Fiber reinforced high performance polymer concrete, method of making and use thereof

Abstract

The application provides a kind of fiber reinforced high performance geopolymer concrete and its preparation method and application, and the concrete includes the following raw materials: fly ash, slag, quartz powder, alkali activator, barium chloride, water and modified fiber;The content of modified fiber is 1% to 2%;The fiber material is placed in ethanol for ultrasonic treatment;Add the first silane coupling agent to the system after ultrasonic treatment and adjust the pH of the system to 5.5 to 6.5;Add the second silane coupling agent to the system after adjusting the pH, stir and react at 40 to 50 DEG C for 2 to 3 hours, then add bisphenol A type epoxy resin, continue to stir for 1 to 2 hours, and prepare modified fiber;The fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber, and the volume ratio of polyethylene fiber to polyvinyl alcohol fiber is (1 to 3) to 1, which solves the problem of poor toughness and easy cracking of geopolymer concrete in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete materials, in particular to a fiber-reinforced high-performance geopolymer concrete and a preparation method and application thereof. BACKGROUND

[0002] Concrete is the most widely used building material at present, and high-performance concrete represents the development direction of concrete technology. In recent years, with the vigorous development of the domestic construction industry, the strength and anti-cracking performance of the concrete consumed during construction are continuously improved. However, the inherent weakness of concrete is that as the strength is continuously improved, the toughness is deteriorated, the brittleness is improved, and cracks are easily generated. The appearance and expansion of cracks will cause performance degradation and thus shorten the service life.

[0003] The term "geopolymer" was first proposed by a French materials scientist Davidovits in 1976 as a new type of alkali-activated inorganic cementitious material. Geopolymer is an inorganic high-molecular polymer with a three-dimensional network structure composed of silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron, which is formed by alkali-activated solid powder rich in silicon and aluminum. Studies have shown that compared with Portland cement, geopolymer has the advantages of high strength, acid resistance, large surface hardness, fire resistance, good thermal stability, and ability to solidify heavy metals. However, geopolymer concrete is a brittle material with a large self-weight and is prone to generate a large number of cracks, which does not meet the sustainable and high-performance requirements of new materials for use, and limits its application in building engineering materials. Therefore, developing geopolymer high-performance concrete with high strength and high ductility at the same time is of great significance for the development direction of future concrete technology. SUMMARY

[0004] The main purpose of the present application is to provide a fiber-reinforced high-performance geopolymer concrete and a preparation method and application thereof, so as to solve the problem of poor toughness and easy cracking of the geopolymer concrete in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a fiber-reinforced high-performance geopolymer concrete is provided, which comprises the following raw materials: fly ash, slag, quartz powder, alkali activator, barium chloride, water and modified fiber.

[0006] The mass ratio of fly ash, slag, quartz powder, alkali activator, barium chloride and water is 620.3-849.7:364.1-620.3:242.8-248.1:485.5-496.2:72.8-74.3:12.1-12.4;

[0007] The content of the modified fiber is 1%-2% based on the volume percentage of the fiber-reinforced high-performance geopolymer concrete;

[0008] The modified fiber is prepared by the following steps:

[0009] Step S01, the fiber material is placed in an ethanol aqueous solution for ultrasonic treatment;

[0010] Step S02, a first silane coupling agent is added to the system after ultrasonic treatment, and the pH of the system is adjusted to 5.5-6.5;

[0011] Step S03, a second silane coupling agent is added to the system after pH adjustment, and stirred and reacted at 40-50℃ for 2-3h, then a bisphenol A type epoxy resin is added, and stirred for 1-2h to prepare the modified fiber;

[0012] The fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber, and the volume ratio of polyethylene fiber to polyvinyl alcohol fiber is (1-3):1.

[0013] Further, the diameter of the polyethylene fiber is 15-25μm, the length of the polyethylene fiber is 10-14mm, the tensile strength of the polyethylene fiber is 2400-2600MPa, and the elastic modulus of the polyethylene fiber is 110-130Gpa.

[0014] Further, the diameter of the polyethylene fiber is 15-25μm, the length of the polyethylene fiber is 10-14mm, the tensile strength of the polyethylene fiber is 2400-2600MPa, and the elastic modulus of the polyethylene fiber is 110-130Gpa.

[0015] Further, the first silane coupling agent is selected from one or more of trimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-methoxypropyltrimethoxysilane.

[0016] Further, the second silane coupling agent is selected from one or more of trimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-methoxypropyltrimethoxysilane.

[0017] Further, the power of ultrasonic treatment is 0.5W / cm 2 -1W / cm 2 , and the time is 5-10min.

[0018] Further, the mass fraction of ethanol in the ethanol aqueous solution is 70%-80%.

