Anti-fracture building concrete material and preparation method thereof

Abstract

The invention discloses an anti-fracture building concrete material and a preparation method thereof, and relates to the technical field of building materials, the concrete material comprises the following raw materials by weight: 280-380 parts of cement; 500 to 600 parts of fine aggregate; 800 to 1000 parts of coarse aggregate; 1.5 to 3.5 parts of a degradable fiber inclusion; 20 to 40 parts of silica fume; 15 to 30 parts of rice hull ash; 10 to 20 parts of modified natural zeolite; 5-10 parts of an intelligent phase change material; 3-5 parts of a polycarboxylic acid water reducer; 5 to 10 parts of a calcium sulphoaluminate expanding agent; 150 to 200 parts of water; through the elaborately designed material formula, the anti-fracture performance and durability of the concrete are remarkably improved, the introduced degradable fiber inclusion is prepared by wrapping aramid fibers with a starch-based degradable material, and the structure enhances the interface bonding force between the fibers and a concrete matrix and also improves the durability of the concrete. The expansion of microcracks in the concrete is effectively inhibited through the high-strength characteristic of the aramid fibers, and the tensile strength and toughness of the concrete are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular to a kind of anti-fracture building concrete material and preparation method thereof. BACKGROUND

[0002] With the acceleration of urbanization process and the continuous expansion of infrastructure construction, as one of the most important building materials, the performance requirements of concrete are increasingly improved, especially in high-rise buildings, large-span bridges, complex underground structure engineering, higher requirements are put forward for the anti-fracture performance, durability and intelligent level of concrete. When traditional concrete materials face the challenges of complex stress environment, temperature change and chemical erosion, they often show easy cracking and poor durability, which not only affects the service life of the building, but also may pose a threat to the safety of the structure. Therefore, developing a new type of concrete material with excellent anti-fracture performance, high durability and intelligent characteristics has become a research hotspot in the field of building materials.

[0003] Traditional concrete materials have significant shortcomings in anti-fracture performance, durability and intelligence. First, the fiber materials used in traditional concrete are mostly ordinary fibers, which have limited reinforcing effect and are difficult to effectively inhibit the expansion of internal micro-cracks in concrete, leading to easy cracking of concrete under stress. Second, the pore structure of traditional concrete materials is not optimized, and the density is low, which is easily eroded by harmful substances, thereby affecting its durability. In addition, traditional concrete materials lack intelligent characteristics and cannot automatically adjust their performance according to environmental changes, making it difficult to adapt to complex and variable engineering environments. Therefore, traditional concrete materials have been difficult to meet the demand for high-performance, long-life and intelligent building materials in modern construction engineering.

[0004] Therefore, the development of an anti-fracture building concrete material and its preparation method not only optimizes the pore structure of concrete and improves the density, but also promotes the intelligentization and environmentalization process of building materials. SUMMARY

[0005] The purpose of the present application is to make up for the shortcomings of the prior art and provide an anti-fracture building concrete material and its preparation method. The present application introduces degradable fiber wrapping body, rice husk ash, modified natural zeolite and intelligent phase change material new components, which significantly improves the anti-fracture performance, durability and intelligent level of concrete. The degradable fiber wrapping body enhances the adhesion between the fiber and the matrix, and the intelligent phase change material realizes automatic temperature adjustment.

[0006] To solve the above technical problems, the present application provides the following technical solutions: on the one hand, an anti-fracture building concrete material, the concrete material comprises the following raw materials by weight: Cement: 280-380 parts; Fine aggregate: 500-600 parts; Coarse aggregate: 800-1000 parts; Degradable fiber package: 1.5-3.5 parts; Silica ash: 20-40 parts; Rice husk ash: 15-30 parts; Modified natural zeolite: 10-20 parts; Intelligent phase change material: 5-10 parts; Polycarboxylic acid type water reducing agent: 3-5 parts; Calcium sulphoaluminate type expanding agent: 5-10 parts; Water: 150-200 parts.

