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CN-122010492-A - High-strength weather-proof self-repairing ultra-high-performance concrete and preparation method thereof

CN122010492ACN 122010492 ACN122010492 ACN 122010492ACN-122010492-A

Abstract

The invention discloses high-strength weather-proof self-repairing ultra-high performance concrete and a preparation method and application thereof, and belongs to the technical field of building materials. The concrete comprises a gel material, quartz sand aggregate, polyester composite fiber, a composite high-efficiency water reducing agent and water, wherein the gel material is prepared by compounding portland cement and silica fume, the composite high-efficiency water reducing agent is prepared by grafting internal curing microspheres and aminated drug-loaded nano silica after activation of a polycarboxylic acid water reducing agent, and the preparation method comprises the steps of premixing raw materials, adding a functional agent aqueous solution, stirring, molding and curing. Aiming at the problems that the prior art is difficult to cooperate with high strength and weather resistance, the functional auxiliary agent has tolerance and low self-repairing efficiency, and the like, the invention realizes that the compressive strength of the concrete is more than or equal to 120MPa, the retention rate of 300 times of freeze thawing cycle performance is 100 percent, and the self-repairing rate of microcracks within 0.3mm is more than or equal to 95 percent through component modification and functional integrated design, and is suitable for severe scenes such as building external decoration, bridges and the like.

Inventors

  • WANG HUA

Assignees

  • 江苏莫尼埃新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260209

Claims (6)

  1. 1. The high-strength weather-proof self-repairing ultra-high performance concrete is characterized by comprising the following raw materials in percentage: 930-1330 parts of gel material, wherein the gel material is prepared by compounding portland cement and silica fume according to a mass ratio of 70-101:23-32; 760-1280 parts of quartz sand aggregate, wherein the quartz sand aggregate is formed by mixing superfine quartz sand with the particle size of 0.1-0.3mm and white fine sand with the particle size of 0.3-1.0mm according to the mass ratio of 0-23:76-105; 50-190 parts of polyester composite fiber, wherein the polyester composite fiber is prepared by compounding polyethylene terephthalate with the diameter of 0.15-0.3mm and the length of 10-15mm with basalt fiber according to the mass ratio of 80:20, and modifying by a silane coupling agent; 15-25 parts of a composite high-efficiency water reducer, wherein the composite high-efficiency water reducer is prepared from a commercial polycarboxylate water reducer serving as a base material, activated, grafted hydroxyl-terminated polyethylene glycol internal curing microspheres and aminated drug-carrying nano silicon dioxide; 155-210 parts of water; water/cementing material ratio of 0.1-0.12.
  2. 2. The high-strength weather-proof self-repairing ultra-high performance concrete according to claim 1, wherein the preparation method of the polyester composite fiber is characterized in that polyethylene terephthalate and basalt fiber are placed into mixed modified liquid with the mass ratio of gamma-aminopropyl triethoxysilane, absolute ethyl alcohol and deionized water being 1:10:3 according to the mass ratio of 80:20, stirred and soaked for 1h at 60-80 ℃, stirred once every 15min to ensure that the surface of the fiber is uniformly contacted with the modified liquid, dried to constant weight at 80-100 ℃ after being taken out, cooled to room temperature, and agglomerated particles are removed through a sieve of 0.15mm, thus obtaining the polyester composite fiber.
  3. 3. The high-strength weather-resistant self-repairing ultra-high performance concrete according to claim 1, wherein the preparation method of the composite high-efficiency water reducer is as follows: s1, carboxyl activation of a polycarboxylic acid water reducer: Diluting the polycarboxylic acid water reducer solution with deionized water to a solid content of 20%, adding a carbodiimide condensing agent and N-hydroxysuccinimide under the cooling and stirring of ice water bath, wherein the amount of the condensing agent is 1.0-1.2 times of the molar number of carboxyl in the polycarboxylic acid water reducer, the amount of the N-hydroxysuccinimide is equivalent to that of the condensing agent, and stirring and reacting for 2-4 hours at room temperature to obtain an activated polycarboxylic acid water reducer solution; S2, grafting a functional unit: Heating to 40-50 ℃, regulating pH to 5-7, slowly adding hydroxyl-terminated polyethylene glycol to maintain microsphere and aminated drug-carrying nano silicon dioxide, reacting for 4-8h under heat preservation, pumping into a spray dryer, controlling air inlet temperature to 180-200 ℃, air outlet temperature to 80-90 ℃ and atomization pressure to 0.3-0.5MPa, and obtaining the composite high-efficiency water reducer.
  4. 4. The high-strength weather-proof self-repairing ultra-high performance concrete according to claim 3, wherein the preparation method of the aqueous dispersion liquid of the hydroxyl-terminated polyethylene glycol internal curing microsphere is as follows: Mixing 45 parts of polyethylene glycol, 6 parts of acrylic acid and 0.4 part of N, N' -methylene bisacrylamide uniformly, adding 110 parts of liquid paraffin containing 4 parts of emulsifier, stirring for 5min, heating to 65 ℃, adding 0.4 part of potassium persulfate, reacting for 2h under heat, filtering while the mixture is hot, washing with absolute ethyl alcohol for 2 times, and drying to obtain the hydroxyl-terminated polyethylene glycol internal curing microsphere.
  5. 5. The high-strength weather-resistant self-repairing ultra-high performance concrete according to claim 3, wherein the preparation method of the aqueous dispersion liquid of the amination drug-loaded nano silicon dioxide is as follows: 13 parts of sodium silicate and 6 parts of lithium carbonate are dissolved in 90 parts of deionized water to prepare a repairing agent aqueous solution, 22 parts of tetraethoxysilane and 55 parts of ethanol are uniformly mixed, the repairing agent aqueous solution is slowly added, stirring is carried out for 30min, the pH is regulated to 9.5 by ammonia water, the temperature is raised to 45 ℃, the reaction is kept at the temperature for 4 hours, 4 parts of silane coupling agent KH-550 is added, the reaction is continued for 2 hours, the mixture is kept stand for layering, the deionized water is washed for 2 times, and the amination medicine carrying nano silicon dioxide is obtained after drying.
  6. 6. The method for preparing the high-strength weather-resistant self-repairing ultra-high performance concrete according to any one of claims 1 to 5, which is characterized by comprising the following steps of (1) Weighing gel materials and quartz sand aggregates according to the proportion, and putting the gel materials and the quartz sand aggregates into a stirrer to be dried and stirred for 2-3min; (2) Adding the polyester composite fiber into the mixture in the step (1), and continuously stirring for 1-2min; (3) Uniformly mixing the composite high-efficiency water reducer with deionized water to prepare an aqueous solution, slowly adding the aqueous solution into the mixture obtained in the step (2), and stirring for 3-5min; (4) Pouring the mixture into a mould, vibrating and molding, curing for 24 hours under the conditions of 20+/-2 ℃ and the relative humidity of more than or equal to 90%, demoulding, and curing for 72 hours in a steam environment of 80-90 ℃ to obtain the finished concrete.

