Concrete reinforced by wollastonite microfiber composite mineral admixture and preparation method thereof

Abstract

The invention discloses wollastonite microfiber composite mineral admixture reinforced concrete and a preparation method thereof, and belongs to the technical field of concrete preparation. The invention solves the problems of high cost, complex process, limited performance improvement, poor environmental protection property and the like of the current concrete modification mode. The concrete formula comprises wollastonite microfibers, silica fume, redispersible latex powder, a water reducing agent, cement and aggregate. Or comprises wollastonite microfibers, silica fume, polypropylene fibers, cement and aggregate; or the wollastonite microfibers, the granulated blast furnace slag powder, the polypropylene fibers, the sodium silicate, the cement and the aggregate are included. The wollastonite microfiber disclosed by the invention has a micro-aggregate effect, and also can be used for bridging cracks and improving the compressive strength and sulfate corrosion resistance of the concrete; the silica fume can be filled among cement particles to densify the concrete; the polypropylene fibers form a net-shaped structure in the concrete to support the aggregate; the granulated blast furnace slag powder and the sodium silicate have a mutual synergistic effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete preparation, and in particular to a wollastonite micro-fiber composite mineral admixture reinforced concrete and a preparation method thereof. BACKGROUND

[0002] Ordinary concrete is the most widely used and applied building material in the world today, and it plays an irreplaceable role in modern civil engineering. However, due to its inherent material properties, current ordinary concrete has significant defects such as high brittleness, low tensile strength, easy cracking, and insufficient durability. These defects may cause structural safety hazards under normal use conditions, and when the concrete structure is in a harsh environment such as chloride ion erosion and sulfate corrosion, the performance degradation process is even more rapid and significant, which seriously restricts the service life and safety reliability of the concrete. In particular, chloride ion penetration induced steel corrosion and sulfate erosion induced concrete expansion and spalling have become the main factors affecting the durability of reinforced concrete structures. In order to overcome the above-mentioned defects of ordinary concrete, the existing technology often uses single or simple combination of steel fibers, polypropylene fibers, silica fume, and mineral powder to improve the performance of concrete. However, the above modification methods still have the following problems: high cost: such as steel fiber, carbon fiber, etc. The price of the reinforcing material is relatively high; complex process: poor dispersion of fibers, easy to form clumps, affecting the construction performance; environmentally unfriendly: large amount of cement, high carbon emission; limited performance improvement: single admixture has a best dosage limit, and excessive use will lead to performance decline; insufficient durability: especially in terms of resistance to chloride ion penetration and sulfate attack, there is still a lot of room for improvement. In addition, the above modification methods often lack systematic synergistic effect design. Therefore, developing a new type of concrete technology that can comprehensively solve the contradiction between cost, process, environmental friendliness, and high performance, especially significantly improving the resistance to chloride ion penetration and sulfate attack, has become a key technical problem urgently needed to be solved in the field. SUMMARY

[0003] In order to solve the technical problems of current concrete modification methods such as high cost, complex process, limited performance improvement, and poor environmental friendliness, the present application provides a wollastonite micro-fiber composite mineral admixture reinforced concrete and a preparation method thereof.

[0004] To solve the above technical problems, the present application realizes the following technical scheme: One of the purposes of the present application is to provide a wollastonite microfiber composite mineral admixture reinforced concrete, which is prepared from a wollastonite microfiber modified mineral admixture, a re-dispersible latex powder (VAE), a water reducing agent (WR), cement and aggregate, wherein the wollastonite microfiber modified mineral admixture comprises wollastonite microfibers (WF) and silica fume (SF), the wollastonite microfibers replace 3-8% of cement by equal amount, the silica fume replaces 3-7% of cement by equal amount, the re-dispersible latex powder replaces 0-8% of cement by equal amount, the water reducing agent is used in an amount of 0.5-2% of cementitious materials, the total mass of the wollastonite microfiber modified mineral admixture, the re-dispersible latex powder, the water reducing agent, the cement and the aggregate before and after the wollastonite microfibers, the silica fume and the re-dispersible latex powder replacing by equal amount remains unchanged, the cementitious materials comprise cement and silica fume, and the water-cement ratio is 0.45-0.6.

