tested fiber-reinforced lightweight concrete compositions with or without talc and including PVA fibers

O

o

[00171] Table 20: Properties of the fiber-reinforced lightweight concrete compositions with or without talc and including PVA fibers

n H o

[00172] Table 21 : Sawability of the fiber-reinforced lightweight concrete compositions

[00173] Table 22: Tested fiber-reinforced lightweight concrete compositions with fly ash

[00174] From the data presented in Table 20, one note that a decrease in E/L, a reduction in talc content and an increase in fiber volume lead to an increase in the screw holding capacity. From the data presented in Table 21 , one note that the concrete is more sawable, i.e. it shows a higher tenderness, for higher E/L or higher talc content. [00175] An additional fiber-reinforced lightweight concrete composition was prepared with the ingredients in the proportions reported in Table 23 below (Mix No. 14).

[00176] Table 23: fiber-reinforced lightweight concrete compositions with fly ash, PVA fibers and a viscosity agent - Mix No. 14

EXAMPLE 2: DOOR FRAMES MADE OF FIBER-REINFORCED LIGHTWEIGHT

CONCRETE COMPOSITIONS

[00177] Two door frames for fire doors as shown in Figs. 2 and 3, were manufactured using a fiber-reinforced lightweight concrete composition. The first door frame was manufactured using the lightweight concrete composition Mix No. 8 detailed in Table 19. In the lightweight concrete composition of the second door frame, the talc powder was replaced by class F fly ash to lower the manufacturing costs. The fiber-reinforced lightweight concrete composition Mix No. 15 having the composition detailed in Table 24 below was used in the second door frame. For Mix No. 15, the ratio E/L was 0.33, fly ashes were 15 wt% of binder (i.e. the mixture of cement, fly ash), 4 % of the concrete volume were PVA fibers, and the paste volume was 49 vol. %. Water represented about 26 wt% of the dry and solid matter.

[00178] Table 24: Composition of fiber-reinforced lightweight concrete composition Mix No. 15

[00179] The resulting properties of the fire door frame obtained using Mix No. 8 are shown in Table 25 below.

[00180] Table 25: Properties of the fire door frame made from Mix No. 8

[00181] Mix No. 8 is a good candidate for manufacturing a door frame since it provides a good compromise between its sawability and its pull-out resistance (above 3.1 kN). In fact, the door frame obtained using Mix No. 8 showed a relatively high pull-out resistance of about 3.7 kN thanks to the introduction of fibers in the concrete mixture. The pull-out resistance is desired for the hinge anchoring to the door frame.

[00182] Furthermore, Mix No. 8 showed a density of 1300 kg/m ³ due to its granular skeleton made of light particles, combined with a low cement content and the addition of synthetic fibers of low density. Despite this relatively low density, the concrete showed a compression of 21 MPa, which is sufficient to meet the mechanical properties requirements for fire door frame applications.

EXAMPLE 3: AIR-ENTRAINED LIGHTWEIGHT CONCRETE COMPOSITION

[00183] An air-entrained lightweight concrete was manufactured by mixing a first part A, in fresh state, with a second part B, where the first part A was a stable foam obtained by mixing a foaming agent with water and the second part B was a concrete composition, free of entrained air, obtained by conventional mixing. The second part B is equivalent to the above- described air-entrained lightweight concrete composition, without the air-entraining admixture. Through mixing parts A and B, one obtains the air-entrained lightweight concrete composition having the constituents as summarized in Table 26, below. In this example, Aerlite-iX™ from Aerix Industries was used as foaming agent.

[00184] Table 26: Constituents of the air-entrained lightweight concrete composition

EXAMPLE 4: FIRE DOOR ASSEMBLY INCLUDING AN AIR-ENTRAINED LIGHTWEIGHT CONCRETE COMPOSITION AND PROPERTIES THEREOF

[00185] A fire door core was manufactured using a mixture in accordance with the air- entrained lightweight concrete composition as detailed in Table 27 below.

[00186] Table 27: Air-entrained lightweight concrete composition for the fire door core

[00187] A fire door assembly was prepared with a core made of the air-entrained lightweight concrete composition of Table 27. The core portion and the doorframe were sawn to the desired size, planed, and bonded by a specialized company with tools used in the wood industry, to form the door body. Then, wood veneers were glued on both faces of the door body to complete the fire door assembly.

[00188] The properties of the air-entrained lightweight concrete obtained from the composition of Table 27 are summarized in Table 28 below. The fire resistance of the door cores was tested in accordance with UL 10(c) (2009), UBC 7-2 (1997) Part 1 , and ASTM E2074-04, Standard Method of Fire Tests of Door Assemblies (Positive Pressure), and CAN/ULC S104-10, UL 10(b) (2009), UBC 7-2 1994, and NFPA 252 (2008), Method of Fire Tests of Door Assemblies, under negative furnace pressure.

[00189] Table 28: Properties of the door core made of the air-entrained lightweight concrete composition of Table 27

[00190] In the fire resistance test, the door core remained intact and adhered to the door face and did not allow the passage of a stream of water through to the unexposed side. With the exception of the small section of stile, the door core met the conditions of acceptance of all standards throughout the hose stream test. EXAMPLE 5: FIRE DOOR PERFORMANCE TO CYCLE-SLAM TEST

[00191] A fire door was prepared with a core made of the air-entrained lightweight concrete composition of Table 27 and a door frame made of the fiber-reinforced lightweight concrete composition according to Mix No. 8 of Table 19. The core portion and the door frame were bonded to form the door body and then, wood veneers were glued on both faces of the door body.

[00192] The fire door was tested to assess its performance to repeated openings and closings using the Cycle-Slam Test. After 500,000 cycles (corresponding to a Heavy Duty category) the test was voluntarily stopped. The fire door was still functional. The frame showed a strong resistance to the repeated slams. Adhesion between the concrete door body and the veneer remained strong too.

[00193] Several alternative embodiments and examples have been described and illustrated herein. The embodiments described above are intended to be exemplary only. A person of ordinary skill in the art would appreciate the features of the individual embodiments, and the possible combinations and variations of the components. A person of ordinary skill in the art would further appreciate that any of the embodiments could be provided in any combination with the other embodiments disclosed herein. It is understood that the invention may be embodied in other specific forms without departing from the central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein. Accordingly, while the specific embodiments have been illustrated and described, numerous modifications come to mind. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.