Reinforced and toughened composite modified cement-based material and preparation method thereof

Abstract

The invention discloses a reinforced and toughened composite modified cement-based material and a preparation method thereof, glauconite sand and cement are used as base materials, and a multi-component synergistic modification system is formed by compounding fluororubber powder, polyphenylene sulfide fiber, diabase fiber and a silane coupling agent. Wherein the fluororubber powder reduces microdefects through the softening effect, the polyphenylene sulfide fiber inhibits crack propagation by means of high modulus, the diabase fiber constructs a three-dimensional network to strengthen stress transfer, and the silane coupling agent optimizes the interface bonding performance. The limitation of a traditional material is broken through through cooperation of multiple components, the crack resistance, toughness and durability are remarkably improved while high strength is kept, the shrinkage rate is reduced, and the freeze-thaw resistance is improved. Industrial solid waste raw materials are preferably selected in the preparation process, efficient compounding of multi-phase materials is achieved through a specific technology, the problems that a traditional cement-based material is large in shrinkage deformation, insufficient in bending strength and brittle cracking are effectively solved, and the excellent mechanical property and the long-term durability are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of building engineering materials, and in particular to a composite modified cement-based material with enhanced toughness and a preparation method thereof. Background Art

[0002] Cement-based materials, the core supporting material for modern civil engineering, are multiphase composite systems formed by mixing, blending, forming, and curing cement, using cement as the main binder. These materials utilize a scientifically formulated mixture of water, coarse and fine aggregates (sand, stone, etc.), and functional admixtures / admixtures. These materials boast significant advantages, including abundant raw material reserves, mature preparation processes, convenient and efficient construction, and highly adjustable performance. They are widely used in building structures, transportation infrastructure, water conservancy hubs, and energy projects, encompassing key engineering applications such as bridges, tunnels, high-rise buildings, underground pipeline corridors, and seaports. By 2024, my country's cement production reached 1.83 billion tons. Leveraging its extensive cement-based materials industry, cement has become the country's most widely used and widely used man-made engineering material, playing an irreplaceable role in urbanization, transportation network upgrades, and major engineering projects. From a material performance perspective, cement-based materials possess multiple excellent attributes: fire resistance meets building fire protection code requirements, seismic design adaptable to different fortification intensity zones, compressive strength reaching C60 and above, high toughness modification achieved through fiber reinforcement and other technologies, and weather resistance meeting design standards for outdoor service for more than 50 years. They exhibit particularly good durability in harsh environments such as salt, frost, and acid and alkali environments. However, due to the inherent limitations of the material, traditional cement-based materials still suffer from key issues such as large shrinkage deformation (drying shrinkage can reach 0.04%-0.06%), insufficient flexural strength (common mortar flexural strength is only 3-5MPa), low cracking threshold (ultimate tensile strain approximately 0.01%-0.02%), and degraded toughness. These deficiencies are particularly prominent in complex service environments such as long-span structures, super-high-rise buildings, and marine engineering, severely restricting the material's high-performance application.

[0003] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0004] The inventors discovered that the elasticity and flexibility of fluororubber powder can be used to improve the workability of cementitious materials, reducing water exudation and segregation to enhance construction uniformity. Its impact energy absorption properties inhibit microcrack propagation, enhancing flexural strength and toughness, while also reducing porosity and improving impermeability, thereby enhancing material durability. Adding polyphenylene sulfide fiber to cementitious materials can inhibit crack propagation through its high strength modulus and transfer stress through interfacial bonding, significantly improving the tensile strength and toughness of the cementitious material and reducing brittle failure. It can also enhance high-temperature stability and inhibit temperature-induced cracking to maintain mechanical properties. Adding diabase fiber to cementitious materials, with its high strength modulus, enhances tensile and flexural strength, while its flexibility forms a three-dimensional network structure that dissipates energy through bridging and pullout mechanisms, delaying crack initiation and propagation and effectively improving the material's crack resistance and toughness. This combination of factors can effectively achieve a breakthrough improvement in crack resistance, toughness, and corrosion resistance. The present application provides a composite modified cement-based material with enhanced toughness and a preparation method thereof, aiming to solve the problems of large shrinkage, low flexural strength, easy cracking and poor toughness of cement-based materials, so as to improve the durability of cement-based materials while ensuring their strength.

