WO2022015156A1

WO2022015156A1 - A non-metallic reinforcement bar and method of producing thereof

Info

Publication number: WO2022015156A1
Application number: PCT/MY2021/050060
Authority: WO
Inventors: Mei Si HUANG; Hon Wai CHEONG
Original assignee: Crt Manufacturing Sdn. Bhd.
Priority date: 2020-07-17
Filing date: 2021-07-15
Publication date: 2022-01-20

Abstract

The invention discloses a non-metallic reinforcement bar for reinforcing a mass of concrete material, the rebar comprising a glass fiber bundle bound together by a helical binding of textile material, and a coating of a curable adhesive composition comprising epoxy resin.

Description

ANON-METALLIC REINFORCEMENT BAR AND METHOD OF PRODUCING THEREOF

FIELD OF INVENTION

The present invention relates a construction technology for reinforcing a mass of concrete material, and more particularly to a non-metallic and light-weight reinforcement bar or rebar having enhanced structural integrity.

BACKGROUND OF THE INVENTION

Amass of concrete material is a rigid structure formed with microscopic opaque crystal lattices encapsulating fine and coarse aggregates. Typically, the structure is strong under compression but relatively weak in tensile strength, and any appreciable tension due to bending could break the lattices and results in cracking and breaking thereof.

Reinforcement bar or rebar selected from a rod, wire, mesh or cable can be embedded passively to strengthen the concrete material. Addition of rebar alters cracking mode of the concrete from macro-cracking to micro-cracking, and reduces crack width through stress redistribution. Conventionally, a carbon steel rebar is incorporated into the concrete material to provide great improvement in tensile strength, but the rebar is prone to oxidation and corrosion when exposes to moisture or salinity over a period of time. A corroded carbon steel rebar expands due to formation of rust layers and then causes further cracking in the concrete material, thereby accelerating structural failure.

Non-corrosive rebar made from glass bundle is provided to substitute the corrosive steel rebar, and a binder for enhancing structural integrity of the rebar. United States patent with publication no. US 20050095424A1 discloses an elongated structural rebar for reinforcing concrete material comprising woven glass reinforcing member that is wound into a roll such that a hydraulic binder being Portland cement can be embedded and dispersed therewithin to provide the reinforcement. Another United States patent with patent no. US4620401 discloses a structural rod for reinforcing a mass of concrete material which the rod is constituted of non-metallic continuous fibers bounded to each other by a thermosetting resin and polymerized in a geometrical profile which forms a mechanical anchorage with the mass which it is embedded.

Accordingly, it would be desirable to provide a reinforcement bar having smaller diameter yet higher durability as compared to the structural rod disclosed in US 20050095424 A1 andUS4620401, in which the reinforcement bar is formed from anon- metallic glass fiber bundle bound together by a textile material and coated with a curable adhesive composition. Particularly, the textile material is permeable to the composition that is first provided in a liquid form, which the composition solidifies therein upon curing to enhance structural integrity of the reinforcement bar.

SUMMARY OF INVENTION

An obj ect of the invention is to provide a non-metallic reinforcement bar for reinforcing a mass of concrete material, in which the reinforcement bar is provided with a glass fiber bundle bound together by a textile material, and a coating of curable adhesive composition coated thereon. The composition in its liquid form is permeable to voids within the fiber bundle and textile material and solidifies upon curing to enhance structural integrity of the reinforcement bar, such that the reinforcement bar exhibits higher tensile properties at a weight that is four times lower than a carbon steel reinforcement bar.

Another object of the invention is to provide a reinforcement bar for reinforcing a mass of concrete material, in which cutting of the reinforcement bar prevents or minimizes damage to a conventional cutting tool. Further another object of the invention is to provide non-metallic reinforcement bar for reinforcing a mass of concrete material, which the reinforcement bar is electromagnetically neutral and safe for use in constructing a designated space for an application involving external magnetic field, such as magnetic resonance imaging (MRI).

Still another object of the invention is to provide a method of producing a non-metallic reinforcement bar for reinforcing a mass of concrete material, in which the method dissipates low content of volatile compounds and hence less hazardous to the operator.

At least one of the preceding objects is met, in whole or in part, in which the embodiment of the present invention describes a non-metallic reinforcement bar for reinforcing a mass of concrete material, the rebar comprising a glass fiber bundle bound together by a helical binding of textile material, and a coating of a curable adhesive composition comprising epoxy resin.

Preferably, the curable adhesive composition further comprises a curing agent, a stabilizer, and a curing catalyst.

Preferably, the curable adhesive composition comprises 40 to 52% of the epoxy resin, 40 to 46% of the curing agent, 2 to 3% of the stabilizer, and 2 to 3% of the curing catalyst.

Preferably, the reinforcement bar includes particulate matter dispersed thereon and being of such composition and amount as to provide an outer rough surface.

