Rapid-infiltration water-absorption expansion joint concrete material as well as preparation method and application thereof

Abstract

The invention relates to a rapid-infiltration water-absorption expansion joint concrete material as well as a preparation method and application thereof. The rapid-infiltration water-absorption expansion joint concrete material comprises a cementing material, aggregate, a rapid-infiltration water-absorption component, an additive and water, the expansion joint concrete material is obtained by sequentially premixing the quick-infiltration water-absorbing component, mixing the cementing material and the aggregate, adding the additive and the water and fusing the functional premix. According to the invention, the four functions of rapid rainwater drainage, adaptive structure expansion, external force impact bearing and long-acting water and seepage prevention can be realized, the material can rapidly dredge accumulated water in gaps and actively absorb water to expand and seal, and meanwhile, the material has excellent mechanical strength, expansion adaptability and base material bonding performance; the problems that a traditional expansion joint material is insufficient in seepage drainage and deformation adaptability and unbalanced in strength and durability are solved, the expansion joint material is suitable for concrete expansion joint projects under various complex working conditions, the service life of structures is prolonged, and the construction concepts of green buildings and sponge cities are met.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a fast-absorbing and water-absorbing expansion joint concrete material, its preparation method, and its application. Background Technology

[0002] Expansion joints in concrete structures are structural gaps designed to release stress caused by temperature changes and structural settlement. Their sealing, waterproofing, and expansion / contraction adaptability directly determine the structural durability. Currently, the concrete materials used to fill expansion joints mainly include asphalt-based binders, water-swellable sealing strips, silicone rubber sealants, and high-performance concrete fillers. However, all of these materials have several technical shortcomings. While asphalt-based materials possess a certain degree of elasticity, they exhibit poor aging resistance and are prone to cracking and detachment upon prolonged exposure, leading to water seepage problems. Furthermore, they lack the ability to actively absorb and regulate water. Water-swellable sealing strips rely on water absorption and expansion to achieve a seal, but their slow penetration rate makes them unable to quickly drain water accumulated in gaps. Moreover, their strength is insufficient after expansion, making them susceptible to damage from structural expansion and contraction, and they are difficult to restore to their original shape after drying. Silicone rubber sealants offer excellent elasticity but are costly, have limited adhesion strength to concrete substrates, and lack water absorption capabilities, allowing water to remain in gaps for extended periods and corrode the structure. High-performance concrete fillers develop strength rapidly but have poor permeability, failing to solve the problem of water accumulation in gaps. They also lack adaptability to expansion and contraction, making them prone to cracking due to structural deformation.

[0003] Therefore, in order to address the above problems, there is an urgent need to develop an expansion joint concrete material that combines rapid penetration, efficient water absorption, high strength, high elasticity, and good adhesion. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a fast-absorbing and water-absorbing expansion joint concrete material, its preparation method, and its application. The prepared concrete material can quickly drain water accumulated in the gaps and actively absorb water to expand and seal. At the same time, it has excellent mechanical strength, expansion adaptability, and adhesion performance with the substrate, realizing the synergistic function of "rapid drainage - water absorption expansion sealing - structural adaptation", improving the waterproof durability and service life of the expansion joint. It solves the problems of insufficient drainage and deformation adaptability, and imbalance between strength and durability of traditional expansion joint materials. It is suitable for concrete expansion joint projects under various complex working conditions, extending the service life of structures and conforming to the concepts of green building and sponge city construction.

[0005] The technical problem solved by this invention is achieved through the following technical solution: A fast-absorbing and water-absorbing expansion joint concrete material, wherein the material comprises the following components by weight: Cementitious material: 30-45 parts; composed of 60-70% ordinary Portland cement, 20-30% ultrafine slag powder, and 5-10% silica fume; Aggregate: 40-55 parts, using graded modified manufactured sand with a particle size range of 0.15-5mm; fine sand with a particle size of 0.15-0.6mm accounts for 30-40%, coarse sand with a particle size of 2.5-5mm accounts for 40-50%, and the remainder is medium sand; Rapidly absorbent water-absorbing component: 8-15 parts; including 3-5 parts of superabsorbent polymer, 2-4 parts of expanded graphite, 2-3 parts of modified lignin, and 1-3 parts of hydrophilic fiber; Admixtures: 2-5 parts; including 1-2 parts of ultra-high performance water-reducing agent, 0.5-1 part of nanocrystalline nucleation early strength agent, 0.3-0.8 parts of organosilicon-modified polyether end-capping agent, and 0.2-0.5 parts of multifunctional composite catalyst; Water: 8-12 parts, using tap water or purified water, with a water-to-cement ratio of 0.22-0.28.