[0005] Further limitation, the wollastonite microfibers replace 5% of cement by equal amount, the silica fume replaces 3-7% of cement by equal amount, the re-dispersible latex powder replaces 3-7% of cement by equal amount, the water reducing agent is used in an amount of 0.5-2% of cementitious materials; the total mass of the wollastonite microfiber modified mineral admixture, the re-dispersible latex powder, the water reducing agent, the cement and the aggregate before and after the wollastonite microfibers and the silica fume replacing by equal amount remains unchanged; the cementitious materials comprise cement and silica fume. Further limitation, the wollastonite microfibers replace 5% of cement by equal amount, the silica fume replaces 5% of cement by equal amount, the water reducing agent is used in an amount of 0.5% of cementitious materials; the total mass of the wollastonite microfiber modified mineral admixture, the water reducing agent, the cement and the aggregate before and after the wollastonite microfibers and the silica fume replacing by equal amount remains unchanged; the cementitious materials comprise cement and silica fume.

[0006] Further limitation, the aggregate comprises coarse aggregate and fine aggregate.

[0007] The second purpose of the present application is to provide a preparation method of the above-mentioned wollastonite microfiber composite mineral admixture reinforced concrete, which comprises the following steps: (1) wollastonite microfibers, silica fume, re-dispersible latex powder and cement are uniformly stirred in a concrete mixer to obtain mixed dry material 1; (2) fine aggregate and coarse aggregate are added to the mixed dry material 1 and continue to stir to obtain mixed dry material 2; (3) the water reducing agent is dissolved in water to prepare a water reducing agent solution, and the water reducing agent solution is poured into the mixed dry material 2 and stirred to obtain a slurry; (4) the slurry is poured into a mold, and after standing for 24 h, it is cured in a standard curing environment, and the concrete is obtained after curing.

[0008] Further limitation, the stirring time in (2) is 30 s.

[0009] Further limit, the stirring time in (3) is 2 min.

[0010] The third object of the present application is to provide a wollastonite microfiber composite mineral admixture reinforced concrete, which is prepared from a wollastonite microfiber modified mineral admixture, polypropylene fiber (PPF), cement and aggregate, wherein the wollastonite microfiber modified mineral admixture comprises wollastonite microfiber and silica fume, the wollastonite microfiber replaces 5-20% of cement by equal amount, the silica fume replaces 3-9% of cement by equal amount, the amount of polypropylene fiber is 0.05-0.2% of cementitious material, the total mass of the wollastonite microfiber modified mineral admixture, polypropylene fiber, cement and aggregate remains unchanged before and after the wollastonite microfiber and silica fume are replaced by equal amount, the cementitious material comprises cement and silica fume, and the water-cement ratio is 0.45-0.6.

[0011] Further limit, the wollastonite microfiber replaces 10% of cement by equal amount, the silica fume replaces 7% of cement by equal amount, the amount of polypropylene fiber is 0.2% of cementitious material, the total mass of the wollastonite microfiber modified mineral admixture, polypropylene fiber, cement and aggregate remains unchanged before and after the wollastonite microfiber and silica fume are replaced by equal amount, the cementitious material comprises cement and silica fume, and the water-cement ratio is 0.45.

[0012] Further limit, the aggregate comprises coarse aggregate and fine aggregate.

[0013] The fourth object of the present application is to provide a preparation method of the wollastonite microfiber composite mineral admixture reinforced concrete of the third object, which comprises the following steps: (1) uniformly stirring wollastonite microfiber, silica fume, polypropylene fiber and cement in a concrete mixer to obtain mixed dry material 1; (2) adding fine aggregate and coarse aggregate to the mixed dry material 1 and continuing to stir to obtain mixed dry material 2; (3) stirring water into the mixed dry material 2 to obtain slurry; (4) pouring the slurry into a mold, placing for 24 h and then curing in a standard curing environment to obtain the concrete.

[0014] Further limit, the stirring time in (2) is 30 s.

[0015] Further limit, the stirring time in (3) is 2 min.

[0016] The fifth object of the present application is to provide a wollastonite microfiber composite mineral admixture reinforced concrete, which is prepared from a wollastonite microfiber modified mineral admixture, polypropylene fibers, sodium silicate (SSC), cement and aggregates, wherein the wollastonite microfiber modified mineral admixture comprises wollastonite microfibers and granulated blast furnace slag powder (GGBFS), the wollastonite microfibers replace 5-20% of the cement by equal amount, and the granulated blast furnace slag powder replaces 65-80% of the cement by equal amount, based on 100% of the cement; the amount of the polypropylene fibers is 0.05-0.2% of the cementitious materials, and the amount of the sodium silicate is 5.5-7% of the cementitious materials; the total mass of the wollastonite microfiber modified mineral admixture, the polypropylene fibers, the sodium silicate, the cement and the aggregates before and after the wollastonite microfibers and the granulated blast furnace slag powder are replaced by equal amount remains unchanged; the cementitious materials comprise the cement and the granulated blast furnace slag powder; and the water-cement ratio is 0.45-0.6.