[0019] Further, in the fly ash, the content of SiO2 is 50%-55%, the content of Al2O3 is 30%-32%, and the content of CaO is 3%-5%, in terms of weight percentage of fly ash.

[0020] Preferably, the specific gravity of the fly ash is 2-2.5, and the particle size is 40-60μm.

[0021] Further, the content of SiO2 in the slag is 32% to 36% by weight percentage of the slag, the content of Al2O3 is 16% to 20% by weight percentage of the slag, and the content of CaO is 33% to 35% by weight percentage of the slag.

[0022] Preferably, the specific gravity of the slag is 2.5 to 3, and the particle size is 10 to 20 μm.

[0023] Preferably, the mass ratio of the fly ash to the slag is (1 to 1.5) : 1.

[0024] Further, the mass ratio of the fibrous material, the ethanol aqueous solution, the first silane coupling agent, the second silane coupling agent, and the bisphenol A type epoxy resin is 20 to 30 : 50 : 1 to 5 : 1 to 5 : 1 to 10.

[0025] Further, the alkali activator is obtained by mixing a sodium silicate solution with a modulus of 2 to 2.5 and an 8 to 12 mol / L sodium hydroxide solution in a volume ratio of (1.5 to 2.5) : 1, and the content of SiO2 in the sodium silicate solution is 20% to 40% by weight percentage of the sodium silicate solution.

[0026] According to another aspect of the present application, a method for preparing the fibrous reinforced high-performance geopolymer concrete as above is provided, comprising the following steps:

[0027] Step S1, stirring and mixing barium chloride, fly ash, slag, and quartz powder to obtain a mixture;

[0028] Step S2, under stirring, sequentially adding an alkali activator and water into the mixture to obtain a mixture;

[0029] Step S3, adding modified fibers into the mixture to obtain the fibrous reinforced high-performance geopolymer concrete.

[0030] Preferably, in step S1, the stirring speed is 76 to 80 r / min, and the stirring time is 2 to 5 min.

[0031] Preferably, in step S2, the alkali activator and water are sequentially added within 1 to 2 min under a stirring speed of 76 to 80 r / min, and after the addition is completed, the stirring speed is adjusted to 135 to 140 r / min for 1 to 2 min to obtain the mixture.

[0032] Preferably, in step S3, the modified fibers are added into the mixture within 1 to 2 min under a stirring speed of 76 to 80 r / min, and then the stirring is performed for 1 to 2 min under a stirring speed of 76 to 80 r / min to obtain the fibrous reinforced high-performance geopolymer concrete.

[0033] According to another aspect of the present application, there is provided the use of the fiber reinforced high performance geopolymer concrete as above or the hardened product of the fiber reinforced high performance geopolymer concrete prepared according to the method as above in construction.

[0034] According to still another aspect of the present application, there is provided a construction material comprising the fiber reinforced high performance geopolymer concrete as above or the hardened product of the fiber reinforced high performance geopolymer concrete prepared according to the method as above.

[0035] Preferably, the fiber reinforced high performance geopolymer concrete is poured into a mold and vibrated into shape on a vibrating table, the surface of the shaped concrete is smoothed, and then the surface is coated and cured for 24-28 hours, after which the hardened product is obtained by curing for 24-32 days at a temperature of 18-22℃ and a relative humidity of 92-98%.

[0036] The technical scheme of the present application uses slag and coal ash and other waste materials as main raw materials, and through raw material proportioning and the incorporation of modified polyethylene fibers and modified polyethylene alcohol fibers, high performance geopolymer concrete with high tensile strength and good toughness is prepared. The incorporation of modified polyethylene fibers can improve the tensile toughness of the concrete material, but has limited effect on the initial cracking stress, and excessive addition of modified polyethylene fibers can easily increase the crack density in the initial cracking concrete product. The separate addition of modified polyethylene alcohol can improve the initial cracking stress of the concrete material and reduce the crack density in the initial cracking concrete product, but significantly reduces the tensile toughness of the concrete and increases the crack width in the initial cracking concrete product. The two are used together and proportioned, and the beneficial synergistic effect of the two on strength and toughness in the crack resistance process is exerted, and high performance geopolymer concrete with high tensile strength and good toughness is prepared. In addition, the fiber reinforced high performance geopolymer concrete of the present application is simple to prepare, has low requirements for equipment and production conditions, and has low difficulty in industrial production.