[0006] Moreover, the specific surface area of ​​the ultrafine slag powder is ≥450m². 2 / kg, with an average particle size of silica fume ≤1μm.

[0007] Furthermore, the superabsorbent polymer is a starch-grafted acrylate copolymer with a water absorption ratio of 200-400 times and a particle size of 100-200 mesh; the expanded graphite has a particle size of 50-100 mesh; the modified lignin is modified from alkali lignin with acrylamide hydrophilic monomers and crosslinking agents, and is further improved by oxidation to enhance dispersibility; the hydrophilic fiber is a modified polypropylene fiber with a length of 6-12 mm.

[0008] Moreover, the ultra-high performance water-reducing agent is polycarboxylate-based, with a water reduction rate of ≥30%.

[0009] Furthermore, the concrete material exhibits the following characteristics: 3-day compressive strength ≥ 35 MPa, 28-day compressive strength ≥ 50 MPa, tensile bond strength ≥ 0.6 MPa, elastic recovery rate ≥ 95%, applicable expansion / contraction ≤ 80 mm, and 30-minute water penetration rate ≥ 5.0 × 10⁻⁶. -3 cm / s, and the water absorption swelling rate reaches 2.0% in 24 hours.

[0010] A method for preparing a fast-absorbing and water-permeable expansion joint concrete material, comprising the following steps: S1. Place the superabsorbent polymer, expanded graphite, modified lignin and hydrophilic fiber of the fast-penetrating water-absorbing component into a high-speed mixer and stir at room temperature for 5 to 8 minutes at a speed of 800 to 1000 r / min to make the components evenly dispersed and form a functional premix to ensure that the water absorption and permeation functions work synergistically. S2. Add the cementitious materials and aggregates to the planetary mixer and stir for 300-400 r / min for 3-5 minutes until the mixture is uniform in color. S3. Add the additive to the mixture in S2 and slowly add the preset amount of water. Stir at 400-500 r / min for 6-10 minutes to form a uniform viscous slurry. Control the slurry spread to 200-250 mm. S4. Add the functional premix prepared in S1 to the slurry in S3, adjust the speed to 600~700r / min and stir for 4~6 minutes to ensure that the fast-permeable and water-absorbing components are evenly dispersed in the slurry to form a three-dimensional network permeable and water-absorbing structure, and prepare the fast-permeable and water-absorbing expansion joint concrete material.

[0011] The application of a fast-absorbing and water-absorbing expansion joint concrete material in expansion joint filling involves filling the expansion joint with the expansion joint concrete material; after construction, moist curing is adopted, and the material can reach the service strength after 3 days of curing at room temperature. During the curing period, exposure to sunlight and water immersion should be avoided to ensure the stable development of material performance.

[0012] The advantages and beneficial effects of this invention are as follows: 1. Rapid water penetration and efficient water absorption: By constructing interconnected pores through graded aggregates and combining them with expanded graphite seepage channels, the water penetration rate is 3 to 5 times higher than that of traditional water-swellable materials, which can quickly drain water accumulated in expansion joints; the superabsorbent polymer absorbs water and expands rapidly, with an expansion rate of 200 to 400%, forming a dense and elastic sealing layer, realizing the integrated function of "seepage-water absorption-sealing".

[0013] 2. Excellent mechanical properties and elastic adaptability: 3-day compressive strength ≥35MPa, 28-day compressive strength ≥50MPa, tensile bond strength ≥0.6MPa, capable of withstanding structural expansion and contraction compression and vehicle loads; elastic recovery rate ≥95%, adaptable to expansion and contraction of less than 80mm, no noise when cars drive over, high driving comfort.

[0014] 3. High durability: The composite modification of cementitious materials and the synergistic effect of additives give the material excellent resistance to ultraviolet rays, aging, and freeze-thaw, with an operating temperature range of -40℃ to 150℃ and a service life of more than 15 years; it can return to its original shape after drying and has stable repeated water absorption and expansion performance.