Preferably, surface roughness of the reinforcement bar ranges from 8 to 25 Ra. Preferably, diameter of the reinforcement bar ranges from 0.3 to 40 mm. Another embodiment of the present invention discloses a method of producing a non- metallic reinforcement bar for reinforcing a mass of concrete material, the method comprises the steps of providing a glass fiber bundle bound together by a helical binding of textile material, and coating thereof with a curable adhesive composition comprising epoxy resin.

Preferably, the curable adhesive composition is cured at a temperature ranging from 200 to 400°C.

Preferably, the method further comprises dispersing particulate matter on the reinforcement bar and being of such composition and amount as to provide an outer rough surface.

One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiment described herein is not intended as limitations on the scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the invention shall be described according to the preferred embodiments of the present invention and by referring to the accompanying description and drawings. However, it is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications without departing from the scope of the appended claim.

As used herein, the term “reinforcement bar” and “rebar” may be used interchangeably.

The invention relates to a non-metallic reinforcement bar for reinforcing a mass of concrete material, which the reinforcement bar comprises a glass fiber bundle bound together by a helical binding of textile material, and a coating of a curable adhesive composition comprising epoxy resin. The rebar is primarily used for incorporating into the mass of concrete material to form a reinforcement concrete. The rebar is durable for use under extreme environment, such as high moisture and salinity, due to its non- corrosive nature.

The rebar is formed into a circular cross sectional area having a diameter ranging from 0.3 to 40 mm, which the diameter is adjustable based on amount of glass fiber bound therein. In one preferred embodiment, the fiber bundle can be extended along its longitudinal axis to form a straight rebar, or bent into a geometric shape to form a rebar having a shape akin thereto. The fiber bundle is bounded together by a helical binding of textile material, preferably a fibrous material and more preferably a cloth thread or yam. Preferably, the textile material is provided at a thickness ranging from 15 to 30 s. Optionally, a fiber roving having diameter of 5 to 15 pm can be used herein for such application.

The rebar further comprises the coating of curable adhesive composition comprising epoxy resin, and further comprising a curing agent, a stabilizer, and a curing catalyst to facilitate the curing of epoxy resin. Preferably, the curable adhesive composition comprises 40 to 52% of the epoxy resin, 40 to 46% of the curing agent, 2 to 3% of the stabilizer, and 2 to 3% of the curing catalyst. By way of example and not limitation, the epoxy resin is bisphenol A epoxy resin, the curing agent is isomethyltetrahydrophthalic anhydride, the stabilizer is glycidyl ether, and the curing catalyst is 2,4,6- Tris(dimethylaminomethyl)phenol alkofen.

The curable adhesive composition that is first provided in a liquid form, can be permeated through the textile material and voids within the glass fiber bundle, and solidified therein upon curing to enhance structural integrity of the rebar. As such, the rebar can withstand a stress of above 1000 MPa and exhibits low modulus of elasticity, in which the rebar deflects to its original shape as soon as the force exerted thereon is removed. The elastic properties ensures that post-production rebar cannot be bent or deformed permanently, thus providing additional safety to the reinforcement concrete therefrom.

Furthermore, the cured adhesive composition forms the coating on the rebar to protect the fiber bundle encapsulated therein from direct mechanical or chemical damage. The coating also provides lateral support for stress distribution between the fibers, which enables the rebar to exhibit a tensile strength ranging from 800 to 1250 MPa. Furthermore, the curable adhesive composition contributes to low thermal conductivity and fire retardant properties in the rebar, which these properties ensures durability of a building especially during a fire mishap, and reduces tendency of a structural failure.

In another preferred embodiment, the rebar further includes particulate matter dispersed thereon and being of such composition and amount as to provide an outer rough surface. The particulate matter having particle size lesser than 1 mm is preferred for dispersing on the rebar, such that to achieve a surface roughness ranging from 8 to 25 Ra. The rough surface enhances mechanical anchoring of the mass of concrete material, and improves overall mechanical properties of the reinforcement concrete. Furthermore, the rough surface also reduces tendency of slipping between the rebar and the mass of concrete material when the reinforced concrete is bearing a load. The invention is also characterized by a method of producing a non-metallic reinforcement bar for reinforcing a mass of concrete material, the method comprises the steps of providing a glass fiber bundle bound together by a helical binding of textile material, and coating thereof with a curable adhesive composition comprising epoxy resin. Particularly, the curable adhesive composition further comprises a curing agent, a stabilizer, and a curing catalyst. More particularly, the curable adhesive composition comprises 40 to 52% of the epoxy resin, 40 to 46% of the curing agent, 2 to 3% of the stabilizer, and 2 to 3% of the curing catalyst. By way of example and not limitation, the epoxy resin is bisphenol A epoxy resin, the curing agent is isomethyltetrahydrophthalic anhydride, the stabilizer is glycidyl ether, and the curing catalyst is 2,4,6- Tris(dimethylaminomethyl)phenol alkofen. The chemical selection for the curable adhesive composition dissipates lower content of volatile compounds, thus is less hazardous to the operator during its production.