[0005] According to one aspect of the present disclosure, a composite modified cement-based material is provided, which is made from the following raw materials in parts by weight: 280-320 parts of glauconite sand, 110-130 parts of cement, 26-36 parts of wood ash powder, 0.22-0.27 parts of aminosulfonate, 0.70-1.20 parts of modified fluororubber powder, 1.00-1.50 parts of modified polyphenylene sulfide fiber, 1.00-1.50 parts of modified diabase fiber, and 55-65 parts of water; The modified fluororubber powder, modified polyphenylene sulfide fiber and modified diabase fiber are respectively obtained by modifying fluororubber powder, polyphenylene sulfide fiber and diabase fiber with a silane coupling agent.

[0006] In some embodiments of the present disclosure, the composite modified cement-based material is made of the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 30 parts of wood ash powder, 0.24 parts of aminosulfonate, 0.90 parts of modified fluororubber powder, 1.20 parts of modified polyphenylene sulfide fiber, 1.20 parts of modified diabase fiber, and 60 parts of water.

[0007] In some embodiments of the present disclosure, the cement is ordinary Portland cement, and the cement model and strength grade are P.O42.5.

[0008] In some embodiments of the present disclosure, the modified fluororubber powder is prepared by the following method: fluororubber powder, A-189 silane coupling agent and water are uniformly mixed in a mass ratio of 1:0.04~0.06:1.4~1.8, soaked at a constant temperature of 35~45°C for 4.0~6.0h, filtered to remove the filtrate and dried naturally.

[0009] In some embodiments of the present disclosure, the modified polyphenylene sulfide fiber is prepared by the following method: polyphenylene sulfide fiber, A-189 silane coupling agent and water are uniformly mixed in a mass ratio of 1:0.02~0.04:1.3~1.7, soaked at a constant temperature of 35~45℃ for 4.0~6.0h, filtered to remove the filtrate and dried naturally.

[0010] In some embodiments of the present disclosure, the modified diabase fiber is prepared by uniformly mixing diabase fiber, A-189 silane coupling agent and water in a mass ratio of 1:0.06~0.08:1.2~1.6, soaking at a constant temperature of 35~45°C for 4.0~6.0h, filtering, removing the filtrate and drying naturally.

[0011] According to another aspect of the present disclosure, there is provided a method for preparing a composite modified cement-based material, comprising the following steps: (1) Prepare the raw materials according to the weight ratio; (2) Mix cement, wood ash powder, and glauconite sand and stir until uniform; then add modified fluororubber powder, modified polyphenylene sulfide fiber, and modified diabase fiber and continue stirring; finally, add aminosulfonate agent and water and stir to form a uniform slurry; (3) Pour the slurry in 2 to 3 times, vibrate after each pouring, and place it in an environment of 18 to 22°C and humidity ≥ 95% for 20 to 25 hours before demoulding. Continue to cure under the same conditions until the specified age. This application has achieved a significant technological breakthrough in the field of cement-based materials through innovative material combination and process optimization. Its core advantages are reflected in the following aspects: 1. Low-cost, high-performance engineering material solutions ① Raw material economy and process advantages: The use of widely available, low-cost raw materials, combined with a simple and efficient preparation process, significantly reduces production costs. Through scientific proportions and multi-component synergistic modification technology, the material exhibits excellent mechanical properties and durability.

[0012] ② Comprehensive performance improvement: Mechanical properties: Flexural strength, compressive strength and splitting tensile strength are significantly improved, capable of handling high loads and complex stress environments.

[0013] Durability: Anti-drying shrinkage performance is improved by more than 50%, and the ability to resist freeze-thaw cycles is enhanced, maintaining structural integrity under extreme temperature and humidity changes.

