Method for preparing high-strength and high-toughness concrete from regenerated glass fibers

Abstract

The invention provides a method for preparing high-strength and high-toughness concrete from regenerated glass fibers, and belongs to the field of building materials. The invention provides high-strength and high-toughness concrete, which is prepared from the following raw materials in parts by mass: 800 to 820 parts of cement; 100 to 150 parts of superfine slag powder; 60 to 105 parts of silica fume; 965 to 985 parts of river sand; 195 to 225 parts of water; 25 to 50 parts of coupling agent modified regenerated glass fiber; and 10-15 parts of a water reducing agent. On the basis, a method for calculating the 3d compressive strength of the high-strength and high-toughness concrete prepared from the regenerated glass fibers is provided. The superfine slag powder and the silica fume are used for replacing part of a cementing material, the cement consumption is remarkably reduced, and the later strength of the high-strength and high-toughness concrete is improved. The high-strength and high-toughness concrete prepared from the coupling agent modified regenerated glass fibers not only overcomes the defects that traditional concrete is easy to crack, high in brittleness, low in tensile strength and the like, but also can solve the accumulation problem of the regenerated glass fibers.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and in particular to a method for preparing high-strength and high-toughness concrete using recycled glass fibers. Background Art

[0002] Traditional concrete has the disadvantages of low tensile strength and poor durability, which makes it easy to crack during use, causing serious damage to the structure and seriously affecting the safety and service life of the engineering structure.

[0003] Glass fiber reinforced concrete (GFRC), a cement-based composite material composed of alkali-resistant glass fibers embedded in a cementitious material, offers excellent durability, chemical resistance, non-combustibility, tensile strength, and sound and thermal insulation. Consequently, GFRC is gaining increasing market favor. However, the recycling and crushing process damages the surface of the recycled glass fibers, reducing their mechanical strength. This results in lower strength and toughness in GFRC, and further improvements are needed.

[0004] In order to meet the requirements of modern engineering structural applications, recycled glass fiber concrete needs to have good strength and toughness. Currently, there are two main ways to improve the strength and toughness of glass fiber concrete: (1) Adjust the mix ratio and use fly ash to prepare recycled glass fiber concrete. After adding fly ash, the later strength of recycled glass fiber concrete is improved, but the early strength decreases. (2) Modify the surface of recycled glass fiber through heat treatment to improve the surface wettability of recycled glass fiber and the bonding performance between the recycled glass fiber surface and concrete, thereby improving the toughness of the concrete matrix. However, after heat treatment, the epoxy resin attached to the surface of recycled glass fiber is cracked, and the formed polymer is re-attached to the surface of recycled glass fiber. When the cement-based material is subjected to stress, the recycled glass fiber and the formed polymer are prone to debonding, forming a weak interface. At the same time, excessively high treatment temperature will damage the recycled glass fiber itself, reduce its mechanical strength, and thus reduce the bonding strength between it and the matrix.

[0005] Therefore, a glass fiber concrete with a new mix ratio and modification process is needed to ensure the strength and toughness of recycled glass fiber concrete. Summary of the Invention

[0006] The present invention provides a method for preparing high-strength and high-toughness concrete by using recycled glass fiber. The high-strength and high-toughness concrete of the present invention is not easy to crack and has the characteristics of high strength and high toughness.

[0007] The present invention provides a method for preparing high-strength and high-toughness concrete using recycled glass fiber, which comprises the following raw materials in parts by mass:

[0008]

[0009] Preferably, the average particle size of the slag powder is 40-45 μm, and the density is 2650-2800 kg / m 3 , with a specific surface area of ​​380 to 420 m 2 / g,

[0010] Calculated by mass fraction, the slag fine powder includes: CaO 37.56%, SiO2 35.01%, Al2O3 17.12%, MgO 5.44%, S 1.33%, Na2O 0.92%, TiO2 1.07%, K2O 0.93%, Fe2O3 0.32%, and MnO 0.3%.

[0011] Preferably, the total alkali content of the silica fume is ≤1.5wt%, the mass content of SiO2 is 91-94.5%, and the moisture content is ≤3.0wt%.

[0012] Preferably, the water content of the river sand is 2.4-3.0%, and the fineness modulus is 2.5-2.9.

[0013] Preferably, the cement comprises one or more Portland cements having a grade of 42.5 or above.

[0014] Preferably, the water reducer comprises a polycarboxylic acid-based high-efficiency water reducer; the water reduction rate of the water reducer is 18-28%.

[0015] Preferably, the coupling agent in the coupling agent-modified regenerated glass fiber is an aluminum-zirconium coupling agent.