[0007] Further, the degradable fiber package is prepared by wrapping aramid fiber with starch-based degradable material, and the thickness of the wrapping layer is controlled to be 5-8 μm.

[0008] Further, the aramid fiber is a core material, and the diameter is 10-15 μm.

[0009] Further, the starch-based degradable material includes 70-80 parts of starch, 10-15 parts of polybutylene adipate-co-terephthalate (PBAT), and 5-10 parts of plasticizer by weight, and the plasticizer is one of glycerol or sorbitol or a mixture of glycerol and sorbitol in a weight ratio of 1:1.

[0010] Further, the preparation method of the rice husk ash is as follows: the rice husk is calcined at a temperature of 600-800℃ in a nitrogen atmosphere containing 5-10% oxygen for 2-3 hours, and then ground to pass through a 200 mesh sieve by air flow grinding.

[0011] Further, the preparation method of the modified natural zeolite is as follows: the natural zeolite is crushed to a particle size of ≤2 mm and sieved, then soaked in a 5% silane coupling agent KH-550 ethanol solution at a solid-liquid ratio of 1:5 at 60℃ for 2 hours, and then dried at 80℃ for 4 hours, and finally ground to a D50 particle size of 10-15 μm to obtain modified natural zeolite with a specific surface area of ≥800 m 2 / g.

[0012] Further, the intelligent phase change material is melamine resin microcapsule encapsulated n-octadecane, the microcapsule particle size is 50-100 μm, the wall thickness is 1-3 μm, the phase change temperature is 20-25℃, and the phase change latent heat is 150-200 J / g.

[0013] In another aspect, a preparation method of a fracture-resistant building concrete material is provided, and the specific steps of the preparation method are as follows: S100, raw material pretreatment: rice husk is calcined at 600-800 DEG C for 2-3h, and is ground to pass through a 200 mesh screen to obtain rice husk ash; natural zeolite is crushed and sieved, then soaked in 5% silane coupling agent ethanol solution for 2h, and dried for use; after the starch-based degradable material is heated and melted, it uniformly wraps aramid fiber to obtain a fiber wrapping body; S200, dry material mixing: cement, fine aggregate, coarse aggregate, silica fume, rice husk ash and expanding agent are added to a forced mixer according to the ratio, and are dry mixed at 60-80 rpm for 1-2 minutes, then the degradable fiber wrapping body and modified zeolite are added and stirred at 100-120 rpm for 2-3 minutes until the fibers are uniformly dispersed; S300, phase change material treatment: the intelligent phase change material is heated and melted at 40-60 DEG C, and is dissolved in water together with the polycarboxylic acid-based superplasticizer to prepare a mixed solution; S400, wet material mixing: the mixed solution is slowly added to the mixer under stirring within 1-2 minutes, and is stirred at 100-120 rpm for 4-6 minutes until the slurry is uniform, to obtain the anti-cracking concrete.

[0014] Further, the S300, phase change material treatment requires that the temperature of the mixed solution be maintained at 30-50 DEG C Compared with the prior art, the anti-cracking building concrete material and the preparation method thereof have the following beneficial effects: One, the present application significantly improves the anti-cracking performance and durability of concrete by carefully designing the material formula, the introduced degradable fiber wrapping body is made of starch-based degradable material wrapping aramid fiber, this structure not only enhances the interfacial adhesion between the fiber and the concrete matrix, but also effectively inhibits the expansion of the internal micro-cracks of the concrete through the high strength characteristics of the aramid fiber, improves the tensile strength and toughness of the concrete, at the same time, the starch-based degradable material gradually degrades after the concrete hardens, leaving a porous structure, which helps to relieve the stress concentration inside the concrete, further reducing the generation of cracks, in addition, the addition of rice husk and modified natural zeolite optimizes the pore structure of the concrete through the micro aggregate filling effect and the pozzolanic activity reaction, improves the compactness, effectively prevents the invasion of harmful substances, and prolongs the service life of the concrete.