[0037] The fiber reinforced high performance geopolymer concrete of the present application can obtain a concrete material with both high toughness and high strength, and has simple process and broad application prospect. DETAILED DESCRIPTION

[0038] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0039] As described in the background, the prior art has the problem of poor toughness and easy cracking of geopolymer concrete, in order to solve the above problem, according to one aspect of the present application, a kind of fiber reinforced high performance geopolymer concrete is provided, comprising the following raw materials: fly ash, slag, quartz powder, alkali activator, barium chloride, water and modified fiber;The mass ratio of fly ash, slag, quartz powder, alkali activator, barium chloride and water is 620.3-849.7:364.1-620.3:242.8-248.1:485.5-496.2:72.8-74.3:12.1-12.4;The content of modified fiber is 1%-2% in terms of volume percentage of fiber reinforced high performance geopolymer concrete;Modified fiber is prepared by the following steps: step S01, fiber material is placed in ethanol aqueous solution for ultrasonic treatment;Step S02, first silane coupling agent is added to the system after ultrasonic treatment and the pH of the system is adjusted to 5.5-6.5;Step S03, second silane coupling agent is added to the system after adjusting pH, and stirred at 40-50 DEG C for 2-3 h, then bisphenol A type epoxy resin is added, and continue to stir for 1-2 h, to obtain modified fiber;Fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber, and the volume ratio of polyethylene fiber and polyvinyl alcohol fiber is (1-3):1.

[0040] In order to obtain a concrete material with toughness and high strength, the present application provides a kind of fiber reinforced high performance geopolymer concrete, and by the incorporation of modified polyethylene fiber and modified polyethylene alcohol fiber, the high performance geopolymer concrete with high tensile strength and good toughness is prepared by raw material ratio and waste such as slag and fly ash as main raw material;The introduction of modified polyethylene fiber can improve the tensile toughness of concrete material, but the initial cracking stress is limited, and too much modified polyethylene fiber can easily increase the crack density of initial cracking concrete product;And the separate addition of modified polyethylene alcohol can improve the initial cracking stress of concrete material and reduce the crack density in initial cracking concrete product, but it can significantly reduce the tensile toughness of concrete and increase the crack width in initial cracking concrete product, the two are used together and by the ratio of the two, the beneficial synergistic effect of the two on strength and toughness in crack resistance process is played, and the high performance geopolymer concrete with high tensile strength and good toughness is prepared;Wherein, the PVA fiber is placed in ethanol aqueous solution and treated by ultrasonic wave, on the one hand, the mechanical vibration of ultrasonic wave increases the micro roughness of fiber surface, so as to improve the surface activity, the first silane coupling agent is added and the pH value is controlled, the first silane coupling agent is hydrolyzed in aqueous environment to form silanol group, on the one hand, it reacts with the hydroxyl group on the surface of fiber to form stable Si-O-C bond structure, and on the other hand, it is used for subsequent reaction;The second silane coupling agent reacts with the generated silanol group to form Si-O-Si bond, forming a two-dimensional crosslinking network on the surface of fiber, and the active groups on the polyethylene alcohol fiber react with bisphenol A type epoxy resin to form a three-dimensional crosslinking network, and the modified PVA fiber is obtained, which can react with silicate in fly ash to improve the bonding strength between modified fiber and concrete in the form of chemical bond;In the process of PVA fiber modification, polyethylene fiber is introduced and modified with PVA fiber, which is beneficial to improve the uniformity of PVA fiber and PE fiber in modified fiber and improve the mechanical properties of concrete material.

[0041] In order to improve the load capacity of concrete material and improve the uniformity of fiber dispersion, improve the strength and toughness of concrete material, in some embodiments, the diameter of polyethylene fiber is 15-25 μm, the length of polyethylene fiber is 10-14 mm, the tensile strength of polyethylene fiber is 2400-2600 MPa, and the elastic modulus of polyethylene fiber is 110-130 Gpa.

[0042] In order to further improve the strength and toughness of concrete material, in some embodiments, the diameter of polyethylene alcohol fiber is 10-20 μm, the length of polyethylene alcohol fiber is 10-14 mm, the tensile strength of polyethylene alcohol fiber is 1700-1900 MPa, and the elastic modulus of polyethylene alcohol fiber is 40 GPa.

[0043] In some embodiments, the first silane coupling agent is selected from one or more of trimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-methoxypropyltrimethoxysilane.

[0044] In some embodiments, the second silane coupling agent is selected from one or more of trimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-methoxypropyltrimethoxysilane.

[0045] In some embodiments, the power of the ultrasonic treatment is 0.5 W / cm 2 ~ 1 W / cm 2 and the time is 5-10 min, so as to obtain a higher surface activity of the fiber material.

[0046] In some embodiments, the mass fraction of ethanol in the aqueous ethanol solution is 70%-80%.