[0015] 4. Convenient construction and controllable cost: No special construction equipment is required. After mixing, it can be directly filled, and the construction efficiency is more than 40% higher than that of traditional seamless expansion joint materials. The raw materials are readily available, and the cost is 30-50% lower than that of silicone rubber sealant, making it suitable for large-scale engineering applications. Detailed Implementation

[0016] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0017] Example 1 A fast-permeable and water-absorbing expansion joint concrete material comprises, by weight: 35 parts of cementitious material (24.5 parts of ordinary silicate cement, 7 parts of ultrafine slag powder, and 3.5 parts of silica fume), 48 parts of aggregate (14.4 parts of fine sand, 9.6 parts of medium sand, and 24 parts of coarse sand), 11 parts of fast-permeable and water-absorbing component (4 parts of superabsorbent polymer, 3 parts of expanded graphite, 2 parts of modified lignin, and 2 parts of hydrophilic fiber), 3.5 parts of admixture (1.5 parts of ultra-high performance water-reducing agent, 0.8 parts of nanocrystalline nucleation early strength agent, 0.6 parts of organosilicon modified polyether end-capping agent, and 0.6 parts of multifunctional composite catalyst), and 10 parts of water.

[0018] Preparation method: Premix the fast-absorbing water-absorbing component in sequence (stir at 900 r / min for 6 minutes), mix the cementitious material and aggregate (stir at 350 r / min for 4 minutes), add the admixture and water (stir at 450 r / min for 8 minutes), and blend the functional premix (stir at 650 r / min for 5 minutes). After discharge, fill the expansion joints and cure at room temperature for 3 days.

[0019] The performance of the prepared concrete material was tested: water permeation rate 0.8 mL / (cm²). 2 It has a water absorption expansion rate of 320%, a 3-day compressive strength of 38MPa, a 28-day compressive strength of 52MPa, a tensile bond strength of 0.7MPa, an elastic recovery rate of 96%, and is suitable for expansion joints with a shrinkage of ≤80mm. It meets the requirements for use in large tunnels and bridge expansion joints.

[0020] Example 2 A fast-permeable and water-absorbing expansion joint concrete material comprises, by weight: 30 parts of cementitious material (18 parts of ordinary silicate cement, 9 parts of ultrafine slag powder, and 3 parts of silica fume), 55 parts of aggregate (16.5 parts of fine sand, 11 parts of medium sand, and 27.5 parts of coarse sand), 8 parts of fast-permeable and water-absorbing component (3 parts of superabsorbent polymer, 2 parts of expanded graphite, 2 parts of modified lignin, and 1 part of hydrophilic fiber), 2.5 parts of admixture (1 part of ultra-high performance water-reducing agent, 0.5 parts of nanocrystalline nucleation early strength agent, 0.5 parts of organosilicon modified polyether end-capping agent, and 0.5 parts of multifunctional composite catalyst), and 8 parts of water.

[0021] Preparation method: Premix the fast-absorbing water-absorbing component (stir at 800 r / min for 5 minutes), mix the cementitious material and aggregate (stir at 300 r / min for 3 minutes), add the admixture and water (stir at 400 r / min for 6 minutes), and blend the functional premix (stir at 600 r / min for 4 minutes). Cured at room temperature with moisture for 3 days.

[0022] The performance of the prepared concrete material was tested: water permeation rate was 0.6 mL / (cm). 2It has a water absorption expansion rate of 280%, a 3-day compressive strength of 35MPa, a 28-day compressive strength of 50MPa, a tensile bond strength of 0.6MPa, and an elastic recovery rate of 95%. It is suitable for building roofs and small bridge expansion joints.

[0023] Example 3 A fast-permeable and water-absorbing expansion joint concrete material comprises, by weight: 45 parts of cementitious material (31.5 parts of ordinary silicate cement, 9 parts of ultrafine slag powder, and 4.5 parts of silica fume), 40 parts of aggregate (16 parts of fine sand, 8 parts of medium sand, and 16 parts of coarse sand), 15 parts of fast-permeable and water-absorbing component (5 parts of superabsorbent polymer, 4 parts of expanded graphite, 3 parts of modified lignin, and 3 parts of hydrophilic fiber), 5 parts of admixture (2 parts of ultra-high performance water-reducing agent, 1 part of nanocrystalline nucleation early strength agent, 0.8 parts of organosilicon modified polyether end-capping agent, and 1.2 parts of multifunctional composite catalyst), and 12 parts of water.

[0024] Preparation method: Premix the fast-absorbing water-absorbing component (stir at 1000 r / min for 8 minutes), mix the cementitious material and aggregate (stir at 400 r / min for 5 minutes), add the admixture and water (stir at 500 r / min for 10 minutes), and blend the functional premix (stir at 700 r / min for 6 minutes). Cured at room temperature with moisture for 3 days.

[0025] The performance of the prepared concrete material was tested: water permeation rate 1.0 mL / (cm²). 2 With a water absorption expansion rate of 380%, a 3-day compressive strength of 42MPa, a 28-day compressive strength of 58MPa, a tensile bond strength of 0.8MPa, and an elastic recovery rate of 97%, it is suitable for highway expansion joints with high loads and large expansion and contraction.