[0015] Secondly, the application has the ability to automatically adjust the temperature by adding intelligent phase change materials such as melamine resin microcapsule encapsulated n-octadecane, which can absorb or release heat when the temperature changes, effectively alleviating the problem of concrete cracking caused by temperature stress, improving the thermal comfort and energy efficiency of buildings, at the same time, the microcapsule structure of intelligent phase change materials ensures its stability and durability in concrete, prolonging its service life, in the aspect of environmental protection, the application uses rice husk ash, modified natural zeolite industrial by-products and natural minerals, not only reduces the use amount of high energy consumption materials, but also realizes the resource utilization of waste, reduces the production cost and relieves the environmental pressure.

[0016] Other advantages, objects, and features of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0018] Figure 1 A flowchart of a preparation method of a fracture-proof building concrete material. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific embodiments, structures, features and effects according to the present application will be described in detail below with reference to the drawings and preferred embodiments.

[0020] Embodiment one: An application example of the fracture-proof building concrete in high-rise building floor.

[0021] A new 30-story commercial complex is built in the core area of a city, the standard floor span is 8m x 8m, and the design load is 3.5kN / m 2 Due to the significant influence of temperature change, structure settlement and dynamic load on high-rise buildings, the traditional concrete floor is prone to through cracks, which affects the safety and use function of the structure. Therefore, the fracture-proof building concrete material of the present application is selected for floor pouring to improve the crack resistance and durability.

[0022] Material proportioning design (by weight parts): cement 320 parts, P.O 42.5 grade ordinary portland cement is selected; fine aggregate 550 parts, river sand with fineness modulus of 2.6 and clay content <1%; coarse aggregate 900 parts, 5-25 mm continuous gradation gravel with crushing value <10%; degradable fiber package 2.5 parts, made of starch-based material wrapping aramid fiber, wrapping layer thickness 6 μm, aramid fiber diameter 12 μm; silica fume 30 parts, specific surface area ≥15000 m 2 / g, SiO2content >92%; rice husk ash 20 parts, calcined at 600℃ for 2.5h in nitrogen atmosphere with oxygen content of 8%, sieved through 200 mesh; modified natural zeolite 15 parts, modified by silane coupling agent KH-550, specific surface area 850 m 2 / g, D50 particle size 12 μm; intelligent phase change material 8 parts, microcapsule encapsulated n-octadecane with melamine resin, particle size 80 μm, phase change temperature 22℃, latent heat 180 J / g; polycarboxylic acid type water reducing agent 4 parts, water reducing rate 25%, solid content 30%; calcium sulphoaluminate type expansive agent 8 parts, limiting expansion rate ≥0.02%; water 180 parts, drinking water is used.

[0023] The detailed steps of the preparation process are as follows: Raw material pretreatment: preparation of rice husk ash: put the rice husk into a muffle furnace, calcine at 600℃ for 2.5h in a nitrogen atmosphere containing 8% oxygen. After cooling, powder through 200 mesh by air jet mill, then seal and store for later use, as shown in Figure 1 .

[0024] Preparation of modified natural zeolite: crush the natural zeolite to a particle size ≤2 mm, sieve, then soak in 5% silane coupling agent KH-550 ethanol solution (solid-liquid ratio 1:5) at 60℃ for 2h. Then dry at 80℃ for 4h, then grind to D50 particle size 12 μm.

[0025] Preparation of degradable fiber package: weigh 75 parts of starch, 12 parts of PBAT and 8 parts of glycerol, melt at 140℃, then uniformly wrap aramid fiber with diameter of 12 μm, control the wrapping layer thickness to be 6 μm. After cooling, cut into short fibers of 5-10 mm.

[0026] Dry material mixing: add 320 parts of cement, 550 parts of fine aggregate, 900 parts of coarse aggregate, 30 parts of silica fume, 20 parts of rice husk ash, and 8 parts of expansive agent into a forced mixer, dry mix at low speed of 70 rpm for 1.5 minutes.

[0027] Add 2.5 parts of degradable fiber package and 15 parts of modified zeolite, stir at high speed of 110 rpm for 2.5 minutes until the fiber is uniformly dispersed without agglomeration.

