Alkali-resistant glass fiber composite reinforcing bar for concrete and preparation method thereof

Abstract

The present application relates to the technical field of fiber reinforced composite materials, and particularly relates to an alkali-resistant glass fiber composite bar for concrete and a preparation method thereof. The alkali-resistant glass fiber composite bar for concrete is obtained by impregnating a composite alkali-resistant glass fiber bundle in adhesive resin and then performing pultrusion molding; the composite alkali-resistant glass fiber bundle is obtained by bundling alkali-resistant glass fibers into an alkali-resistant glass fiber bundle with a diameter of 2±0.3 mm, impregnating the alkali-resistant glass fiber bundle in reactive resin slurry, pulling, drying and curing, and then collecting. The alkali-resistant glass fiber composite bar for concrete prepared by the present application has excellent mechanical properties, high-temperature resistance and alkali resistance, and can partially replace steel bars to be used in the preparation of concrete and be widely applied in marine engineering.

Description

Technical Field

[0001] This invention relates to the field of fiber-reinforced composite materials technology, and in particular to an alkali-resistant glass fiber composite bar for concrete and its preparation method. Background Technology

[0002] Fiber-reinforced composite materials are widely used in marine engineering and other fields due to their advantages such as lightweight, high strength, and corrosion resistance. However, the alkali resistance of glass fiber reinforced composite bars limits their long-term application in concrete structures, especially their durability in alkaline environments.

[0003] The strength and performance of the fiber are highly dependent on the bond strength between the fiber and the resin. In an alkaline environment, the penetration of hydroxide ions leads to a decrease in the bond strength at the fiber-resin interface, resulting in debonding, which directly affects the mechanical properties of the composite material. Furthermore, alkali-resistant glass fibers may undergo hydrolysis and dissociation in strong alkaline solutions, leading to damage to their molecular structure and a decrease in strength. Long-term immersion can cause microscopic defects and cracks in the fibers, further reducing the material's load-bearing capacity. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide an alkali-resistant glass fiber composite bar for concrete and its preparation method, so as to improve the alkali resistance and reinforcing effect of the glass fiber composite bar in concrete.

[0005] To achieve the above objectives, the present invention provides an alkali-resistant glass fiber composite rebar for concrete, which is obtained by impregnating composite alkali-resistant glass fiber bundles in bonding resin and then pultruding it.

[0006] Preferably, the diameter of the alkali-resistant glass fiber composite reinforcement for concrete is 6mm-40mm;

[0007] More preferably, the diameter of the alkali-resistant glass fiber composite reinforcement for concrete is 10±0.5mm.

[0008] Preferably, the weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 60%-65%.

[0009] Preferably, the adhesive resin is a mixture of vinyl resin and curing agent in a weight ratio of 100:1.

[0010] Furthermore, the composite alkali-resistant glass fiber bundle is made by grafting sodium montmorillonite onto alkali-resistant glass fiber, bundling it into an alkali-resistant glass fiber bundle with a diameter of 2±0.3mm, impregnating it in a reactive resin slurry, drawing it, drying and curing it, and collecting it to obtain the composite alkali-resistant glass fiber bundle.

[0011] Preferably, the weight content of the alkali-resistant glass fiber bundle in the composite alkali-resistant glass fiber bundle is 98% ± 0.5%.

[0012] Furthermore, the preparation method of the reactive resin slurry is as follows:

[0013] (1) Polyethylene glycol with a molecular weight of 2000 and isoflurane diisocyanate were added to butanone, stirred and dissolved, heated to 45-50℃, reacted for 1-2 hours, and then heated to 75-85℃. N-hydroxymethylacrylamide, 2-hydroxypropyltrimethylammonium chloride and epoxy resin E51 were added, reacted for 5-6 hours, and rotary evaporated to obtain the reactive resin.

[0014] (2) Add the reactive resin and sodium montmorillonite to deionized water, heat to 60-70℃, stir and disperse to obtain reactive resin slurry.

[0015] Preferably, the vinyl resin is an epoxy vinyl resin.

[0016] Preferably, the traction speed is 0.2-0.3 m / min.

[0017] Preferably, the drying and curing temperature is 150-160℃ and the time is 5-6 hours.