[0017] Further limitation, the wollastonite microfibers replace 10% of the cement by equal amount, and the granulated blast furnace slag powder replaces 75% of the cement by equal amount, based on 100% of the cement; the amount of the polypropylene fibers is 0.2% of the cementitious materials, and the amount of the sodium silicate is 5.5% of the cementitious materials; the total mass of the wollastonite microfiber modified mineral admixture, the polypropylene fibers, the sodium silicate, the cement and the aggregates before and after the wollastonite microfibers and the granulated blast furnace slag powder are replaced by equal amount remains unchanged; and the cementitious materials comprise the cement and the granulated blast furnace slag powder.

[0018] Further limitation, the aggregates comprise coarse aggregates and fine aggregates.

[0019] The sixth object of the present application is to provide a preparation method of the wollastonite microfiber composite mineral admixture reinforced concrete of the fifth object, which comprises the following steps: (1) uniformly stirring the wollastonite microfibers, the granulated blast furnace slag powder, the polypropylene fibers and the cement in a concrete mixer to obtain mixed dry materials 1; (2) continuously stirring the fine aggregates and the coarse aggregates added into the mixed dry materials 1 to obtain mixed dry materials 2; (3) dissolving the sodium silicate in water to prepare a sodium silicate solution, and stirring the sodium silicate solution into the mixed dry materials 2 to obtain a slurry; (4) pouring the slurry into a mold, and curing in a standard curing environment after standing for 24 h to obtain the concrete.

[0020] Further limitation, the stirring time in (2) is 30 s.

[0021] Further limitation, the stirring time in (3) is 2 min.

[0022] The wollastonite microfiber composite mineral admixture reinforced concrete has the following advantages: The application provides a multi-scale and multi-component synergistically reinforced concrete, which is prepared by compounding microfibers of wollastonite, silica fume, microfibers of wollastonite and polypropylene fibers, microfibers of wollastonite and granulated blast furnace slag powder and the like, optimizing the mixing amount and process parameters, and significantly improving the comprehensive performance of the concrete. (1) The microfibers of wollastonite are inert materials and do not react with Ca (OH) 2, indirectly promote the hydration reaction through the micro aggregate effect and form a wrapped composite phase with the hydration product, so that the concrete is more compact and the internal chloride ion penetration is reduced. However, if the amount of the microfibers of wollastonite is too high, the compression strength improvement caused by the filling effect is not enough to offset the reduction of the hydration product caused by excessive replacement of cement, resulting in a dilution effect, a delay in the development of the compression strength of the concrete and a reduction in the compression strength of the concrete. Therefore, the amount of the microfibers of wollastonite needs to be controlled in a proper range, and in the three formulations, the microfibers of wollastonite are used to replace 3-8% and 5-20% of cement, respectively. The different amounts in different formulations are due to the different substances that synergize with the microfibers of wollastonite. In addition, the proper mixing amount and size of the WF and the fibrous structure of the WF can bridge the cracks, improve the interface area between the WF and the cement matrix to promote the hydration of the cement, and improve the compression strength and the sulfate resistance of the concrete.

[0023] (2) The silica fume SF of the application contains a large amount of amorphous SiO2, can react with Ca (OH) 2 to generate C-S-H gel and CH crystals in the early stage of the reaction, thereby improving the compression strength of the concrete. In addition, the SF has a micro aggregate effect and can be filled between the cement particles, thereby reducing the porosity of the concrete, making the concrete more compact, and further improving the compression strength of the concrete, reducing the internal chloride ion penetration of the concrete and improving the chloride ion penetration resistance of the concrete.