[0028] Phase change material treatment: 8 parts of intelligent phase change material were heated and melted at 50°C, mixed with 4 parts of polycarboxylic acid-based superplasticizer in 180 parts of water, and stirred uniformly. The solution temperature was maintained at 40°C to form a mixed solution.

[0029] Wet material mixing and pouring: In the state of the mixer running at 110 rpm, the mixed solution was slowly added within 1.5 minutes, and then high-speed stirring was continued for 5 minutes until the slurry was uniform, and the slump was controlled at 180±20 mm.

[0030] After the concrete was transported to the construction site, it was poured into the floor formwork using pumping method. The vibrating was performed using an inserted vibrator, and the operation was fast insertion and slow pulling to avoid over-vibration leading to fiber floating. Within 12 hours after pouring, plastic film was covered for moisture curing, and the curing period was 14 days.

[0031] Performance test and application effect: Crack resistance: 7 days after pouring, ultrasonic flaw detection was used to detect internal cracks of the floor, and no micro-cracks with a width >0.05 mm were found; at 28 days of age, no visible cracks appeared on the surface of the floor.

[0032] The tensile strength test result was 4.2 MPa, which was 50% higher than that of traditional C30 concrete (tensile strength 2.8 MPa), and the toughness index reached 25, indicating that the material's ability to resist crack propagation had been significantly enhanced.

[0033] Durability: The impermeability grade reached P12 (traditional concrete P8), and the chloride ion permeability coefficient was <1000 Coulombs, which could effectively prevent harmful substances from entering.

[0034] The pozzolanic reaction of rice husk ash and modified zeolite reduced the porosity of the concrete by 12%, increased the compactness, and the carbonation depth was only 3.5 mm at 28 days (traditional concrete 5.8 mm).

[0035] In summary, in this embodiment, the anti-cracking building concrete significantly improves the crack resistance and durability of high-rise building floors by the toughening effect of the degradable fiber wrapping body and the micro-aggregate filling effect of rice husk ash and modified zeolite. Compared with traditional concrete, this material exhibits stronger structural stability in building scenarios with large span and complex load, while reducing the maintenance cost in the later stage, meeting the needs of green building and sustainable development.

[0036] Example Two: Optimization of the amount of degradable fiber wrapping body for anti-cracking building concrete material.

[0037] To study the influence of the amount of degradable fiber package on the performance of concrete, five groups of comparative experiments were designed, except that the amount of degradable fiber package was adjusted in a gradient of 1.5-3.5 parts, the rest of the raw material ratio remained the same: cement 320 parts, fine aggregate 550 parts, coarse aggregate 900 parts, silica fume 30 parts, rice husk ash 20 parts, modified natural zeolite 15 parts, intelligent phase change material 8 parts, polycarboxylic acid type water reducing agent 4 parts, calcium sulphoaluminate type expansive agent 8 parts, water 180 parts.

[0038] The amount of degradable fiber package and preparation process of each group: Group 1: 1.5 parts of degradable fiber package, the same wrapping process as Example 1; Group 2: 2.0 parts, the same wrapping process as Example 1; Group 3: 2.5 parts, the same wrapping process as Example 1, the same wrapping process as Example 1; Group 4: 3.0 parts, the same wrapping process as Example 1; Group 5: 3.5 parts, the same wrapping process as Example 1.

[0039] Preparation steps same as Example 1: Raw material pretreatment: rice husk is calcined in a nitrogen atmosphere containing 8% oxygen at 600°C for 2.5h, ground to pass 200 mesh screen to prepare rice husk ash; natural zeolite is broken to ≤2mm, soaked in 5% silane coupling agent KH-550 ethanol solution (solid-liquid ratio 1:5) at 60°C for 2h, dried at 80°C for 4h, then ground to D50 particle size 12μm; starch-based material (75 parts of starch + 12 parts of PBAT + 8 parts of glycerol) is heated to 140°C to melt, wrapped aramid fiber and cut into 5-10mm short fibers.

[0040] Dry material mixing: mix the raw materials at a low speed of 70rpm for 1.5 minutes, add the fiber package and modified zeolite, and stir at a high speed of 110rpm for 2.5 minutes until the fiber is evenly dispersed.