[0018] Preferably, in step (1), the weight ratio of polyethylene glycol, isoflurane diisocyanate, methyl ethyl ketone, N-(hydroxymethyl)acrylamide, 2-hydroxypropyltrimethylammonium chloride and epoxy resin E51 is 10:2.2:25:0.25:0.38:9.

[0019] Preferably, in step (2), the weight ratio of reactive resin, sodium montmorillonite and deionized water is 1:0.1-0.5:100.

[0020] Furthermore, the present invention also provides a method for preparing alkali-resistant glass fiber composite reinforcement for concrete, comprising the following steps:

[0021] (1) Mix vinyl resin and curing agent to obtain adhesive resin;

[0022] (2) The composite alkali-resistant glass fiber bundle is impregnated in bonding resin, and then pultruded, wound, cured at high temperature and cut to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 10±0.5mm.

[0023] The beneficial effects of this invention are:

[0024] This invention uses alkali-resistant glass fiber to prepare composite reinforcement. The alkali-resistant glass fiber contains zirconium dioxide, which can significantly produce a zirconium-rich phenomenon under the erosion of the alkaline environment of concrete, forming a dense protective film, slowing down the erosion rate of hydroxide ions on silicon dioxide, and significantly improving alkali resistance.

[0025] The alkali-resistant glass fiber composite reinforcement for concrete prepared by this invention uses ammonium salt, alkenyl group and epoxy group to construct a reactive resin, which can adhere to the surface of alkali-resistant glass fiber through ionic bond and coordination bond. The ammonium salt helps to improve alkali resistance and exchange ions with the internal nano-montmorillonite, and the alkenyl group helps to further react with the outer vinyl resin, thereby building a "bridge" between the vinyl resin and alkali-resistant glass fiber, improving adhesion and giving full play to the reinforcing effect of alkali-resistant glass fiber.

[0026] The present invention further adds sodium montmorillonite to the reactive resin slurry. The sodium montmorillonite is uniformly dispersed in the reactive resin through ion exchange, which improves the alkali resistance and tensile strength of the alkali-resistant glass fiber composite bar.

[0027] The alkali-resistant glass fiber composite reinforcement for concrete provided by this invention has high mechanical properties, high temperature resistance and alkali resistance, and can partially replace steel bars in the preparation of concrete, and is widely used in marine engineering. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0029] In this specific embodiment of the invention, the epoxy vinyl resin is Liliansi 430ACT; the curing agent is Shuojin. MEKP-925H, sodium montmorillonite, was purchased from NANOCOR, model PGW.

[0030] The main physical parameters of the alkali-resistant glass fiber in the specific embodiments of the present invention are shown in Table 1.

[0031] Table 1 Main physical parameters of alkali-resistant glass fiber

[0032] Single filament diameter / μm Elastic modulus / GPa Tensile strength / MPa Zirconium content / % Loss on ignition / % 14 75 1650 16.7 2.2

[0033] Example 1:

[0034] (1) Add 10g of polyethylene glycol with a molecular weight of 2000 and 2.2g of isoflurane diisocyanate to 25g of butanone, stir to dissolve, heat to 45℃, react for 2h, continue to heat to 75℃, add 0.25g of N-hydroxymethylacrylamide, 0.38g of 2-hydroxypropyltrimethylammonium chloride and 9g of epoxy resin E51, react for 6h, rotary evaporate to obtain reactive resin;

[0035] (2) Add 10g of reactive resin and 1g of sodium montmorillonite to 500g of deionized water, heat to 60℃, stir and disperse to obtain reactive resin slurry.

[0036] (3) The alkali-resistant glass fibers are bundled into alkali-resistant glass fiber bundles with a diameter of 1.8 mm, then impregnated in reactive resin slurry, pulled at 0.2 m / min, dried and cured at 150°C for 6 h, and collected to obtain composite alkali-resistant glass fiber bundles. The weight content of alkali-resistant glass fiber bundles in the composite alkali-resistant glass fiber bundles is 97.8%.

[0037] (4) Mix epoxy vinyl resin and curing agent at a weight ratio of 100:1 to obtain adhesive resin;

[0038] (5) The composite alkali-resistant glass fiber bundles are impregnated in bonding resin and pultruded to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 10.3 mm. The weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 64.5%.