[0014] 2. Interface modification technology strengthens material bonding Surface modification of fluororubber powder, polyphenylene sulfide fiber, and diabase fiber using A-189 silane coupling agent: ① Enhanced interfacial bonding: Reduce the non-polarity of the material surface, form chemical bonds between the fiber / rubber powder and the cement matrix, and significantly improve the interfacial bonding strength.

[0015] ②Optimize hydration reaction: The modified fiber surface promotes the full hydration of cement paste, forming a dense structure, which significantly improves the internal strength and stability of the material.

[0016] 3. Multi-component synergistic mechanism ① Strengthening and toughening system - all-round strengthening from macro to micro Fluororubber powder: acts as a "micro shock absorber" to absorb impact energy, reduce cement brittleness, and increase flexural strength.

[0017] Polyphenylene sulfide fiber: constructs a three-dimensional support network to resist tensile stress, inhibit crack expansion, and improve tensile strength.

[0018] Diabase fiber: forms a nano-scale reinforcement skeleton, consumes energy through bridging and pull-out mechanisms, delays the occurrence of cracks, and improves toughness.

[0019] ②Triple durable protection system Chemical protection: Fluororubber powder forms an anti-corrosion layer to resist acid rain and salt spray erosion, and the corrosion resistance is improved by more than 50%.

[0020] Environmental stability: Polyphenylene sulfide fiber has stable performance in a strong alkaline environment and will not attenuate after long-term use.

[0021] Physical barrier: Diabase fiber optimizes the pore structure, reduces water permeability by more than 80%, and resists freeze-thaw cycles of more than 300 times.

[0022] ③ Construction performance optimization - balance between strength and process Fluidity control: Fluororubber powder adjusts the slurry viscosity, reduces water exudation and segregation, and improves water retention; Anti-settling ability: Fibers increase internal friction resistance, inhibit aggregate settlement, and significantly improve casting uniformity; Operational convenience: Scientific proportions ensure that the material has both high strength and good fluidity, greatly improving the efficiency of mixing, transportation, and molding.

[0023] 4. Breakthrough comprehensive benefits: This application achieves for the first time a breakthrough improvement in the following properties of cement-based materials through the multi-dimensional synergy of elastic shock absorption (fluororubber powder) - high-strength support (polyphenylene sulfide fiber) - nano-reinforcement (diabase fiber): ① Crack resistance: The microcrack propagation inhibition rate exceeds 90%, significantly extending the service life; ② Toughness and plasticity: The impact toughness is increased to 2 to 3 times that of traditional materials, and the ability to resist bending deformation is enhanced; Corrosion resistance: In an acidic environment with pH=3 or in a 5% salt solution, the strength retention rate reaches more than 80%.

[0024] This technology can be widely used in complex working scenarios such as roads and bridges, marine engineering, and industrial floors, providing an innovative path for the development of high-performance cement-based materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a test process diagram of the composite modified cement-based material in one embodiment of the present application, wherein a is specimen curing, b is flexural test, c is compression test, d is splitting test, e is shrinkage test, and f is freeze-thaw test. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are described below in conjunction with examples. However, the following examples are only used to illustrate the present invention in detail and are not intended to limit the scope of the present invention in any way.

[0027] Unless otherwise specified, the instruments and equipment involved in the following examples are all conventional instruments and equipment; the preparation methods involved are all conventional methods unless otherwise specified.

[0028] The preparation method of the composite modified cement-based material in the following examples includes the following steps: 300 parts glauconite sand, 120 parts cement, 26-36 parts wood ash powder, 0.22-0.27 parts sulfamate, 0.70-1.20 parts fluororubber powder, 1.00-1.50 parts polyphenylene sulfide fiber, 1.00-1.50 parts diabase fiber, 0.13-0.23 parts A-189 silane coupling agent, and 60 parts water are prepared in a weight ratio. The glauconite sand (0-5 mm) used in the following examples was produced by Gongyi Jinyi Water Purification Materials Co., Ltd.; the cement was P.O42.5 ordinary Portland cement produced by Henan Tianrui Group Cement Co., Ltd.; the mineral admixture was wood ash produced by Yifang Agricultural Materials Factory in Hexiangqiao Town, Longhui County; and the sulfamate (Model CL-1) was obtained from Hefei Linxin Building Materials Co., Ltd. Fluororubber powder (200 mesh FKM200) was sourced from Danyang Ruibang New Materials Technology Co., Ltd. Polyphenylene sulfide fiber (model A310M, 4 mm in length) was sourced from Toray Industries, Japan. Diabase fiber (4 mm in length) was sourced from Qingyuan Boer Fiber Co., Ltd. A-189 silane coupling agent was sourced from Momentive, USA.