[0041] Phase change material treatment: 8 parts of intelligent phase change material is melted at 50°C, and 4 parts of water reducing agent is dissolved in 180 parts of water, keeping the solution temperature at 40°C.

[0042] Wet material mixing and curing: mix the solution in 1.5 minutes, stir at a high speed of 110rpm for 5 minutes, and control the slump to 180±20mm; cover the film to keep moist and cure for 14 days within 12 hours after pouring.

[0043] Analyze the influence of degradable fiber package on the performance of concrete, and generate Table 1.

[0044]

[0045] Table 1 In summary, in the range of 1.5-3.5 parts by weight, the amount of degradable fiber wrapping has a significant effect on the crack resistance and durability of concrete. When the amount is 2.5 parts, the tensile strength is 50% higher than that of traditional concrete, the toughness index is 25, the impermeability level is P12, the porosity is reduced by 12%, and the carbonation depth is the smallest. This is because the appropriate amount of aramid fiber can effectively inhibit the expansion of microcracks, and the porous structure formed after the degradation of the starch-based wrapping can relieve stress concentration, while excessive or insufficient amount will lead to uneven dispersion of fibers or limited enhancement effect. The results verify the optimized range of the amount of degradable fiber wrapping in the formulation of the present application, providing a quantitative basis for practical engineering applications.

[0046] Example Three: Optimization of Rice Husk Ash Amount for Anti-cracking Building Concrete Material

[0047] To study the effect of rice husk ash amount on the performance of concrete, four groups of comparative experiments were designed. Except for the amount of rice husk ash, which was adjusted in a gradient of 15-30 parts, the remaining raw material ratios were kept consistent: cement 320 parts, fine aggregate 550 parts, coarse aggregate 900 parts, degradable fiber wrapping 2.5 parts, silica fume 30 parts, modified natural zeolite 15 parts, intelligent phase change material 8 parts, polycarboxylate-based superplasticizer 4 parts, calcium sulphoaluminate expansive agent 8 parts, and water 180 parts.

[0048] Amount of rice husk ash and preparation process for each group: Group 1: 15 parts of rice husk ash, preparation process same as Example One; Group 2: 20 parts, same amount as Example One, preparation process same as Example One; Group 3: 25 parts, preparation process same as Example One; Group 4: 30 parts, preparation process same as Example One.

[0049] Preparation steps same as Example One: Raw material pretreatment: rice husks were calcined and ground according to the amount; natural zeolite was broken to ≤2mm, soaked in 5% silane coupling agent KH-550 ethanol solution (solid-liquid ratio 1:5) at 60°C for 2h, dried at 80°C for 4h, and then ground to D50 particle size of 12μm; starch-based material was used to wrap aramid fibers to obtain fiber wrapping.

[0050] Dry material mixing: the raw materials were dry mixed at a low speed of 70rpm for 1.5 minutes, and then the fiber wrapping and modified zeolite were added and stirred at a high speed of 110rpm for 2.5 minutes until the fibers were evenly dispersed.

[0051] Phase change material treatment: the intelligent phase change material was melted at 50°C, dissolved with the superplasticizer in water, and the solution temperature was maintained at 40°C.

[0052] Wet material mixing and curing: the mixed solution was added to the mixer and stirred at a high speed for 5 minutes, and then poured and cured for 14 days.

[0053] The influence of rice husk ash on the performance of concrete was analyzed to generate Table 2.

[0054]

[0055] Table 2 In summary, in the range of 15-30 parts by weight, the amount of rice husk ash has a significant effect on the durability and crack resistance of concrete. When the amount is 25 parts, the impermeability grade of the concrete reaches P12, the porosity is reduced to 12%, the chloride ion permeability coefficient is the smallest, the carbonation depth is only 3.2 mm, and the comprehensive performance is the best. This is because the pozzolanic activity reaction of rice husk ash can fill the pores of concrete and improve the density, while excessive amount can reduce the alkalinity of cement-based materials and weaken the hydration reaction; insufficient amount can not fully fill the micro aggregate. The results verify the scientific rationality of the amount of rice husk ash in the invention and provide a quantitative basis for optimizing the durability of concrete in engineering applications.