[0016] Preferably, the metal content of the aluminum-zirconium coupling agent is 4.5-5%, the solid content is greater than 45%, and the density is 0.93-0.97 g / cm 3 .

[0017] The present invention also provides a method for calculating the 3D compressive strength of high-strength and high-toughness concrete prepared with recycled glass fiber as described in the above technical solution, which is characterized by comprising the following steps:

[0018] The raw materials for preparing high-strength and high-toughness concrete using recycled glass fibers according to the above technical solution are calculated respectively by calculating the water-binder ratio, mineral powder content ratio, silica fume content ratio, coupling agent modified recycled glass fiber content ratio and formula (1):

[0019] f cu =-35.929W+1.422M+38.121S+17.416G+41.562 Formula (1);

[0020] In formula (1): f cuThe 3d compressive strength of the high-strength and high-toughness concrete prepared with the recycled glass fiber; W is the water-binder ratio; M is the mineral powder content ratio; S is the silica fume content ratio; G is the coupling agent modified recycled glass fiber content ratio;

[0021] The mineral powder dosage ratio is the ratio of mineral powder to the total mass of mineral powder, silica fume and cement;

[0022] The silica fume content ratio is the ratio of silica fume to the total mass of slag, silica fume and cement;

[0023] The coupling agent modified recycled glass fiber dosage ratio is the ratio of the coupling agent modified recycled glass fiber to the total mass of the high-strength and high-toughness concrete.

[0024] The present invention also provides a method for preparing high-strength and high-toughness concrete using recycled glass fibers as described in the above technical solution, comprising the following steps:

[0025] Cement, slag powder, silica fume, river sand, coupling agent-modified recycled glass fiber, water and water reducer are mixed and then molded and cured in sequence to obtain the recycled glass fiber for preparing high-strength and high-toughness concrete.

[0026] In the present invention, slag powder and silica fume have gelling activity and can replace cementitious materials to prepare high-strength and high-toughness concrete, reducing the amount of cement used. At the same time, since the late gelling activity of silica fume is higher than that of cement, the late strength of high-strength and high-toughness concrete can be improved; the coupling agent-modified recycled glass fiber can effectively reduce the cracking of recycled glass fiber-reinforced high-strength and high-toughness concrete. The present invention incorporates the coupling agent-modified recycled glass fiber into concrete to prepare high-strength and high-toughness concrete, which can not only effectively overcome the shortcomings of traditional concrete such as easy cracking, high brittleness and low tensile strength, but also solve the problem of recycled glass fiber accumulation. The results of the examples of the present invention show that the 3d compressive strength of the high-strength and high-toughness concrete provided by the present invention is 31.53~39.53MPa, the 28d compressive strength is 64.13~71.15MPa; the 3d flexural strength is 6.15~7.67MPa, and the 28d flexural strength is 12.22~13.82MPa. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing high-strength and high-toughness concrete using recycled glass fiber, which comprises the following raw materials in parts by mass:

[0028]

[0029] In the present invention, unless otherwise specified, all raw materials are commercially available products well known to those skilled in the art.

[0030] The raw material for preparing high-strength, high-toughness concrete using the recycled glass fiber provided by the present invention includes 800-820 parts by weight of cement. In specific embodiments of the present invention, the cement content in the raw material can be 800, 805, 810, 815, or 820 parts by weight. The cement preferably includes one or more Portland cements with a grade of 42.5 or higher. The cement has a gelling effect.

[0031] Based on the unit mass fraction of the cement, the raw material for preparing high-strength and high-toughness concrete with the recycled glass fiber provided by the present invention includes 100 to 150 parts of slag powder; in a specific embodiment of the present invention, the mass fraction of slag powder in the raw material can be 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, 125 parts, 130 parts, 135 parts, 140 parts or 145 parts, the average particle size of the slag powder is preferably 40 to 45 μm, and the density is preferably 2650 to 2800 kg / m 3 The specific surface area is preferably 380 to 420 m 2 / g, in a specific embodiment of the present invention, the average particle size of the slag powder can be 40μm, 41μm, 42μm, 43μm, 44μm or 45μm, and the density can be 2650kg / m 3 , 2700kg / m 3 、2750kg / m 3 or 2800kg / m 3 , the specific surface area can be 380m 2 / g、390m 2 / g, 400m 2 / g、410m 2 / g or 420m 2 / g. Calculated by mass, the slag powder comprises: 37.56% CaO, 35.01% SiO2, 17.12% Al2O3, 5.44% MgO, 1.33% S, 0.92% Na2O, 1.07% TiO2, 0.93% K2O, 0.32% Fe2O3, and 0.3% MnO. The slag powder has the effect of improving the early strength of concrete.