In one preferred embodiment, the method involves pulling the glass fibers in a bundle through a reel stand towards a resin bath filled with the curable adhesive composition. The fiber bundle is formed into a circular cross sectional area having a diameter ranging from 0.3 to 40 mm, which the diameter depends on amount of glass fiber bundled therein. During the pulling of the glass fiber bundle, the textile material is spinning at a speed that enables formation of helical binding on the fiber bundle. The fiber bundle is then subjected to the resin bath and followed by curing at a temperature ranging from 200 to 400°C to form the coating thereon. Preferably, fiber bundle is cured for 2 to 8 minutes. The rebar is then cooled and reduced to a desired length for further application.

In another embodiment, the method further comprises dispersing particulate matter on the fiber bundle that has been subjected to the resin bath, prior to curing to obtain the coating thereon. Preferably, particle size of the particulate matter is lesser than 1 mm. The particulate matter provides an outer rough surface to the rebar to enhance mechanical anchoring of the mass of concrete material, improve overall mechanical properties of the reinforcement concrete, and reduce tendency of slipping between the rebar and the mass of concrete material especially during load bearing of the reinforced concrete. The present disclosure includes as contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a degree of particularly, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangements of parts may be resorted to without departing from the scope of the invention.

EXAMPLE

The following non-limiting example has been carried out to illustrate the preferred embodiments of the invention.

EXAMPLE 1

The curable adhesive composition comprises bisphenol A epoxy resin, isomethyltetrahydrophthalic anhydride, glycidyl ether and 2,4,6- Tris(dimethylaminomethyl)phenol (DMP-30) alkofen, and properties of each raw material is provided in Table 1 to 4.

Table 1: Properties of bisphenol A epoxy resin

Table 2: Properties of isomethyltetrahydrophthalic anhydride.

Table 3: Properties of glycidyl ether.

Table 4: Properties of 2,4,6-Tris(dimethylaminomethyl)phenol alkofen.

EXAMPLE 2

An alkali resistance test was carried out on the reinforcement bar of the present invention under ASTM D7705/D7705M - 12 for approximately 3 months. The reinforcement bar was subjected to an alkaline solution prepared by dissolving 118.5g calcium hydroxide, 0.9 g sodium hydroxide and 4.2 g of potassium hydroxide in 1 litre of tap water under a temperature of 60 ± 3°C. Results as shown in Table 5 and Table 6 suggest that the reinforcement bar is alkaline-resistance. Table 5: Observation on physical appearance and pH of alkaline solution.

Table 6: Mass change % in the reinforcement bar.

Claims

1. A non-metallic reinforcement bar for reinforcing a mass of concrete material, the rebar comprising a glass fiber bundle bound together by a helical binding of textile material, and a coating of a curable adhesive composition comprising epoxy resin.

2. The reinforcement bar according to claim 1, wherein the curable adhesive composition further comprises a curing agent, a stabilizer, and a curing catalyst.

3. The reinforcement bar according to claim 1 or 2, wherein the curable adhesive composition comprises 40 to 52% of the epoxy resin, 40 to 46% of the curing agent, 2 to 3% of the stabilizer, and 2 to 3% of the curing catalyst.

4. The reinforcement bar according to any one of the preceding claims, wherein the reinforcement bar includes particulate matter dispersed thereon and being of such composition and amount as to provide an outer rough surface.

5. The reinforcement bar according to claim 4, wherein surface roughness of the reinforcement bar ranges from 8 to 25 Ra.

6. The reinforcement bar according any one of claims 1 to 5, wherein diameter of the reinforcement bar ranges from 0.3 to 40 mm.

7. A method of producing a non-metallic reinforcement bar for reinforcing a mass of concrete material, the method comprises the steps of providing a glass fiber bundle bound together by a helical binding of textile material, and coating thereof with a curable adhesive composition comprising epoxy resin.

8. The method according to claim 7, wherein the curable adhesive composition further comprises a curing agent, a stabilizer, and a curing catalyst.

9. The method according to claim 7 or 8, wherein the curable adhesive composition comprises 40 to 52% of the epoxy resin, 40 to 46% of the curing agent, 2 to 3% of the stabilizer, and 2 to 3% of the curing catalyst.

10. The method according to any one of claims 7 to 9, wherein the curable adhesive composition is cured at a temperature ranging from 200 to 400°C.

11. The method according to any one of claims 7 to 10 further comprising dispersing particulate matter on the reinforcement bar and being of such composition and amount as to provide an outer rough surface.