[0047] In some embodiments, the components and proportions of the fly ash and the slag affect the fluidity, tensile toughness, and compressive strength of the concrete mixture. In order to facilitate molding and obtain a concrete material with higher tensile toughness and compressive strength, the content of SiO2 in the fly ash is 50%-55% by weight percentage of the fly ash, the content of Al2O3 is 30%-32% by weight percentage of the fly ash, and the content of CaO is 3%-5% by weight percentage of the fly ash; preferably, the specific gravity of the fly ash is 2-2.5, and the particle size is 40-60 μm; preferably, the content of SiO2 in the slag is 32%-36% by weight percentage of the slag, the content of Al2O3 is 16%-20% by weight percentage of the slag, and the content of CaO is 33%-35% by weight percentage of the slag; preferably, the specific gravity of the slag is 2.5-3, and the particle size is 10-20 μm; and preferably, the mass ratio of the fly ash to the slag is (1-1.5):1, so as to obtain higher tensile toughness and compressive strength.

[0048] In some embodiments, the mass ratio of the fiber material, the ethanol in the aqueous ethanol solution, the first silane coupling agent, the second silane coupling agent, and the bisphenol A type epoxy resin is 20-30:50:1-5:1-5:1-10.

[0049] In some embodiments, the alkali activator is obtained by mixing a sodium silicate solution with a modulus of 2-2.5 and an 8-12 mol / L sodium hydroxide solution in a volume ratio of (1.5-2.5):1, and the content of SiO2 in the sodium silicate solution is 20%-40% by weight percentage of the sodium silicate solution; preferably, the sodium silicate solution with a modulus of 2-2.5 is mixed with a 10 mol / L sodium hydroxide solution in a volume ratio of 2:1, the mixture is stirred thoroughly, sealed, and stored to cool, so as to obtain the alkali activator.

[0050] According to another aspect of the present application, there is provided a method for preparing the fiber reinforced high-performance geopolymer concrete as above, comprising the following steps: step S1, mixing barium chloride, fly ash, slag and quartz powder to obtain a mixture; step S2, adding an alkaline activator and water into the mixture under stirring to obtain a mixture; and step S3, adding modified fibers into the mixture and stirring to obtain the fiber reinforced high-performance geopolymer concrete. The method for preparing the fiber reinforced high-performance geopolymer concrete only needs to mix the components to obtain the fiber reinforced high-performance geopolymer concrete, and the process is simple. In the step S1, the stirring speed is preferably 76-80 r / min, and the stirring time is preferably 2-5 min. In the step S2, the alkaline activator and water are added into the mixture under the stirring speed of 76-80 r / min within 1-2 min, and after the addition is completed, the stirring speed is adjusted to 135-140 r / min for 1-2 min to obtain the mixture. In the step S3, the modified fibers are added into the mixture under the stirring speed of 76-80 r / min within 1-2 min, and then the mixture is stirred under the stirring speed of 76-80 r / min for 1-2 min to obtain the fiber reinforced high-performance geopolymer concrete.

[0051] According to still another aspect of the present application, there is provided a building material, comprising the concrete as above or the hardened product of the fiber reinforced high-performance geopolymer concrete prepared according to the method as above.

[0052] Preferably, the fiber reinforced high-performance geopolymer concrete is poured into a mold and moved to a vibrating table for vibration molding, the surface of the molded concrete is smoothed, and then the surface is coated and cured for 24-28 h. After demolding, the hardened product is cured for 24-32 days under the temperature of 18-22 ℃ and the relative humidity of 92-98% to obtain the hardened product.

[0053] The present application will be further described in detail below with reference to specific examples, which should not be construed as limiting the scope of the present application.

[0054] The raw materials or reagents used in the examples and comparative examples are commercially available unless otherwise specified. Among them, the components and parameters of some raw materials in the examples and comparative examples of the present application are as follows: the fly ash is F-grade fly ash produced by Gongyi Longze Water Purification Material Co., Ltd., the specific gravity is 2.3, the average particle size is 53.80 μm, and the specific chemical component composition and content (each component accounts for the weight percentage of fly ash) are shown in Table 1; the slag is blast furnace S105 slag produced by Gongyi Longze Water Purification Material Co., Ltd., the specific gravity is 2.9, the average particle size is 15.44 μm, and the specific chemical component composition and content (each component accounts for the weight percentage of slag) are shown in Table 2; the polyethylene fiber is a commercially available product of Evonik, and the physical performance parameters of the polyethylene fiber are shown in Table 3; the polyvinyl alcohol fiber is a commercially available product of Changzhou Tianyi Engineering Fiber Co., Ltd., and the physical performance parameters of the polyvinyl alcohol fiber are shown in Table 4; the water glass (sodium silicate solution) is a commercially available product of Jiashan Yourui Refractory Material Co., Ltd., and the main parameters are shown in Table 5; the sodium hydroxide is flaky sodium hydroxide with a purity of 96% produced by Xilong Scientific Co., Ltd.; the quartz sand is ordinary river sand, No. 9 sand, the specific gravity is 2.65, and the average diameter is 110 μm; the bisphenol A type epoxy resin is a commercially available product of Dongduo Chemical Co., Ltd., and the model number is DER-332.