[0056] Example Four: Optimization Example of Modified Natural Zeolite Amount for Anti-breaking Building Concrete Material

[0057] To study the influence of the amount of modified natural zeolite on the performance of concrete, five groups of comparative experiments were designed. Except for the amount of modified natural zeolite which was adjusted in 10-20 parts gradient, the rest of the raw material ratio remained the same: cement 320 parts, fine aggregate 550 parts, coarse aggregate 900 parts, degradable fiber package 2.5 parts, silica ash 30 parts, rice husk ash 20 parts, intelligent phase change material 8 parts, polycarboxylic acid type water reducer 4 parts, calcium sulphoaluminate type expansive agent 8 parts, and water 180 parts.

[0058] Amount of modified natural zeolite and preparation process of each group: Group 1: 10 parts of modified natural zeolite, preparation method same as Example One; Group 2: 13 parts, preparation method same as Example One; Group 3: 15 parts, same amount as Example One, preparation method same as Example One; Group 4: 18 parts, preparation method same as Example One; Group 5: 20 parts, preparation method same as Example One.

[0059] Preparation steps same as Example One: Raw material pretreatment: rice husk was calcined in a nitrogen atmosphere containing 8% oxygen at 600°C for 2.5h, and ground to pass through a 200 mesh sieve to obtain rice husk ash; starch-based material was heated and melted to wrap aramid fiber to obtain fiber package; modified natural zeolite was prepared according to the corresponding group amount.

[0060] Dry material mixing: raw materials are dry mixed at low speed of 70 rpm for 1.5 minutes, and after the addition of fiber-coated bodies and modified zeolite, high-speed stirring is performed at 110 rpm for 2.5 minutes until the fibers are uniformly dispersed.

[0061] Phase change material treatment: the intelligent phase change material is melted at 50℃, and the water reducing agent is dissolved in water, and the solution temperature is maintained at 40℃.

[0062] Wet material mixing and curing: after the mixed solution is added to the mixer, high-speed stirring is performed for 5 minutes, and after pouring, moisture curing is performed for 14 days.

[0063] The influence of modified natural zeolite on the performance of concrete is analyzed, and Table 3 is generated.

[0064]

[0065] Table 3 In summary, within the weight range of 10-20 parts, the amount of modified natural zeolite has a significant impact on the density and durability of concrete. When the amount is 15 parts, the impermeability grade of the concrete reaches P12, the porosity is reduced to 12%, the chloride ion permeability coefficient is the smallest, the carbonation depth is only 3.5mm, and the comprehensive performance is the best. This is because the micro-filler filling effect and the pozzolanic activity of the modified natural zeolite can optimize the pore structure and improve the density of the cement stone, while excessive use will lead to imbalance of the cementitious material system, and insufficient use will not fully play the filling and pozzolanic effect. The results verify the scientific rationality of the amount of modified natural zeolite in the invention, and provide a quantitative basis for improving the crack resistance and durability of concrete in engineering applications.

[0066] Example Five: Optimization of the amount of intelligent phase change material for anti-cracking building concrete material.

[0067] To study the influence of the amount of intelligent phase change material on the performance of concrete, five groups of comparative experiments were designed. Except for the amount of intelligent phase change material, which was adjusted in a gradient of 5-10 parts, the proportions of the other raw materials remained the same: cement 320 parts, fine aggregate 550 parts, coarse aggregate 900 parts, degradable fiber-coated bodies 2.5 parts, silica fume 30 parts, rice husk ash 20 parts, modified natural zeolite 15 parts, polycarboxylate-based superplasticizer 4 parts, calcium sulphoaluminate expansive agent 8 parts, and water 180 parts.

[0068] The amount of intelligent phase change material in each group and the preparation process: Group 1: 5 parts of intelligent phase change material, specifications same as Example One; Group 2: 7 parts, specifications same as Example One; Group 3: 8 parts, same amount as Example One, specifications same as Example One; Group 4: 9 parts, specifications same as Example One; Group 5: 10 parts, specifications same as Example One.