[0039] Example 2:

[0040] (1) Add 10g of polyethylene glycol with a molecular weight of 2000 and 2.2g of isoflurane diisocyanate to 25g of butanone, stir to dissolve, heat to 50℃, react for 2h, continue to heat to 80℃, add 0.25g of N-hydroxymethylacrylamide, 0.38g of 2-hydroxypropyltrimethylammonium chloride and 9g of epoxy resin E51, react for 5h, rotary evaporate to obtain reactive resin;

[0041] (2) Add 10g of reactive resin and 3g of sodium montmorillonite to 800g of deionized water, heat to 65℃, stir and disperse to obtain reactive resin slurry.

[0042] (3) The alkali-resistant glass fibers are bundled into alkali-resistant glass fiber bundles with a diameter of 2.1 mm, then impregnated in reactive resin slurry, pulled at 0.2 m / min, dried and cured at 160℃ for 5 h, and collected to obtain composite alkali-resistant glass fiber bundles. The weight content of alkali-resistant glass fiber bundles in the composite alkali-resistant glass fiber bundles is 98.2%.

[0043] (4) Mix the vinyl resin and the curing agent at a weight ratio of 100:1 to obtain the bonding resin;

[0044] (5) The composite alkali-resistant glass fiber bundles are impregnated in bonding resin and pultruded to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 9.9 mm. The weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 63.2%.

[0045] Example 3:

[0046] (1) Add 10g of polyethylene glycol with a molecular weight of 2000 and 2.2g of isoflurane diisocyanate to 25g of butanone, stir to dissolve, heat to 50℃, react for 1h, continue to heat to 85℃, add 0.25g of N-hydroxymethylacrylamide, 0.38g of 2-hydroxypropyltrimethylammonium chloride and 9g of epoxy resin E51, react for 5h, rotary evaporate to obtain reactive resin;

[0047] (2) Add 10g of reactive resin and 5g of sodium montmorillonite to 1000g of deionized water, heat to 70℃, stir and disperse to obtain reactive resin slurry.

[0048] (3) The alkali-resistant glass fibers are bundled into alkali-resistant glass fiber bundles with a diameter of 2.2 mm, then impregnated in reactive resin slurry, pulled at 0.3 m / min, dried and cured at 160℃ for 5 h, and collected to obtain composite alkali-resistant glass fiber bundles. The weight content of alkali-resistant glass fiber bundles in the composite alkali-resistant glass fiber bundles is 98.3%.

[0049] (4) Mix the vinyl resin and the curing agent at a weight ratio of 100:1 to obtain the bonding resin;

[0050] (5) The composite alkali-resistant glass fiber bundles are impregnated in bonding resin and pultruded to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 9.6 mm. The weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 60.5%.

[0051] Comparative Example 1:

[0052] The main difference between Comparative Example 1 and Example 2 is that no reactive resin was added;

[0053] (1) Bundle the alkali-resistant glass fibers into alkali-resistant glass fiber bundles with a diameter of 2 mm.

[0054] (2) Mix the vinyl resin and the curing agent at a weight ratio of 100:1 to obtain the bonding resin;

[0055] (3) The alkali-resistant glass fiber bundles were impregnated in the bonding resin and pultruded to obtain an alkali-resistant glass fiber composite bar with a diameter of 10 mm. The weight content of the alkali-resistant glass fiber bundles in the glass fiber composite bar was 64.4%.

[0056] Comparative Example 2:

[0057] The main difference between Comparative Example 2 and Example 2 is that N-hydroxymethylacrylamide was not added to the reactive resin;

[0058] (1) Add 10g of polyethylene glycol with a molecular weight of 2000 and 2.2g of isoflurane diisocyanate to 25g of butanone, stir to dissolve, heat to 50℃, react for 2h, continue to heat to 80℃, add 0.38g of 2-hydroxypropyltrimethylammonium chloride and 9g of epoxy resin E51, react for 5h, rotary evaporate to obtain reactive resin;

[0059] (2) Add 10g of reactive resin and 3g of sodium montmorillonite to 800g of deionized water, heat to 65℃, stir and disperse to obtain reactive resin slurry.