[0055] Table 1. Chemical composition of fly ash

[0056]

[0057] Table 2. Chemical composition of slag

[0058] Chemical composition CaO SiO2 Al2O3 SO3 Fe2O3 MgO Others Content (%) 34.00 34.50 17.70 1.64 1.03 6.01 5.12

[0059] Table 3. Physical performance parameters of polyethylene fiber

[0060]

[0061] Table 4. Physical performance parameters of polyvinyl alcohol fiber

[0062]

[0063] Table 5. Main parameters of water glass

[0064] Modulus 1.00 0.00 0.00 0.00 0.00 0.00 0 Density (g / cm 3 )]]> SiO2(%) Na20 (%) 2.25 1.5 29.99 13.75

[0065] Example 1

[0066] A preparation method of a hybrid PE-PVA fiber reinforced high-performance geopolymer concrete:

[0067] Step one, preparation of modified fiber, the specific steps are as follows:

[0068] Step 1.1, place the fiber material in an ethanol aqueous solution, 0.5 W / cm2 ultrasonic treatment for 5 min; wherein the mass fraction of ethanol in the aqueous ethanol solution is 75%;

[0069] Step 1.2, adding trimethoxysilane to the ultrasonic-treated system and adjusting the pH of the system to 6;

[0070] Step 1.3, adding 3-methoxypropyltrimethoxysilane to the system after adjusting the pH, stirring at 40℃ for 2h, then adding bisphenol A type epoxy resin, and continuing to stir for 1h to obtain the modified fiber;

[0071] wherein the mass ratio of the fiber material, ethanol in the aqueous ethanol solution, trimethoxysilane, 3-methoxypropyltrimethoxysilane, and bisphenol A type epoxy resin is 20:50:2:2:5;

[0072] Step two, concrete preparation, the specific steps are as follows:

[0073] Step 2.1, mixing barium chloride, fly ash, slag, and quartz powder, stirring at a speed of 76r / min for 2min;

[0074] Step 2.2, continuing to stir at a speed of 76r / min for 1min and sequentially adding an alkaline activator and water during the stirring process, and after the stirring process is completed, adjusting the speed to 135r / min for rapid stirring for 1min to obtain a mixture;

[0075] Step 2.3, adjusting the speed to 76r / min for stirring, adding the modified fiber to the mixture within 1min, and then stirring at a speed of 76r / min for 1min to obtain the fiber-reinforced high-performance geopolymer concrete; wherein the dosage of the modified fiber is 2% based on the volume percentage of the fiber-reinforced high-performance geopolymer concrete;

[0076] wherein the alkaline activator is prepared by the following method: mixing a sodium silicate solution with a modulus of 2.25 and a 10mol / L sodium hydroxide solution according to a volume ratio of 2:1, fully stirring, sealing, and storing for cooling, and then using for pouring;

[0077] The mass ratio of fly ash, slag, quartz powder, alkaline activator, barium chloride, and water is 849.7:364.1:242.8:485.5:72.8:12.1.

[0078] The fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber in a volume ratio of 3:1.

[0079] Example 2

[0080] The difference from Example 1 is that in Step 1, the fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber mixed in a volume ratio of 2:1.

[0081] Example 3

[0082] The difference from Example 1 is that in Step 1, the fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber mixed in a volume ratio of 1:1.

[0083] Example 4

[0084] The difference from Example 1 is that in Step 2, the mass ratio of fly ash, slag, quartz powder, alkali activator, barium chloride and water is 736.3:490.9:245.4:490.9:73.6:12.3.

[0085] Example 5

[0086] The difference from Example 1 is that in Step 2, the mass ratio of fly ash, slag, quartz powder, alkali activator, barium chloride and water is 620.3:620.3:248.1:496.2:74.3:12.4.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that in Step 1, the fiber material is all polyethylene fiber, and the dosage of modified fiber is 1%.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that in Step 1, the fiber material is all polyethylene fiber, and the dosage of modified fiber is 1.5%.

[0091] Comparative Example 3

[0092] The difference from Example 1 is that in Step 1, the fiber material is all polyethylene fiber, and the dosage of modified fiber is 2.0%.

[0093] Comparative Example 4

[0094] The difference from Example 1 is that in Step 1, the fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber mixed in a volume ratio of 1:3.