[0069] Preparation steps are the same as Example One: Raw material pretreatment: rice husk was calcined at 600℃ in a nitrogen atmosphere containing 8% oxygen for 2.5h, and ground to pass through a 200 mesh screen to obtain rice husk ash; natural zeolite was crushed and modified for use; starch-based material was wrapped around aramid fibers to obtain fiber-wrapped bodies.

[0070] Dry material mixing: the materials were dry mixed at a low speed of 70 rpm for 1.5 minutes, and then the fiber-wrapped bodies and modified zeolite were added and stirred at a high speed of 110 rpm for 2.5 minutes until the fibers were uniformly dispersed.

[0071] Phase change material treatment: the intelligent phase change material was heated to melt at 50℃ according to the corresponding group dosage, and dissolved in 180 parts of water with 4 parts of water reducing agent, keeping the solution temperature at 40℃.

[0072] Wet material mixing and curing: the mixed solution was added to the mixer within 1.5 minutes, and stirred at a high speed of 110 rpm for 5 minutes, then poured and covered with a thin film for moisture curing for 14 days.

[0073] Analyze the influence of intelligent phase change material on the performance of concrete, and generate Table 4 for comparison.

[0074]

[0075] Table 4 for comparison In summary, within the weight range of 5-10 parts, the amount of intelligent phase change material has a significant impact on the temperature stress cracking resistance and durability of concrete. When the amount is 8 parts, the temperature stress cracking index is reduced to 12, which is 52% lower than that of traditional concrete, the impermeability level reaches P12, the porosity is 12%, and the comprehensive performance is optimal. This is because the appropriate amount of phase change material absorbs or releases heat through the melting-solidification process, relieving temperature stress, and its microcapsule structure also optimizes the pore distribution. Excessive amount will dilute the cementitious material system, and insufficient amount will limit the temperature control effect. The results verify the scientificity of the amount of 8 parts in the invention, and provide a quantitative basis for balancing the temperature control and mechanical performance of concrete in engineering applications.

[0076] Example Six: Stability detection example of anti-cracking building concrete material

[0077] Based on the original Example One, select the same batch of anti-cracking concrete (with the same material ratio and preparation process), and perform performance stability detection at different curing ages (7 days, 14 days, 28 days, 60 days, 90 days), focusing on the crack resistance, durability and mechanical performance retention ability of the material in long-term use.

[0078] According to the analysis results, generate Table 5 for comparison.

[0079]

[0080] Table 5 In summary, the anti-cracking building concrete material of the present application exhibits excellent stability during long-term curing. During the curing period of 7-28 days, the tensile strength gradually increases from 3.8 MPa to 4.2 MPa, the impermeability grade increases from P10 to P12, and the porosity decreases to 12%, indicating that the internal structure of the material gradually densifies with age, which is attributed to the continuous progress of cement hydration and the pozzolanic activity reaction of rice husk ash and modified natural zeolite. At the age of 60-90 days, the tensile strength is stable at 4.3 MPa, the impermeability grade and porosity are maintained in the optimal state, and no crack propagation is detected, with a carbonation depth of only 1.5 mm, which is significantly better than traditional concrete (carbonation depth of 5.8 mm at 28 days).

[0081] The porous structure formed by the degradation of the degradable fiber inclusions after the hardening of the concrete not only relieves stress concentration in the early stage, but also optimizes the pore distribution in cooperation with the modified zeolite in long-term use, preventing the intrusion of harmful substances. The microcapsule structure of the intelligent phase change material remains stable during long-term curing without rupture or performance degradation, ensuring the continuous and effective temperature control function of the material. The test results confirm that the material of the present application can maintain excellent crack resistance, durability and mechanical properties during long-term service, and is suitable for high-rise building engineering with high stability requirements.