[0060] (3) The alkali-resistant glass fibers are bundled into alkali-resistant glass fiber bundles with a diameter of 2.1 mm, then impregnated in reactive resin slurry, pulled at 0.2 m / min, dried and cured at 160℃ for 5 h, and collected to obtain composite alkali-resistant glass fiber bundles. The weight content of alkali-resistant glass fiber bundles in the composite alkali-resistant glass fiber bundles is 98.2%.

[0061] (4) Mix the vinyl resin and the curing agent at a weight ratio of 100:1 to obtain the bonding resin;

[0062] (5) The composite alkali-resistant glass fiber bundles are impregnated in bonding resin and pultruded to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 9.9 mm. The weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 63.1%.

[0063] Comparative Example 3:

[0064] The main difference between Comparative Example 3 and Example 2 is that 2-hydroxypropyltrimethylammonium chloride was not added to the reactive resin;

[0065] (1) Add 10g of polyethylene glycol with a molecular weight of 2000 and 2.2g of isoflurane diisocyanate to 25g of butanone, stir to dissolve, heat to 50℃, react for 2h, continue to heat to 80℃, add 0.25g of N-hydroxymethylacrylamide and 9g of epoxy resin E51, react for 5h, rotary evaporate to obtain reactive resin;

[0066] (2) Add 10g of reactive resin and 3g of sodium montmorillonite to 800g of deionized water, heat to 65℃, stir and disperse to obtain reactive resin slurry.

[0067] (3) The alkali-resistant glass fibers are bundled into alkali-resistant glass fiber bundles with a diameter of 2.1 mm, then impregnated in reactive resin slurry, pulled at 0.2 m / min, dried and cured at 160℃ for 5 h, and collected to obtain composite alkali-resistant glass fiber bundles. The weight content of alkali-resistant glass fiber bundles in the composite alkali-resistant glass fiber bundles is 98.2%.

[0068] (4) Mix the vinyl resin and the curing agent at a weight ratio of 100:1 to obtain the bonding resin;

[0069] (5) The composite alkali-resistant glass fiber bundles are impregnated in bonding resin and pultruded to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 9.9 mm. The weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 63.3%.

[0070] Comparative Example 4:

[0071] The main difference between Comparative Example 4 and Example 2 is that sodium montmorillonite was not added to the reactive resin slurry;

[0072] (1) Add 10g of polyethylene glycol with a molecular weight of 2000 and 2.2g of isoflurane diisocyanate to 25g of butanone, stir to dissolve, heat to 50℃, react for 2h, continue to heat to 80℃, add 0.25g of N-hydroxymethylacrylamide, 0.38g of 2-hydroxypropyltrimethylammonium chloride and 9g of epoxy resin E51, react for 5h, rotary evaporate to obtain reactive resin;

[0073] (2) Add 13g of reactive resin to 800g of deionized water, heat to 65℃, stir and disperse to obtain reactive resin slurry;

[0074] (3) The alkali-resistant glass fibers are bundled into alkali-resistant glass fiber bundles with a diameter of 2.1 mm, then impregnated in reactive resin slurry, pulled at 0.2 m / min, dried and cured at 160℃ for 5 h, and collected to obtain composite alkali-resistant glass fiber bundles. The weight content of alkali-resistant glass fiber bundles in the composite alkali-resistant glass fiber bundles is 98.1%.

[0075] (4) Mix the vinyl resin and the curing agent at a weight ratio of 100:1 to obtain the bonding resin;

[0076] (5) The composite alkali-resistant glass fiber bundles are impregnated in bonding resin and pultruded to obtain alkali-resistant glass fiber composite reinforcement for concrete with a diameter of 9.9 mm. The weight content of the composite alkali-resistant glass fiber bundles in the alkali-resistant glass fiber composite reinforcement for concrete is 63.4%.

[0077] Performance testing:

[0078] Tensile strength: The tensile mechanical properties were tested on a universal testing machine in accordance with GB / T 30022-2013 "Test Method for Basic Mechanical Properties of Fiber Reinforced Composite Reinforcement". The samples were then placed at 100℃ for 24 hours and the tensile mechanical properties were tested again. The results are shown in Table 2.