[0032] The raw material for preparing high-strength and high-toughness concrete using recycled glass fiber provided by the present invention includes 60 to 105 parts by weight of silica fume, based on the unit weight of the cement. In specific embodiments of the present invention, the silica fume in the raw material may include 65, 70, 75, 85, 90, 95, or 100 parts by weight. The silica fume preferably has a total alkali content of ≤1.5%, a SiO2 content of 91 to 94.5%, and a moisture content of ≤3.0 wt%. The silica fume improves the later strength of concrete.

[0033] The raw material for preparing high-strength and high-toughness concrete using recycled glass fiber provided by the present invention includes 965 to 985 parts of river sand, based on the unit mass fraction of the cement. In specific embodiments of the present invention, the mass fraction of river sand in the raw material can be 965, 970, 975, 980, or 985 parts. The water content of the river sand is preferably 2.4 to 3.0%, and the fineness modulus is preferably 2.5 to 2.9. In specific embodiments of the present invention, the water content of the river sand can be 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9, or 3.0%, and the fineness modulus can be 2.5, 2.6, 2.7, 2.8, or 2.9. The river sand has the function of filling pores.

[0034] Based on the unit mass fraction of the cement, the raw materials for preparing high-strength and high-toughness concrete with the recycled glass fiber provided by the present invention include 195 to 225 parts of water; in a specific embodiment of the present invention, the mass fraction of water in the raw materials can be 195 parts, 200 parts, 205 parts, 210 parts, 215 parts, 220 parts or 225 parts; the water is preferably deionized water, and the water does not contain harmful impurities that affect the normal coagulation and hardening of cement, such as oils, sugars, and acids and alkalis.

[0035] Based on the unit mass fraction of the cement, the raw material for preparing high-strength and high-toughness concrete from the recycled glass fiber provided by the present invention includes 25 to 50 parts of coupling agent-modified recycled glass fiber; in a specific embodiment of the present invention, the mass fraction of the coupling agent-modified recycled glass fiber in the raw material can be 25 parts, 30 parts, 35 parts, 40 parts, 45 parts or 50 parts; in the present invention, the coupling agent-modified recycled glass fiber preferably includes an aluminum-zirconium coupling agent-modified recycled glass fiber; the metal content of the aluminum-zirconium coupling agent is preferably 4.5 to 5%, the solid content is preferably >45%, and the density is preferably 0.93 to 0.97 g / cm 3 The recycled glass fiber has the effect of improving the crack resistance of concrete.

[0036] Based on the unit mass fraction of the cement, the raw materials for preparing high-strength and high-toughness concrete with the recycled glass fiber provided by the present invention include 10 to 15 parts of a water reducer. In a specific embodiment of the present invention, the mass fraction of the water reducer can be 11 parts, 12 parts, 13 parts or 14 parts; the water reducer preferably includes one or more polycarboxylic acid-based high-efficiency water reducers; the water reduction rate of the water reducer is preferably 18 to 28%.

[0037] In the present invention, the method for preparing the coupling agent-modified regenerated glass fiber preferably comprises the following steps:

[0038] The regenerated glass fiber is washed and placed in a solution containing a coupling agent for modification, and the obtained wet-modified fiber is dried after solid-liquid separation.

[0039] In the present invention, the mass fraction of the coupling agent in the solution containing the coupling agent is preferably 10-20%. In a specific embodiment of the present invention, the mass fraction of the coupling agent in the solution containing the coupling agent can be 10%, 12%, 14%, 16%, 18% or 20%.

[0040] In the present invention, the modification temperature is preferably 20-40°C, and the modification time is preferably 4-12 hours. In the present invention, the modification temperature can be 20°C, 25°C, 30°C, 35°C or 40°C, and the modification time can be 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.

[0041] In the present invention, the drying temperature is preferably 110° C., and the drying time is preferably 5 minutes; and the drying is preferably carried out in an oven.

[0042] In terms of parts by mass, the raw materials for preparing high-strength and high-toughness concrete from the recycled glass fiber provided by the present invention include 10 to 15 parts of a water reducer; in a specific embodiment of the present invention, the mass fraction of the water reducer in the raw materials can be 11 parts, 12 parts, 13 parts, 14 parts or 15 parts; the water reducer preferably includes one or more polycarboxylic acid-based high-efficiency water reducers; the water reduction rate of the water reducer is preferably 18 to 28%. In the present invention, the water reduction rate of the water reducer can be 18%, 20%, 22%, 24%, 26% or 28%.