[0095] Comparative Example 5

[0096] The difference from Example 1 is that in Step 1, the fiber material is all polyvinyl alcohol fiber.

[0097] Comparative Example 6

[0098] The difference from Example 1 is that in step two, no fiber material is added during the preparation of the concrete, and the specific steps are as follows:

[0099] Step 1.1, mix barium chloride, fly ash, slag, quartz powder, stir at a speed of 76 r / min for 2 min;

[0100] Step 1.2, continue to stir at a speed of 76 r / min for 1 min and add alkaline activator and water in sequence during stirring, after the stirring process is completed, adjust the speed to 135 r / min for rapid stirring for 1 min, to obtain the mixture;

[0101] Step 1.3, adjust the speed to 76 r / min for stirring, then stir at a speed of 76 r / min for 1 min, to obtain the geopolymer concrete;

[0102] The alkaline activator is prepared by the following method:

[0103] Mix the sodium silicate solution with a modulus of 2.25 and the 10 mol / L sodium hydroxide solution according to the volume ratio of 2:1, stir thoroughly, seal, and store for cooling before pouring;

[0104] The mass ratio of fly ash, slag, quartz powder, alkaline activator, barium chloride and water is 849.7:364.1:242.8:485.5:72.8:12.1.

[0105] Comparative Example 7

[0106] The difference from Example 1 is that in step one, no fiber modification is performed, and polyethylene fiber and polyvinyl alcohol fiber are directly used for concrete preparation, and the specific steps are as follows:

[0107] Step 1.1, mix barium chloride, fly ash, slag, quartz powder, stir at a speed of 76 r / min for 2 min;

[0108] Step 1.2, continue to stir at a speed of 76 r / min for 1 min and add alkaline activator and water in sequence during stirring, after the stirring process is completed, adjust the speed to 135 r / min for rapid stirring for 1 min, to obtain the mixture;

[0109] Step 1.3, adjust the speed to 76 r / min for stirring, then stir at a speed of 76 r / min for 1 min, to obtain the geopolymer concrete;

[0110] The alkaline activator is prepared by the following method:

[0111] The sodium silicate solution with modulus of 2.25 is mixed with 10 mol / L sodium hydroxide solution at a ratio of 2:1. The prepared sodium hydroxide solution and sodium silicate solution are mixed, stirred thoroughly, resealed, and stored for cooling, and used for pouring;

[0112] The mass ratio of fly ash, slag, quartz powder, alkali activator, barium chloride and water is 849.7:364.1:242.8:485.5:72.8:12.1.

[0113] The fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber at a volume ratio of 3:1.

[0114] The performance of the concrete prepared in Examples 1-5 and Comparative Examples 1-7 is tested:

[0115] I. Static tensile test

[0116] The static axial tension test piece is designed according to JCT2461-2018, and the static tensile test is carried out according to the standard "Mechanical Properties Test Methods of High Ductility Fiber Reinforced Cementitious Composites" (Standard) using a microcomputer-controlled electronic universal testing machine. The initial cracking stress and tensile toughness are shown in Table 6.

[0117] Crack width and density measurement: On the initial cracking test piece in the static tensile test, a segment with relatively uniform crack distribution is taken, and a line is drawn. The length of the line is 30 mm. Within this interval, the crack width and number are measured using a microscope. The average crack width and average crack density (i.e. the number of cracks per unit length) test results are shown in Table 7.

[0118] II. Axial static compression test

[0119] The static axial compression test piece is designed according to the standard "Standard for Mechanical Properties Test Methods of Ordinary Concrete" ASTM-C39, and the axial static compression test is carried out according to the ASTM-C39 standard using a voltage servo force testing machine (model MATEST C088-01). The compressive strength and elastic modulus of the test piece are shown in Table 8.

[0120] Table 6. Test results of initial cracking stress and tensile toughness of concrete materials

[0121]

[0122]

[0123] From Table 6, it can be seen that the concrete prepared in Examples 1-5 has both high initial cracking stress and tensile toughness. In the concrete material, the increase of the content of the modified polyethylene fiber can effectively improve the tensile toughness of the concrete, and the addition of an appropriate amount of modified polyvinyl alcohol fiber can significantly improve the initial cracking stress of the concrete while ensuring a high tensile toughness of the material, thereby obtaining a concrete material with both tensile toughness and tensile strength. In the concrete material, the addition of slag can improve the initial cracking stress of the concrete material and significantly improve the tensile toughness thereof.

[0124] From Comparative Examples 6 and 1-3, it can be seen that the increase of the addition and incorporation amount of the modified polyethylene fiber can effectively improve the tensile toughness of the concrete and improve the initial cracking stress of the concrete to a certain extent.