[0082] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present application. Any modification, equivalent change and modification of the above embodiments made in accordance with the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A fracture-resistant building concrete material, characterized in that: The concrete material comprises the following raw materials in parts by weight: Cement: 280-380 parts; Fine aggregate: 500-600 parts; Coarse aggregate: 800-1000 parts; Degradable fiber inclusions: 1.5-3.5 parts; Silica fume: 20-40 parts; Rice husk ash: 15-30 parts; Modified natural zeolite: 10-20 parts; Smart phase change material: 5-10 parts; Polycarboxylic acid water reducer: 3-5 parts; Calcium sulfoaluminate expansion agent: 5-10 parts; Water: 150-200 parts.

2. The anti-fracture building concrete material according to claim 1, characterized in that: The degradable fiber inclusion body is prepared by wrapping aramid fiber with a starch-based degradable material, and the thickness of the inclusion layer is controlled to be 5-8 μm.

3. The anti-fracture building concrete material according to claim 2, characterized in that: The aramid fiber is the core material and has a diameter of 10-15 μm.

4. The anti-fracture building concrete material according to claim 2, characterized in that: The starch-based biodegradable material comprises, by weight, 70-80 parts of starch, 10-15 parts of polybutylene adipate / terephthalate (PBAT), and 5-10 parts of a plasticizer, wherein the plasticizer is one of glycerol and sorbitol, or a mixture of glycerol and sorbitol in a weight ratio of 1:

1.

5. The anti-fracture building concrete material according to claim 1, characterized in that: The rice husk ash is prepared by calcining the rice husk at a temperature of 600-800° C. in a nitrogen atmosphere containing 5-10% oxygen for 2-3 hours, and then grinding the rice husk with a jet mill until it passes through a 200-mesh sieve.

6. The anti-fracture building concrete material according to claim 1, characterized in that: The preparation method of the modified natural zeolite is as follows: the natural zeolite is crushed to a particle size of ≤2 mm and then sieved, soaked in a 5% silane coupling agent KH-550 ethanol solution at a solid-liquid ratio of 1:5 at 60°C for 2 hours, then dried at 80°C for 4 hours, and then ground to a D50 particle size of 10-15 μm to obtain a specific surface area of ​​≥800 m 2 / g of modified natural zeolite.

7. The anti-fracture building concrete material according to claim 1, characterized in that: The intelligent phase change material is n-octadecane encapsulated in melamine resin microcapsules, the microcapsule particle size is 50-100 μm, the wall thickness is 1-3 μm, the phase change temperature is 20-25° C., and the phase change latent heat is 150-200 J / g.

8. A method for preparing a fracture-resistant building concrete material, the method being used to prepare the fracture-resistant building concrete material according to any one of claims 1 to 7, characterized in that: The specific steps of the preparation method are: S100, raw material pretreatment: calcining rice husks at 600-800°C for 2-3 hours and grinding them through a 200-mesh sieve to obtain rice husk ash; crushing and sieving natural zeolite, soaking it in a 5% silane coupling agent ethanol solution for 2 hours, and drying it for later use; heating and melting the starch-based biodegradable material, and then evenly wrapping it around aramid fibers to obtain a fiber inclusion; S200, dry material mixing: Add cement, fine aggregate, coarse aggregate, silica fume, rice husk ash, and expansion agent into a forced mixer according to the proportion, dry mix at a low speed of 60-80 rpm for 1-2 minutes, then add the biodegradable fiber inclusions and modified zeolite, and stir at a high speed of 100-120 rpm for 2-3 minutes until the fibers are evenly dispersed; S300, phase change material treatment: heat and melt the smart phase change material at 40-60°C, dissolve it in water together with a polycarboxylic acid-based water reducer, and prepare a mixed solution; S400, wet material mixing: Under stirring, slowly add the mixed solution into the mixer within 1-2 minutes, and stir at a high speed of 100-120 rpm for 4-6 minutes until the slurry is uniform to obtain anti-fracture concrete.

9. The method for preparing a fracture-resistant building concrete material according to claim 1, characterized in that: In the above-mentioned S300, the temperature of the mixed solution in the phase change material treatment needs to be maintained at 30-50°C.

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