[0024] (3) The microfibers of wollastonite in the application can be used as a filler to improve the internal interface microstructure of the concrete, make the interface area more uniform and the microcracks smaller. The SF can promote the generation of the hydration product due to the high pozzolanic activity, and reduce the size of the internal pores of the concrete. Therefore, the combination of the WF and the SF causes the rearrangement and modification of the microstructure of the concrete in the physical and chemical aspects, and due to the micro aggregate effect of the SF and the WF, the density and quality of the interface transition zone of the concrete are improved, the internal structure of the concrete is more compact, the chloride ion penetration resistance is improved, the water absorption of the concrete is affected by the number of internal pores by the water reducing agent and the redispersible latex powder, the water reducing agent reduces the internal pores of the concrete, thereby reducing the water absorption of the concrete and improving the chloride ion penetration resistance.

[0025] (4) The polypropylene fibers of the present application are evenly distributed in the concrete to form a network structure, which supports the aggregate and prevents and delays the generation of internal micro-cracks and the expansion of crack stress accumulation, thereby improving the resistance of the concrete to chloride ion penetration. However, too much PPF will increase the thickness of the transition zone and the porosity of the concrete, resulting in a decrease in the resistance of the concrete to chloride ion penetration. Therefore, the polypropylene fibers need to be controlled within a suitable range, and the amount of polypropylene fibers in the present application is 0.05-0.2% of the cementitious materials in two formulations.

[0026] (5) Granulated blast furnace slag powder and sodium silicate have a synergistic effect, and as the content of GGBFS increases, more C-S-H and C-A-S-H gel will be produced inside and outside the particles, and will fill the inside of the dissolved particles and the surrounding of the still intact GGBFS particles. With the increase of gel products, they gradually wrap the particles and fill the blank parts, making the overall internal structure of the concrete gradually stable. However, when the content of sodium silicate is low, the alkali environment provided by the alkali solution is weak, and the reaction products are less, which cannot form a dense structure. However, when the content of sodium silicate is too high, the material migration rate is lost too quickly, and the setting and hardening time is greatly advanced, which leads to a large number of GGBFS particles being wrapped by hydration products before they are dissolved, and the diffusion of the dissolved Si-O and Al-O tetrahedral monomers is inhibited, which will not further react, thereby reducing the degree of polymerization of the concrete and making the internal structure of the concrete loose, which reduces the resistance of the concrete to chloride ion penetration. Therefore, the amount of sodium silicate needs to be controlled within a suitable range, and the amount of sodium silicate in the present application is 5.5-7% of the cementitious materials, which can improve the hydration reaction of GGBFS and promote the generation of more C-S-H gel.

[0027] (6) The present application optimizes the design and synergistic effect of each component, which significantly improves the comprehensive performance of the obtained concrete product, which is specifically manifested in: in terms of mechanical properties, the 28d compressive strength of the concrete is increased by 37.4% compared with the highest of Comparative Example 1, and the 28-day compressive strength can reach 47MPa; in terms of durability, the resistance of the concrete to chloride ion penetration is increased by 74% compared with the highest of Comparative Example 1, and the water absorption rate is reduced by 48.33% at the most; in terms of resistance to sulfate attack, after 120 times of dry-wet cycle erosion, the strength retention rate can still maintain more than 115%; in addition, the present application also has environmental protection and economy, which can replace cement in a large proportion, thereby reducing the carbon dioxide emissions in the cement production process from the source, and effectively reducing the production cost of raw materials. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the micro-morphology diagram of the concrete of Example 1; Figure 2 is the micro-morphology diagram of the concrete of Example 1 (different from Figure 1 the position). Figure 3 Micrograph of the concrete of Example 2; Figure 4 Micrograph of the concrete of Example 2 (with Figure 3 Position difference. DETAILED DESCRIPTION

[0029] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference made to the embodiments of the present application.

[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details presented herein. In other instances, well-known methods have not been described in detail in order to avoid obscuring aspects of the present application.

[0031] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. The "in one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is independent of or alternatively to other embodiments.

[0032] The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by commercial channels by those skilled in the art.

[0033] The cement used in the following examples and comparative examples is P.O 42.5 ordinary portland cement of Changchun Yatai Group, and the chemical composition is shown in Table 1; the size of the microfibers of wollastonite is passed through a 325 mesh sieve; the SiO2 content of the silica fume is 96%, and the chemical composition and specific surface area are shown in Table 2; Table 1 Chemical composition and content of cement

[0034] Table 2 Chemical composition and specific surface area of silica fume

[0035] The length of the polypropylene fibers is 12 mm, and the diameter is 18-48 μm, and the performance parameters are shown in Table 3; the performance indexes of the granulated blast furnace slag powder are shown in Table 4; Table 3 Performance parameters of polypropylene fibers

[0036] Table 4 Performance indexes of granulated blast furnace slag powder

[0037] The water reducing agent was purchased from Shanxi Feike New Material Technology Co., Ltd., and the model was HLX standard polycarboxylic acid high-performance water reducing agent mother liquor. The fine aggregate was natural river sand with a particle size of 0-4.75 mm, and the coarse aggregate was crushed stone with a particle size of 4.75-20 mm.