[0026] Although embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the scope of the invention is not limited to the contents disclosed in the embodiments.

Claims

1. A fast-absorbing and water-absorbing expansion joint concrete material, characterized in that: The material comprises the following components in parts by weight: Cementitious material: 30-45 parts; composed of 60-70% ordinary Portland cement, 20-30% ultrafine slag powder, and 5-10% silica fume; Aggregate: 40-55 parts, using graded modified manufactured sand with a particle size range of 0.15-5mm; fine sand with a particle size of 0.15-0.6mm accounts for 30-40%, coarse sand with a particle size of 2.5-5mm accounts for 40-50%, and the remainder is medium sand; Rapidly absorbent water-absorbing component: 8-15 parts; including 3-5 parts of superabsorbent polymer, 2-4 parts of expanded graphite, 2-3 parts of modified lignin, and 1-3 parts of hydrophilic fiber; Additive: 2-5 parts; It includes 1-2 parts of ultra-high performance water-reducing agent, 0.5-1 part of nanocrystalline nucleus early strength agent, 0.3-0.8 parts of organosilicon modified polyether end-capping agent, and 0.2-0.5 parts of multifunctional composite catalyst; Water: 8-12 parts, using tap water or purified water, with a water-to-cement ratio of 0.22-0.

28.

2. The rapid-penetrating and water-absorbing expansion joint concrete material according to claim 1, characterized in that: The ultrafine slag powder has a specific surface area ≥450m². 2 / kg, with an average particle size of silica fume ≤1μm.

3. The rapid-penetrating and water-absorbing expansion joint concrete material according to claim 1, characterized in that: The superabsorbent polymer is a starch-grafted acrylate copolymer with a water absorption ratio of 200-400 times and a particle size of 100-200 mesh; the expanded graphite has a particle size of 50-100 mesh; the modified lignin is made by modifying alkali lignin with acrylamide hydrophilic monomers and crosslinking agents, and is further improved by oxidation to enhance dispersibility; the hydrophilic fiber is a modified polypropylene fiber with a length of 6-12 mm.

4. The rapid-penetrating and water-absorbing expansion joint concrete material according to claim 1, characterized in that: The ultra-high performance water-reducing agent is polycarboxylate-based, with a water reduction rate of ≥30%.

5. The rapid-penetrating and water-absorbing expansion joint concrete material according to claim 1, characterized in that: The concrete material has a 3-day compressive strength ≥35MPa, a 28-day compressive strength ≥50MPa, a tensile bond strength ≥0.6MPa, an elastic recovery rate ≥95%, an applicable expansion / contraction ≤80mm, and a 30-minute water penetration rate ≥5.0×10⁻⁶. -3 cm / s, and the water absorption swelling rate reaches 2.0% in 24 hours.

6. A method for preparing a fast-absorbing and water-absorbing expansion joint concrete material, characterized in that: The method for preparing the expansion joint concrete material as described in any one of claims 1 to 5 comprises the following steps: S1. Place the superabsorbent polymer, expanded graphite, modified lignin and hydrophilic fiber of the fast-penetrating water-absorbing component into a high-speed mixer and stir at room temperature for 5 to 8 minutes at a speed of 800 to 1000 r / min to make the components evenly dispersed and form a functional premix to ensure that the water absorption and permeation functions work synergistically. S2. Add the cementitious materials and aggregates to the planetary mixer and stir for 300-400 r / min for 3-5 minutes until the mixture is uniform in color. S3. Add the additive to the mixture in S2 and slowly add the preset amount of water. Stir at 400-500 r / min for 6-10 minutes to form a uniform viscous slurry. Control the slurry spread to 200-250 mm. S4. Add the functional premix prepared in S1 to the slurry in S3, adjust the speed to 600~700r / min and stir for 4~6 minutes to ensure that the fast-permeable and water-absorbing components are evenly dispersed in the slurry to form a three-dimensional network permeable and water-absorbing structure, and prepare the fast-permeable and water-absorbing expansion joint concrete material.

7. An application of the fast-absorbing and water-absorbing expansion joint concrete material as described in any one of claims 1 to 5 in the filling of expansion joints, wherein the expansion joint concrete material is filled into the expansion joint; after construction, moist curing is adopted, and the service strength can be reached after 3 days of curing at room temperature; during the curing period, exposure to sunlight and immersion in water should be avoided to ensure the stable development of material performance.