[0043] The present invention also provides a method for calculating the 3D compressive strength of high-strength and high-toughness concrete prepared by the recycled glass fiber, comprising the following steps:

[0044] According to the raw materials of the high-strength and high-toughness concrete described in the above technical solution, the water-binder ratio, mineral powder content ratio, silica fume content ratio, coupling agent modified recycled glass fiber content ratio and formula (1) are calculated respectively:

[0045] f cu =-35.929W+1.422M+38.121S+17.416G+41.562 Formula (1)

[0046] In formula (1): f cu is the 3d compressive strength of the high-strength and high-toughness concrete; W is the water-binder ratio; M is the mineral powder content ratio; S is the silica fume content ratio; G is the coupling agent modified recycled glass fiber content ratio;

[0047] The mineral powder dosage ratio is the ratio of mineral powder to the total mass of mineral powder, silica fume and cement;

[0048] The silica fume content ratio is the ratio of silica fume to the total mass of slag, silica fume and cement;

[0049] The coupling agent modified recycled glass fiber dosage ratio is the ratio of the coupling agent modified recycled glass fiber to the total mass of the high-strength and high-toughness concrete.

[0050] The present invention also provides a method for preparing high-strength and high-toughness concrete using the recycled glass fiber described in the above technical solution, comprising the following steps:

[0051] The high-strength and high-toughness concrete is obtained by mixing cement, slag powder, silica fume, river sand, coupling agent-modified recycled glass fiber, water and water reducing agent, and then molding and curing are carried out in sequence.

[0052] In the present invention, the mixing preferably includes:

[0053] Cement, slag powder, silica fume and water reducer are first mixed to obtain a first premix;

[0054] The first premix, river sand and part of water are mixed for a second time to obtain a second premix.

[0055] The second premix, coupling agent-modified recycled glass fiber and remaining water are mixed for the third time to obtain the high-strength and high-toughness concrete.

[0056] In the present invention, the mass ratio of the partial water to the remaining water is preferably 7.5-8.5:2.5-1.5, more preferably 8:2.

[0057] In the present invention, the first mixing, the second mixing and the third mixing are preferably independently performed by stirring, and the stirring time is preferably 1 to 2 minutes.

[0058] In the present invention, the step of injecting the mixed slurry into a mold before molding is preferably included.

[0059] In the present invention, the molding is preferably carried out under vibration conditions. In the present invention, the vibration frequency is preferably 80 to 120 Hz, and the duration is preferably 50 to 70 seconds. In a specific embodiment of the present invention, the vibration frequency may be 80 Hz, 90 Hz, 100 Hz, 105 Hz, 110 Hz, 115 Hz, or 120 Hz, and the duration may be 50 seconds, 60 seconds, 65 seconds, or 70 seconds, more preferably 95 to 105 Hz.

[0060] In the present invention, the curing preferably includes pre-demolding curing and post-demolding curing: the temperature of the pre-demolding curing is preferably room temperature, and the time is preferably 24 to 48 hours; the method of curing before demolding is preferably to cover the surface of the vibrated blank with a layer of plastic film for curing; the curing method of the post-demolding curing is preferably water curing.

[0061] The method for preparing high-strength and high-toughness concrete using recycled glass fibers provided by the present invention is described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0062] Cement: 42.5 Portland cement;

[0063] Slag powder: average particle size is 40μm, density is 2750kg / m 3 , with a specific surface area of ​​400m 2 / g, and in terms of mass fraction, the components of the slag fine powder are: CaO 37.56%, SiO2 35.01%, Al2O3 17.12%, MgO 5.44%, S1.33%, Na2O 0.92%, TiO2 1.07%, K2O 0.93%, Fe2O3 0.32%, and MnO 0.3%.

[0064] Silica fume: total alkali content is 0.4wt%, mass content of SiO2 is 94.5%, and moisture content is 0.5wt%.

[0065] The moisture content of river sand is 2.7%; the fineness modulus is 2.65.

[0066] Water reducer: polycarboxylic acid-based high-efficiency water reducer with a water reduction rate of 28%, purchased from Shanxi Feike New Material Technology Co., Ltd.

[0067] The preparation method of coupling agent modified regenerated glass fiber is as follows:

[0068] 10 g of recycled glass fiber with an average length of 12 mm was washed and placed in 200 mL of a solution containing an aluminum-zirconium coupling agent (the mass fraction of the aluminum-zirconium coupling agent (TL-2 type aluminum-zirconium coupling agent produced by Chongqing Gaoyao Technology Co., Ltd.) was 15%) for modification (temperature of 25°C for 12 h). After the modification was completed, the recycled glass fiber was heated at 110°C for 5 min, and the modified recycled glass fiber was obtained after complete drying.