[0038] Example 1 The concrete in this example was prepared from a wollastonite-modified mineral admixture, a water reducing agent, cement, and aggregates, the wollastonite-modified mineral admixture including wollastonite microfibers and silica fume, the wollastonite microfibers being equivalent to 5% of the cement by mass, and the silica fume being equivalent to 5% of the cement by mass; the water reducing agent being 0.5% of the cementitious materials by mass, the total mass of the wollastonite-modified mineral admixture, the water reducing agent, the cement, and the aggregates being unchanged before and after the wollastonite microfibers and the silica fume were equivalent replacements; the cementitious materials including the cement and the silica fume; the coarse aggregate being 267% of the cement by mass; and the fine aggregate being 190% of the cement by mass, and the water-cement ratio being 0.45. Specifically, the concrete was prepared according to the following steps: (1) The wollastonite microfibers, the silica fume, and the cement were stirred uniformly in a concrete mixer to obtain mixed dry materials 1; (2) The fine aggregate and the coarse aggregate were added to the mixed dry materials 1 and stirred for 30 s to obtain mixed dry materials 2; (3) The water reducing agent was dissolved in water to obtain a water reducing agent solution, and the water reducing agent solution was poured into the mixed dry materials 2 and stirred for 2 min to obtain a slurry; (4) The slurry was poured into a mold and vibrated on a vibrating table to compact it, and after 24 h, the concrete was demolded and placed in a TYC-SCB standard curing box for curing. After the curing was completed, the concrete was obtained; The mold in step (4) of this example had two sizes, a 100 mm x 100 mm x 100 mm cube mold and a 100 mm x 50 mm cylindrical mold. The two mold sizes were used to subsequently test the compressive strength of the concrete (using the 100 mm x 100 mm x 100 mm cube mold) and the resistance to chloride ion penetration (using the 100 mm x 50 mm cylindrical mold). This method did not affect the performance of the concrete.

[0039] Example 2 The concrete in the embodiment is prepared from a wollastonite modified mineral admixture, polypropylene fiber, cement and aggregate, the wollastonite modified mineral admixture comprises wollastonite microfiber and silica fume, the wollastonite microfiber is equivalent to replace 10% of the cement, and the silica fume is equivalent to replace 7% of the cement; the amount of polypropylene fiber is 0.2% of the cementitious material, and the total mass of the wollastonite modified mineral admixture, polypropylene fiber, cement and aggregate before and after the wollastonite microfiber and silica fume are equivalent to replace is unchanged; the cementitious material comprises cement and silica fume, the amount of coarse aggregate is 267wt% of the cement, the amount of fine aggregate is 190wt% of the cement, and the water-cement ratio is 0.45. Specifically, it is prepared by the following steps: (1) wollastonite microfiber, silica fume, polypropylene fiber and cement are uniformly stirred in a concrete mixer to obtain mixed dry material 1; (2) fine aggregate and coarse aggregate are added to the mixed dry material 1 and continue to stir for 30s to obtain mixed dry material 2; (3) pour water into the mixed dry material 2 and stir for 2min to obtain slurry; (4) pour the slurry into the mold and compact it on the vibrating table, take it out after 24h and put it into a TYC-SCB standard curing box for curing, and then obtain the concrete after the curing is completed; The mold in step (4) of the embodiment has two sizes of 100mm×100mm×100mm cubic mold and 100mm×50mm cylindrical mold, and two mold sizes are used to subsequently test the compressive strength of the concrete (use 100mm×100mm×100mm cubic mold) and the resistance to chloride ion penetration (use 100mm×50mm cylindrical mold), which will not affect the performance of the concrete.