[0125] From Comparative Examples 6 and 5, it can be seen that the separate addition of the modified polyvinyl alcohol can increase the initial cracking stress of the concrete material from 2.31 MPa to 3.10 MPa, but significantly reduces the tensile toughness of the concrete, so that the tensile toughness of the concrete material is reduced from 14.20 kJ / m 3 to 0.43 kJ / m 3 .

[0126] From Comparative Example 3 and Examples 1-3, it can be seen that replacing a certain amount of modified polyethylene fiber with polyvinyl alcohol fiber can significantly improve the initial cracking stress of the concrete, and the obtained concrete has high tensile toughness.

[0127] From Comparative Example 4 and Examples 1-3, it can be seen that excessive addition of polyvinyl alcohol fiber can significantly reduce the tensile toughness of the concrete. For example, when the volume ratio of the modified polyethylene fiber to the polyvinyl alcohol fiber is 1:3 (see Comparative Example 4), the tensile toughness of the concrete is only 1.71 kJ / m

[0128] From Examples 3, 4, and 5, it can be seen that the increase of the slag content significantly improves the tensile toughness of the concrete. Compared with Example 3, the tensile toughness of the concrete in Examples 4 and 5 is improved by 16.6% and 11.9%, respectively, and the tensile toughness of the concrete material is significantly improved.

[0129]

[0130]

[0131] As shown in Table 7, the initial cracking products of the concrete prepared in Examples 1-5 have small crack width and crack density. In the preparation of the concrete material, the addition of the modified polyethylene fiber can reduce the crack width, but with the increase of the amount of the modified polyethylene fiber, the crack density increases. The separate addition of the modified polyethylene alcohol fiber can reduce the crack density, but significantly increases the crack width. In the concrete prepared in Examples 1-5, the addition of the two fibers of the modified polyethylene fiber and the polyethylene alcohol fiber and the adjustment of the ratio of the two fibers can achieve a good complementary effect, thereby reducing the crack width and crack density of the concrete cracking.

[0132] As shown in Comparative Example 6 and Comparative Examples 1-3, the separate addition of the modified polyethylene fiber can reduce the crack width, but with the increase of the amount of the modified polyethylene fiber, the crack density increases.

[0133] As shown in Comparative Example 6 and Comparative Example 5, the separate addition of the modified polyethylene alcohol can reduce the crack density of the concrete material, but significantly increases the crack width.

[0134] As shown in Comparative Example 3 and Examples 1-3, the replacement of a certain amount of the modified polyethylene fiber with the polyethylene alcohol fiber can obtain the concrete material with low crack width and crack density.

[0135] As shown in Comparative Example 4 and Examples 1-3, the excessive addition of the polyethylene alcohol fiber can increase the crack density.

[0136] Table 8. Test results of the compressive strength and elastic modulus of the concrete material

[0137]

[0138]

[0139] As shown in Table 6, the concrete prepared in Examples 1-5 has high compressive strength and high elastic modulus. As shown in Examples 3-5, the compressive strength and elastic modulus of the concrete material increase with the increase of the content of the slag. The elastic modulus of the concrete in Example 5 is increased by 23% compared with the elastic modulus of the concrete in Example 3.

[0140] From the above description, it can be seen that the concrete prepared in the above examples of the present application has high initial cracking stress, tensile toughness and high compressive strength, and the crack width and crack density of the tensile cracking are low, which has a good application prospect.

[0141] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A fiber reinforced high performance geopolymer concrete, characterized in that, The raw materials include fly ash, slag, quartz powder, alkali activator, barium chloride, water and modified fiber; The mass ratio of the fly ash, the slag, the quartz powder, the alkali activator, the barium chloride and the water is 620.3-849.7:364.1-620.3:242.8-248.1:485.5-496.2:72.8-74.3:12.1-12.4; The content of the modified fiber is 1%-2% in terms of volume percentage of the fiber reinforced high-performance polymer concrete; The modified fiber is prepared by the following steps: Step S01, the fiber material is placed in an ethanol aqueous solution for ultrasonic treatment; Step S02, a first silane coupling agent is added to the system after ultrasonic treatment and the pH of the system is adjusted to 5.5-6.5; Step S03, a second silane coupling agent is added to the system after pH adjustment, stirring and reaction are carried out at 40-50℃ for 2-3h, then a bisphenol A type epoxy resin is added, and stirring is continued for 1-2h, thus the modified fiber is prepared; The fiber material is a mixture of polyethylene fiber and polyvinyl alcohol fiber, and the volume ratio of the polyethylene fiber to the polyvinyl alcohol fiber is (1-3):

1.