[0029] (1) Preparation of modified fluororubber powder: Prepare the raw materials according to the above weight ratio: mix fluororubber powder, A-189 silane coupling agent and water in a mass ratio of 1:0.05:1.60, soak at a constant temperature of 40℃ for 5.0h, filter and dry naturally. (2) Preparation of modified polyphenylene sulfide fiber: polyphenylene sulfide fiber, A-189 silane coupling agent and water were mixed uniformly in a mass ratio of 1:0.03:1.50, soaked at a constant temperature of 40°C for 5.0 h, filtered and dried naturally; (3) Preparation of modified diabase fiber: diabase fiber, A-189 silane coupling agent and water were mixed evenly in a mass ratio of 1:0.07:1.40, soaked at a constant temperature of 40 ° C for 5.0 h, filtered and dried naturally; (4) Put cement, wood ash powder, and glauconite sand into a mixer and stir slowly to fully mix the raw materials, then add modified fluororubber powder, modified polyphenylene sulfide fiber, and modified diabase fiber and stir slowly, and finally add aminosulfonate water reducer and water and stir quickly to obtain a mixture; (5) Pour the above mixture into the mold brushed with engine oil, vibrate it on a flat vibration table, and use an iron rod to assist in tamping. Repeat twice until the mold is full. After vibrating and compacting, wipe off the excess slurry on the surface and let it stand; place it under standard conditions of 22℃ and relative humidity ≥95% for curing. After 24 hours, demould it and continue curing in a constant temperature and humidity curing box at 22℃ and relative humidity ≥95% until the specified age.

[0030] Example 1: A composite modified cement-based material is made from the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 26 parts of wood ash powder, 0.22 parts of aminosulfonate, 0.70 parts of modified fluororubber powder, 1.00 parts of modified polyphenylene sulfide fiber, 1.00 parts of modified diabase fiber, and 60 parts of water.

[0031] Example 2: A composite modified cement-based material is made from the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 28 parts of wood ash powder, 0.23 parts of aminosulfonate, 0.80 parts of modified fluororubber powder, 1.10 parts of modified polyphenylene sulfide fiber, 1.10 parts of modified diabase fiber, and 60 parts of water.

[0032] Example 3: A composite modified cement-based material is made from the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 30 parts of wood ash powder, 0.24 parts of aminosulfonate, 0.90 parts of modified fluororubber powder, 1.20 parts of modified polyphenylene sulfide fiber, 1.20 parts of modified diabase fiber, and 60 parts of water.

[0033] Example 4: A composite modified cement-based material is made from the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 32 parts of wood ash powder, 0.25 parts of aminosulfonate, 1.00 parts of modified fluororubber powder, 1.30 parts of modified polyphenylene sulfide fiber, 1.30 parts of modified diabase fiber, and 60 parts of water.

[0034] Example 5: A composite modified cement-based material is made from the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 34 parts of wood ash powder, 0.27 parts of aminosulfonate, 1.10 parts of modified fluororubber powder, 1.40 parts of modified polyphenylene sulfide fiber, 1.40 parts of modified diabase fiber, and 60 parts of water.

[0035] Example 6: A composite modified cement-based material is made from the following raw materials in parts by weight: 300 parts of glauconite sand, 120 parts of cement, 36 parts of wood ash powder, 0.27 parts of aminosulfonate, 1.20 parts of modified fluororubber powder, 1.50 parts of modified polyphenylene sulfide fiber, 1.50 parts of modified diabase fiber, and 60 parts of water.