[0040] Example 3 The concrete in the embodiment is prepared from a wollastonite modified mineral admixture, polypropylene fiber, sodium silicate, cement and aggregate, the wollastonite modified mineral admixture comprises wollastonite microfiber and granulated blast furnace slag powder (GGBFS), the wollastonite microfiber is equivalent to replace 10% of the cement, and the granulated blast furnace slag powder is equivalent to replace 75% of the cement; the amount of polypropylene fiber is 0.2% of the cementitious material, and the amount of sodium silicate is 5.5% of the cementitious material; the total mass of the wollastonite modified mineral admixture, polypropylene fiber, sodium silicate, cement and aggregate before and after the wollastonite microfiber and granulated blast furnace slag powder are equivalent to replace is unchanged, the cementitious material comprises cement and granulated blast furnace slag powder, the amount of coarse aggregate is 267wt% of the cement, and the amount of fine aggregate is 190wt% of the cement; the water-cement ratio is 0.45. Specifically, it is prepared by the following steps: (1) Stir the wollastonite microfiber, granulated blast furnace slag powder, polypropylene fiber and cement uniformly in a concrete mixer to obtain mixed dry material 1; (2) Continue to stir the fine aggregate and coarse aggregate into the mixed dry material 1 for 30 s to obtain mixed dry material 2; (3) Dissolve sodium silicate in water to obtain a sodium silicate solution, and stir the sodium silicate solution into the mixed dry material 2 to obtain a slurry; (4) Pour the slurry into a mold and compact it on a vibrating table, demold it after 24 h of standing, and place it in a TYC-SCB standard curing box for curing. The concrete is obtained after the curing is completed. The mold in step (4) of this example has two sizes, a 100 mm x 100 mm x 100 mm cube mold and a 100 mm x 50 mm cylindrical mold. Two mold sizes are used to subsequently test the compressive strength of the concrete (using a 100 mm x 100 mm x 100 mm cube mold) and the resistance to chloride ion penetration (using a 100 mm x 50 mm cylindrical mold). This method does not affect the performance of the concrete.

[0041] Comparative Example 1 The ordinary concrete of this comparative example is prepared from cement, water reducing agent and aggregate. The amount of coarse aggregate is 267 wt% of cement, the amount of fine aggregate is 190 wt% of cement, and the amount of water reducing agent is 1 wt% of cementitious materials (cement). The water-cement ratio is 0.45. It is prepared according to the following steps: (1) Pour the cement into a concrete mixer and stir, then add the fine aggregate and coarse aggregate and continue to stir for 30 s to obtain a mixed dry material; (2) Stir the water into the mixed dry material to obtain a slurry; (3) Pour the slurry into a mold and compact it on a vibrating table, demold it after 24 h of standing, and place it in a TYC-SCB standard curing box for curing. The ordinary concrete is obtained after the curing is completed. The mold in step (4) of this example has two sizes, a 100 mm x 100 mm x 100 mm cube mold and a 100 mm x 50 mm cylindrical mold. Two mold sizes are used to subsequently test the compressive strength of the concrete (using a 100 mm x 100 mm x 100 mm cube mold) and the resistance to chloride ion penetration (using a 100 mm x 50 mm cylindrical mold). This method does not affect the performance of the concrete.

[0042] Detection Test (1) Concrete compressive strength test: The 28d compressive strength of the concrete of Examples 1-3 and Comparative Example 1 was measured according to the national standard GB / T 50081-2019 "Standard for Testing Methods of Physical and Mechanical Properties of Concrete". The method was to place the test block on a YES-3000 type press for continuous and uniform loading at a speed of 0.5-0.8 MPa / s until the test block deformed and failed, and the load at the time of failure was recorded. The 28d compressive strength of the concrete of Examples 1-3 and Comparative Example 1 was measured to be 39.2 MPa, 47.0 MPa, 44.8 MPa and 34.2 MPa, respectively.

[0043] (2) Concrete resistance to chloride ion penetration test: The electric flux of the concrete of Examples 1-3 and Comparative Example 1 was measured according to the industry standard JG / T 261-2009 "Concrete Chloride Ion Electric Flux Tester" to evaluate the resistance to chloride ion penetration of the concrete. The method was to dry the chloride ion test block after curing for a certain period of time, brush the cylindrical surface with paraffin wax, fill the holes on the surface of the test block, and then place the test block in a NEL-VJH type intelligent concrete vacuum water retaining machine for 24h. The NEL-PEU type concrete electric flux tester was used for testing, with 3% NaCl solution and 3 mol / L NaOH solution on the left and right sides of the test block, respectively. The electric flux was measured for 6h. The electric flux of the concrete of Examples 1-3 and Comparative Example 1 was measured to be 1998C, 1136.8C, 1095.1C and 4130.14C, respectively.