[0069] Examples 1 to 3

[0070] Table 1: Proportions of recycled glass fiber reinforced high strength and high toughness concrete components in Examples 1 to 3 (kg / m 3 )

[0071]

[0072] Note: The dosage in Examples 1 to 3 of the present invention is based on a total volume of 1m 3 Make the proportions.

[0073] The preparation method is as follows: according to the proportions described in Table 1, cement, slag powder, silica fume, and water reducer are weighed and mixed at room temperature for 1 minute to obtain a first premix;

[0074] The first premix, river sand and 169.12kg / m 3 Deionized water is mixed for a second time at room temperature for 2 minutes to obtain a second premix;

[0075] The second premix, recycled glass fiber and the remaining 42.28 kg / m 3 Deionized water is mixed for a third time at room temperature for 2 minutes to obtain a third premix; the third premix is ​​vibrated for 60 seconds at a vibration frequency of 100 Hz to obtain a recycled glass fiber reinforced high-strength and high-toughness concrete body; a layer of plastic film is covered on the surface of the recycled glass fiber reinforced high-strength and high-toughness concrete body and cured at room temperature for 24 hours, and then standard curing is carried out at a humidity of 95% and a temperature of 20±2°C.

[0076] Test Case

[0077] According to the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" GB / T50081-2019 and the "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete" GB / T50082-2009, the 3d compressive strength, 3d flexural strength, 28d compressive strength, and 28d flexural strength of the recycled glass fiber reinforced high-strength and high-toughness concrete prepared in Examples 1 to 3 were tested, and the results are shown in Table 2.

[0078] Table 2 Performance test results of recycled glass fiber reinforced high strength and high toughness concrete described in Examples 1 to 3

[0079]

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing high-strength and high-toughness concrete using recycled glass fiber, characterized in that: Calculated by mass, it includes the following raw materials:

2. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 1, wherein: The average particle size of the slag powder is 40-45 μm, and the density is 2650-2800 kg / m 3 , with a specific surface area of ​​380 to 420 m 2 / g, Calculated by mass fraction, the slag fine powder includes: CaO 37.56%, SiO2 35.01%, Al2O3 17.12%, MgO 5.44%, S 1.33%, Na2O 0.92%, TiO2 1.07%, K2O 0.93%, Fe2O3 0.32%, and MnO 0.3%.

3. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 1, wherein: The total alkali content of the silica fume is ≤1.5wt%, the mass content of SiO2 is 91-94.5%, and the moisture content is ≤3.0wt%.

4. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 1, wherein: The water content of the river sand is 2.4-3.0%, and the fineness modulus is 2.5-2.

9.

5. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 1, wherein: The cement includes one or more Portland cements with a grade of 42.5 or above.

6. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 1, wherein: The water reducer comprises a polycarboxylic acid-based high-efficiency water reducer; the water reduction rate of the water reducer is 18-28%.

7. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 1, wherein: The coupling agent in the coupling agent-modified regenerated glass fiber is an aluminum-zirconium coupling agent.

8. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to claim 7, wherein: The aluminum-zirconium coupling agent has a metal content of 4.5-5%, a solid content of >45%, and a density of 0.93-0.97 g / cm 3 .

9. The method for calculating the 3d compressive strength of high-strength and high-toughness concrete prepared with recycled glass fiber according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials for preparing high-strength and high-toughness concrete using recycled glass fiber according to any one of claims 1 to 8 are calculated by respectively calculating the water-binder ratio, the mineral powder content ratio, the silica fume content ratio, and the coupling agent-modified recycled glass fiber content ratio and formula (1): f cu =-35.929W+1.422M+38.121S+17.416G+41.562 Formula (1); In formula (1): f cu The 3d compressive strength of the high-strength and high-toughness concrete prepared with the recycled glass fiber; W is the water-binder ratio; M is the mineral powder content ratio; S is the silica fume content ratio; G is the coupling agent modified recycled glass fiber content ratio; The mineral powder dosage ratio is the ratio of mineral powder to the total mass of mineral powder, silica fume and cement; The silica fume content ratio is the ratio of silica fume to the total mass of slag, silica fume and cement; The coupling agent modified recycled glass fiber content ratio is the ratio of the coupling agent modified recycled glass fiber to the total mass of the high-strength and high-toughness concrete.

10. The method for preparing high-strength and high-toughness concrete using recycled glass fiber according to any one of claims 1 to 8, characterized in that: The following steps are involved: Cement, slag powder, silica fume, river sand, coupling agent-modified recycled glass fiber, water and water reducer are mixed and then molded and cured in sequence to obtain the recycled glass fiber for preparing high-strength and high-toughness concrete.

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