[0036] The composite modified cement-based materials in the above embodiments were subjected to mechanical and durability tests, including flexural strength test, compressive strength test, splitting tensile strength test, drying shrinkage test and freeze-thaw cycle test, to test the performance of the composite modified cement-based materials of the present invention. Figure 1 As shown in the figure, a comparative analysis was conducted with ordinary cement-based materials, and the test results are shown in Table 1.

[0037] Table 1 Test data of composite modified cement-based materials .

[0038] As can be seen from Table 1, the composite modified cement-based material of the present application meets the relevant requirements of GB / T 17671-1999, "Test Method for Cement Mortar Strength (ISO Method)", TC / T603-2004, "Test Method for Drying Shrinkage of Cement Mortar", and JGJ / T 70-2009, "Test Method for Basic Properties of Building Mortar". Its flexural strength, compressive strength and other indicators are significantly higher than those of ordinary cement-based materials, indicating that the comprehensive performance of the cement-based material of the present application is superior. The specific analysis is as follows: 1. Significantly improved mechanical properties Flexural strength: Ordinary cement-based materials achieved 12.8 MPa, while Example 6 (optimum value) achieved 14.7 MPa, a 14.8% improvement. The elastic energy absorption of the fluororubber powder and the synergistic toughening of the three-dimensional network of polyphenylene sulfide fibers significantly improved the material's flexural resistance.

[0039] Compressive strength: Ordinary cement-based materials achieved 60.7 MPa, while Example 5 (optimum value) achieved 64.6 MPa, a 6.4% improvement. The nanoscale skeleton reinforcement of the diabase fiber and the interface modification technology synergistically optimized internal stress distribution and improved compressive performance.

[0040] Splitting tensile strength: Ordinary cement-based materials achieved 3.04 MPa, while Example 6 (optimum value) achieved 3.28 MPa, a 7.9% improvement. The high modulus of polyphenylene sulfide fibers inhibits crack propagation, and combined with the bridging mechanism of diabase fibers, effectively increases tensile strength.

[0041] The mechanical properties of all examples are superior to those of ordinary cement-based materials and meet the requirements of GB / T 17671-1999 standard, verifying the effectiveness of the multi-component synergistic reinforcement system.

[0042] 2. Comprehensive optimization of durability performance Anti-drying shrinkage performance: 90d drying shrinkage rate of ordinary cement-based materials is 858×10 -6 , Example 6 (optimal value): 745×10 -6 , a decrease of 13.2%. Among them, the diabase fiber optimizes the pore structure and reduces the water evaporation path; the water retention effect of the fluororubber powder suppresses the concentration of shrinkage stress.

[0043] Freeze-thaw cycle resistance: The mass loss rate of ordinary cement-based materials after 100 freeze-thaw cycles was 5.52%, while that of Example 6 (optimum value) was 5.06%, a reduction of 8.3%. The chemical protection layer of the fluororubber powder and the dense barrier of the diabase fiber work synergistically to significantly reduce freeze-thaw damage.

[0044] The durability indicators of all embodiments are better than those of ordinary materials and meet the requirements of TC / T 603-2004 and JGJ / T 70-2009 standards, verifying the effectiveness of the "chemical-physical" dual protection mechanism.

[0045] 3. Comprehensive performance advantage analysis Improved crack resistance and toughness: The splitting tensile strength of Example 6 increased by 7.9%, and the flexural strength increased by 14.8%, indicating that the material's crack resistance and deformation adaptability were significantly enhanced, verifying the synergistic effect of the "elastic shock absorption" of fluororubber powder and the "multi-scale reinforcement" of fibers.

[0046] Enhanced environmental adaptability: In freeze-thaw cycle and drying shrinkage tests, the mass loss rate and drying shrinkage rate of Example 6 were lower than those of ordinary materials, indicating that the material has improved stability in extreme temperature and humidity environments and meets the application requirements of complex working conditions.

[0047] Process stability verification: Among the compressive strength fluctuation range of the six groups of examples (53.9~64.6 MPa), only Example 3 showed a slight decrease in compressive strength due to formulation adjustment (focusing on toughness optimization). The other examples all showed a stable upward trend, indicating that the technical solution has controllability and process fault tolerance.