[0044] (3) Concrete water absorption test: The water absorption of the concrete of Examples 1-3 and Comparative Example 1 was measured according to the national standard GB / T 50081-2019 "Standard for Testing Methods of Physical and Mechanical Properties of Concrete". The method was to first immerse the test block in water at (20±2℃) for 48h, take it out and measure the saturated mass m s (24h was taken out for measurement once, and the mass change of the larger one was less than 0.2%), and then put it into a forced air drying oven for 48h to take out and measure the mass m d (24h was taken out for measurement once, and the mass change of the larger one was less than 0.2%), and then put it into a forced air drying oven for 48h to take out and measure the mass m a (24h was taken out for measurement once, and the mass change of the larger one was less than 0.2%), and then put it into a forced air drying oven for 48h to take out and measure the mass m s (24h was taken out for measurement once, and the mass change of the larger one was less than 0.2%), and then put it into a forced air drying oven for 48h to take out and measure the mass m d (24h was taken out for measurement once, and the mass change of the larger one was less than 0.2%), and then put it into a forced air drying oven for 48h to take out and measure the mass m d (24h was taken out for measurement once, and the mass change of the larger one was less than 0.2%), and then put it into a forced air drying oven for 48h to take out and measure the mass m a . The water absorption of the concrete of Examples 1-3 and Comparative Example 1 was measured to be 3.9%, 3.1%, 3.7% and 6%, respectively.

[0045] (Four) The concrete anti-sulfate erosion performance test: according to the national standard GB / T 50082-2009 "Standard for testing long-term performance and durability of ordinary concrete", the anti-sulfate erosion performance of the concrete of examples 1-3 and comparative example 1 is measured, the method is that before the test, the test block reaching the curing age is dried in an oven (80±5) ℃ for 48h, then cooled to room temperature, one group is put into 5% Na2SO4 solution, one group is put into clean water, the corrosion resistance coefficient of the concrete compressive strength is used to characterize the anti-sulfate erosion performance of the concrete after dry-wet cycle. The dry-wet cycle process of the concrete anti-sulfate erosion is soaking (15±0.5) h, air drying 1h, drying 6h, cooling to room temperature 2h. It is measured that the compressive strength of the concrete of example 1 can reach 118.4% of the original strength after 120 times of dry-wet cycle of anti-sulfate erosion, the compressive strength of the concrete of example 2 reaches 122.4% of the original strength after 120 times of dry-wet cycle of anti-sulfate erosion, the compressive strength of the concrete of example 3 reaches 115.4% of the original strength after 120 times of dry-wet cycle of anti-sulfate erosion, and the compressive strength of the concrete of comparative example 1 is only 94.4% of the original strength after 120 times of dry-wet cycle of anti-sulfate erosion.

[0046] (Five) Micro-morphology characterization: Figure 1 , 2 The micro-morphology diagram of the concrete of example 1 is shown in the figure, Figure 1 , 2 It can be seen that the silica ash micro-fiber is compounded with silica ash, the addition of silica ash will increase the hydration reaction rate due to its high pozzolanicity, the hydration product increases, part of the silica ash micro-fiber will be wrapped and covered by C-S-H, so as to form a more dense microstructure, Figure 1 , 2 It is shown that the silica ash micro-fiber has size effect and filler effect, which can improve the interface transition zone and fill the pores; Figure 3 , 4 The micro-morphology diagram of the concrete of example 2 is shown in the figure, Figure 3 , 4 It is shown that the WF has a connecting effect, which is wrapped by the hydration product to form a dense structure and prevent the generation of micro-cracks, and the uniformly graded WF is arranged in a more ordered way, Figure 3 , 4 It is illustrated that the replacement of part of the cement with silica ash micro-fiber can make the pores in the concrete discontinuous and more dense.

[0047] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A wollastonite microfiber composite mineral admixture reinforced concrete, characterized by, The concrete is prepared from a wollastonite microfiber modified mineral admixture, a redispersible latex powder, a water reducing agent, cement and aggregates; the wollastonite microfiber modified mineral admixture comprises wollastonite microfibers and silica fume; The wollastonite microfibers replace 5-20% of the cement by equal amount, the silica fume replaces 3-9% of the cement by equal amount, the polypropylene fiber is used in an amount of 0.05-0.2% of the cementitious materials, and the sodium silicate is used in an amount of 5.5-7% of the cementitious materials, based on 100% of the cement quality; The cementitious materials comprise cement and silica fume; The water-cement ratio is 0.45-0.