[0079] Alkali resistance test: 15g of sodium hydroxide was dissolved in 1000ml of deionized water to obtain an alkaline solution, which was then placed in a constant temperature water tank and kept at 60℃. The alkali-resistant glass fiber composite bars prepared in the examples and comparative examples with both ends protected were then immersed in the alkaline solution for 15d, 30d, 60d and 90d respectively. The samples after the immersion time expired were taken out and subjected to tensile strength test. The tensile strength retention rate relative to the blank sample was calculated. The results are shown in Table 2.

[0080] Table 2 Performance Test Results

[0081]

[0082] Data Analysis:

[0083] As can be seen from the data of Examples 1-3 in Table 2, the alkali-resistant glass fiber composite reinforcement for concrete prepared by the present invention has high tensile strength, indicating that it has strong mechanical properties, especially at high temperatures, it can still maintain high mechanical properties. Most importantly, after undergoing an alkali resistance test at 60°C for 90 days, it can still maintain more than 85% of its tensile strength, indicating that it has strong alkali resistance.

[0084] As can be seen from the data in Table 2 of Example 2 and Comparative Examples 1-3, reactive resin helps to improve tensile strength. This is mainly because the reactive resin adheres to the surface of alkali-resistant glass fiber through ionic and coordination bonds, and can react with the outer vinyl ester resin to build a bridge between the vinyl ester resin and the alkali-resistant glass fiber, thereby improving compatibility.

[0085] As can be seen from the data in Example 2 and Comparative Example 4 in Table 2, montmorillonite in reactive resin slurry can improve tensile strength. Most importantly, it has a significant effect on alkali resistance. This is mainly due to the excellent dispersibility of montmorillonite in reactive resin. Montmorillonite and ammonium salts in reactive resin can undergo ion exchange, which allows alkali-resistant glass fiber composite reinforcement for concrete to still have high tensile strength at high temperatures. Moreover, the flake-like montmorillonite can further block the erosion of alkali-resistant glass fibers by alkaline solutions, thereby improving alkali resistance.

[0086] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples. Within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. An alkali-resistant glass fiber composite bar for concrete, characterized by, The alkali-resistant glass fiber composite reinforcing bar for concrete is prepared by impregnating the alkali-resistant glass fiber bundle in the bonding resin and then performing pultrusion molding; the weight content of the alkali-resistant glass fiber bundle in the alkali-resistant glass fiber composite reinforcing bar for concrete is 60%-65%; the bonding resin is a mixture of the vinyl resin and the curing agent in a weight ratio of 100:1; The alkali-resistant glass fiber bundle is prepared by bundling the alkali-resistant glass fibers into an alkali-resistant glass fiber bundle with a diameter of 2±0.3 mm, then impregnating the alkali-resistant glass fiber bundle in the reactive resin slurry, performing traction, drying and curing, and collecting; the weight content of the alkali-resistant glass fiber bundle in the alkali-resistant glass fiber bundle is 98%±0.5%; The preparation method of the reactive resin slurry is as follows: (1) polyethylene glycol with a molecular weight of 2000 and isophorone diisocyanate are added into butanone, stirred and dissolved, heated to 45-50℃, reacted for 1-2h, continuously heated to 75-85℃, N-hydroxymethyl acrylamide, 2-hydroxypropyl trimethyl ammonium chloride and epoxy resin E51 are added, reacted for 5-6h, and rotary evaporated to obtain the reactive resin; (2) the reactive resin and sodium-based montmorillonite are added into deionized water, heated to 60-70℃, stirred and dispersed to obtain the reactive resin slurry; In step (1), the weight ratio of polyethylene glycol, isophorone diisocyanate, butanone, N-hydroxymethyl acrylamide, 2-hydroxypropyl trimethyl ammonium chloride and epoxy resin E51 is 10:2.2:25:0.25:0.38:9; In step (2), the weight ratio of the reactive resin, sodium-based montmorillonite and deionized water is 1:0.1-0.5:

100.

2. The alkali-resistant glass fiber composite reinforcing bar for concrete according to claim 1, characterized in that, The vinyl resin is an epoxy vinyl resin.

3. The alkali-resistant glass fiber composite reinforcing bar for concrete according to claim 1, characterized in that, The speed of traction is 0.2-0.3m / min.

4. The alkali-resistant glass fiber composite reinforcing bar for concrete according to claim 1, characterized in that, The temperature of drying and curing is 150-160℃, and the time is 5-6h.

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