2. The fiber reinforced high performance geopolymer concrete according to claim 1, characterized in that, The diameter of the polyethylene fiber is 15-25μm, the length of the polyethylene fiber is 10-14mm, the tensile strength of the polyethylene fiber is 2400-2600MPa, and the elastic modulus of the polyethylene fiber is 110-130Gpa; and / or, The diameter of the polyvinyl alcohol fiber is 10-20μm, the length of the polyvinyl alcohol fiber is 10-14mm, the tensile strength of the polyvinyl alcohol fiber is 1700-1900MPa, and the elastic modulus of the polyvinyl alcohol fiber is 40Gpa; and / or, The power of the ultrasonic treatment is 0.5 W / cm 2 ~ 1 W / cm 2 , and the time is 5~10 min; and / or, The mass fraction of ethanol in the ethanol aqueous solution is 70%-80%.

3. The fiber reinforced high performance geopolymer concrete according to claim 1, characterized in that, The first silane coupling agent is selected from one or more of trimethoxysilane, 3-aminopropyltrimethoxysilane and 3-methoxypropyltrimethoxysilane; and / or, The second silane coupling agent is selected from one or more of trimethoxysilane, 3-aminopropyltrimethoxysilane and 3-methoxypropyltrimethoxysilane.

4. The fiber reinforced high performance geopolymer concrete as claimed in claim 1, wherein, The content of SiO2 in the fly ash is 50%-55% in terms of weight percentage of the fly ash, the content of Al2O3 is 30%-32%, and the content of CaO is 3%-5%.

5. The fiber reinforced high performance geopolymer concrete according to claim 4, characterized in that, The specific gravity of the fly ash is 2-2.5, and the particle size is 40-60μm.

6. The fiber reinforced high performance geopolymer concrete as claimed in claim 1, wherein, The content of SiO2 in the slag is 32%-36% in terms of weight percentage of the slag, the content of Al2O3 is 16%-20%, and the content of CaO is 33%-35%.

7. The fiber reinforced high performance geopolymer concrete according to claim 6, characterized in that, At least one of the following characteristics is met: (1) the specific gravity of the slag is 2.5-3, and the particle size is 10-20μm; (2) the mass ratio of the fly ash to the slag is (1-1.5):

1.

8. The fiber reinforced high performance geopolymer concrete as claimed in claim 1, wherein, The mass ratio of the fiber material, ethanol in the aqueous ethanol solution, the first silane coupling agent, the second silane coupling agent, and the bisphenol A type epoxy resin is 20-30:50:1-5:1-5:1-10.

9. The fiber reinforced high performance geopolymer concrete according to any one of claims 1 to 8, characterized in that, The alkali activator is obtained by mixing a sodium silicate solution with a modulus of 2-2.5 and an 8-12 mol / L sodium hydroxide solution in a volume ratio of (1.5-2.5):1; the content of SiO2 in the sodium silicate solution is 20%-40% by weight of the sodium silicate solution.

10. The method of producing fiber reinforced high performance geopolymer concrete according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: Step S1, stirring and mixing barium chloride, fly ash, slag, and quartz powder to obtain a mixture; Step S2, under stirring, adding an alkali activator and water into the mixture in sequence to obtain a mixture; Step S3, adding modified fibers into the mixture and stirring to obtain the fiber-reinforced high-performance geopolymer concrete.

11. The method of producing fiber reinforced high performance geopolymer concrete according to claim 10, characterized in that, At least one of the following conditions is met: (1) In the step S1, the stirring speed is 76-80 r / min, and the stirring time is 2-5 min; (2) In the step S2, the alkali activator and water are added into the mixture in sequence under a stirring speed of 76-80 r / min within 1-2 min, and after the addition is completed, the stirring speed is adjusted to 135-140 r / min for 1-2 min to obtain the mixture; (3) In the step S3, the modified fibers are added into the mixture under a stirring speed of 76-80 r / min within 1-2 min, and then the mixture is stirred at a stirring speed of 76-80 r / min for 1-2 min to obtain the fiber-reinforced high-performance geopolymer concrete.

12. Use of the fiber-reinforced high-performance geopolymer concrete according to any one of claims 1-9 or prepared according to the method of any one of claims 10-11 in construction.

13. A building material, characterized by A hardened product comprising the fiber-reinforced high-performance geopolymer concrete according to any one of claims 1-9 or prepared according to the method of any one of claims 10-11.

14. The construction material of claim 13, wherein, The fiber-reinforced high-performance geopolymer concrete is poured into a mold and vibrated on a vibrating table to form, the surface of the formed concrete is smoothed, and then a surface film is applied for curing for 24-28 h; after demolding, the hardened product is obtained by curing for 24-32 days at a temperature of 18-22°C and a relative humidity of 92%-98%.

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