6.

2. The concrete according to claim 1, characterized in that The wollastonite microfibers replace 5% of the cement by equal amount, the silica fume replaces 5% of the cement by equal amount, and the water reducing agent is used in an amount of 0.5% of the cementitious materials, based on 100% of the cement quality.

3. A method of producing the concrete according to claim 1 or 2, characterized in that, The method comprises the following steps: (1) uniformly stirring wollastonite microfibers, silica fume, a redispersible latex powder and cement in a concrete mixer to obtain mixed dry materials 1; (2) adding fine aggregates and coarse aggregates to the mixed dry materials 1 and continuing to stir to obtain mixed dry materials 2; (3) dissolving a water reducing agent in water to prepare a water reducing agent solution, pouring the water reducing agent solution into the mixed dry materials 2 and stirring to obtain a slurry; (4) pouring the slurry into a mold, placing it for 24 hours and then curing in a standard curing environment to obtain the concrete.

4. A wollastonite microfiber composite mineral admixture reinforced concrete, characterized by, The concrete is prepared from a wollastonite microfiber modified mineral admixture, a polypropylene fiber, cement and aggregates; The wollastonite microfiber modified mineral admixture comprises wollastonite microfibers and silica fume; The wollastonite microfibers replace 5-20% of the cement by equal amount, the silica fume replaces 3-9% of the cement by equal amount, the polypropylene fiber is used in an amount of 0.05-0.2% of the cementitious materials, and the sodium silicate is used in an amount of 5.5-7% of the cementitious materials, based on 100% of the cement quality; The cementitious materials comprise cement and silica fume; The water-cement ratio is 0.45-0.

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5. The concrete according to claim 4, characterized in that The wollastonite microfibers replace 10% of the cement by equal amount, the silica fume replaces 7% of the cement by equal amount, the polypropylene fiber is used in an amount of 0.2% of the cementitious materials, and the water-cement ratio is 0.45, based on 100% of the cement quality.

6. A method of producing the concrete according to claim 4 or 5, characterized in that, The preparation method comprises the following steps: (1) uniformly stirring wollastonite microfibers, silica fume, a polypropylene fiber and cement in a concrete mixer to obtain mixed dry materials 1; (2) adding fine aggregates and coarse aggregates to the mixed dry materials 1 and continuing to stir to obtain mixed dry materials 2; (3) pouring water into the mixed dry materials 2 and stirring to obtain a slurry; (4) pouring the slurry into a mold, placing it for 24 hours and then curing in a standard curing environment to obtain the concrete.

7. A wollastonite microfiber composite mineral admixture reinforced concrete, characterized by, The concrete is prepared from a wollastonite microfiber modified mineral admixture, a polypropylene fiber, sodium silicate, cement and aggregates; The wollastonite microfiber modified mineral admixture comprises wollastonite microfibers and granulated blast furnace slag powder; The wollastonite microfibers replace 5-20% of the cement by equal amount, the granulated blast furnace slag powder replaces 65-80% of the cement by equal amount, the polypropylene fiber is used in an amount of 0.05-0.2% of the cementitious materials, and the sodium silicate is used in an amount of 5.5-7% of the cementitious materials, based on 100% of the cement quality; The cementitious materials comprise cement and granulated blast furnace slag powder; The water-cement ratio is 0.45-0.

6.

8. A method of producing the concrete according to claim 7, characterized by, The preparation method comprises the following steps: (1) uniformly stir wollastonite microfiber, granulated blast furnace slag powder, polypropylene fiber and cement in a concrete mixer to obtain mixed dry material 1; (2) continue to stir the fine aggregate and coarse aggregate into the mixed dry material 1 to obtain mixed dry material 2; (3) dissolve sodium silicate in water to obtain a sodium silicate solution, and pour the sodium silicate solution into the mixed dry material 2 to obtain a slurry; (4) pour the slurry into a mold, place it for 24 hours, and then cure it in a standard curing environment to obtain concrete.

9. The production method according to claim 3, 6 or 8, characterized by, The stirring time in (2) is 30 seconds.

10. The method of making according to claim 3, 6 or 8, wherein, The stirring time in (3) is 2 minutes.

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