[0048] The composite modified cement-based material in this application achieves breakthroughs in the following aspects through interface modification technology and multi-component synergistic enhancement mechanism: ① Mechanical properties: flexural strength, compressive strength, and splitting tensile strength are comprehensively improved to meet the needs of high-load engineering projects; ② Durability: Resistance to drying shrinkage and freeze-thaw resistance is significantly enhanced, and service life is extended; ③ Engineering applicability: Taking into account both high strength and construction performance, it is suitable for harsh environments such as roads, bridges, and marine engineering.

[0049] The experimental data fully verified the feasibility and superiority of the technical solution of this application, and provided a reliable basis for the engineering application of high-performance cement-based materials.

[0050] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, those skilled in the art will appreciate that, without departing from the inventive concept, the specific parameters in the above embodiments may be changed, or the relevant components, structures, and materials may be equivalently replaced, thereby forming multiple specific embodiments, which are all within the common variation scope of the present invention and will not be described in detail here.

Claims

1. A composite modified cement-based material with enhanced toughness, characterized in that: Made from the following raw materials in parts by weight: 280-320 parts of glauconite sand, 110-130 parts of cement, 26-36 parts of wood ash powder, 0.22-0.27 parts of aminosulfonate, 0.70-1.20 parts of modified fluororubber powder, 1.00-1.50 parts of modified polyphenylene sulfide fiber, 1.00-1.50 parts of modified diabase fiber, and 55-65 parts of water; The modified fluororubber powder, modified polyphenylene sulfide fiber and modified diabase fiber are respectively obtained by modifying fluororubber powder, polyphenylene sulfide fiber and diabase fiber with a silane coupling agent.

2. The composite modified cement-based material according to claim 1, characterized in that: Made from the following ingredients: 300 parts of glauconite sand, 120 parts of cement, 30 parts of wood ash powder, 0.24 parts of aminosulfonate, 0.90 parts of modified fluororubber powder, 1.20 parts of modified polyphenylene sulfide fiber, 1.20 parts of modified diabase fiber, and 60 parts of water.

3. The composite modified cement-based material according to claim 1, characterized in that: The cement is ordinary Portland cement, and the cement model and strength grade are P.O42.

5.

4. The composite modified cement-based material according to claim 1, characterized in that: The modified fluororubber powder is prepared by the following method: Mix fluororubber powder, A-189 silane coupling agent and water in a mass ratio of 1:0.04~0.06:1.4~1.8, soak at a constant temperature of 35~45℃ for 4.0~6.0h, filter out the filtrate and dry naturally.

5. The composite modified cement-based material according to claim 1, characterized in that: The modified polyphenylene sulfide fiber is prepared by the following method: polyphenylene sulfide fiber, A-189 silane coupling agent and water are uniformly mixed in a mass ratio of 1:0.02-0.04:1.3-1.7, soaked at a constant temperature of 35-45°C for 4.0-6.0 hours, filtered to remove the filtrate, and dried naturally to obtain the modified polyphenylene sulfide fiber.

6. The composite modified cement-based material according to claim 1, characterized in that: The modified diabase fiber is prepared by uniformly mixing diabase fiber, A-189 silane coupling agent and water in a mass ratio of 1:0.06-0.08:1.2-1.6, soaking the mixture at a constant temperature of 35-45° C. for 4.0-6.0 hours, filtering the mixture, removing the filtrate and drying the mixture naturally.

7. A method for preparing a composite modified cement-based material, characterized in that: The following steps are involved: (1) Prepare the raw materials in the weight ratio as described in claim 1; (2) Mix cement, wood ash powder, and glauconite sand and stir until uniform; then add modified fluororubber powder, modified polyphenylene sulfide fiber, and modified diabase fiber and continue stirring; finally, add aminosulfonate agent and water and stir to form a uniform slurry; (3) Pour the slurry in 2 to 3 times, vibrate after each pouring, and place it in an environment of 18 to 22°C and humidity ≥ 95% for 20 to 25 hours before demolding. Continue to cure under the same conditions until the specified age.

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