Description

High-strength weather-proof self-repairing ultra-high-performance concrete and preparation method thereof Technical Field The invention relates to the technical field of building materials, in particular to high-strength weather-proof self-repairing ultra-high-performance concrete and a preparation method thereof. Background The ultra-high performance concrete (UHPC) is a key material of severe scenes such as building external decoration, bridge structures and the like by virtue of the core advantages of low porosity and high strength, and the service life and safety of engineering under extreme environments such as severe cold, seaside, chemical factories and the like are directly determined by the ultra-high strength and the excellent weather resistance. Along with the continuous upgrading of engineering to material performance requirements, the market needs to integrate UHPC with high strength, high weather resistance and self-repairing functions, but the traditional technology is difficult to balance multi-performance cooperation, and becomes an industry technology pain point. In order to achieve the aim of high strength and weather resistance, the prior art optimizes the performance by improving the activity of the cementing material, reducing the water-gel ratio or adding a single functional auxiliary agent, and simultaneously tries to adopt common aggregate and fiber collocation to attempt to strengthen the structural compactness of the material. Some of the solutions are aimed at improving weatherability by adding antifreeze agents, corrosion inhibitors alone, or for high strength by increasing the fiber loading. However, the existing solution has obvious defects that firstly, the internal shrinkage cracking of materials is easy to cause in pursuit of high strength to reduce the water-gel ratio, the weather resistance is weakened instead, the cooperative improvement of the two is difficult to realize, secondly, in the mode of multi-dose combined use, the compatibility of functional auxiliary agents is poor, the functions of water reduction, maintenance and repair are mutually interfered, the exertion of high-strength and high weather resistance is further restricted, thirdly, the aggregate and the fiber are not subjected to targeted modification, and are combined with a cementing matrix interface to be weak, so that micro defects are formed, the strength stability and weather resistance durability are affected, and thirdly, the self-repair function is low in efficiency, the micro cracks in the service process cannot be repaired in time, the high-strength and high weather resistance can be continuously attenuated, and part of the processes are complex, so that the large-scale application is difficult. Disclosure of Invention The invention aims to solve the defects in the prior art, and provides high-strength weather-resistant self-repairing ultra-high-performance concrete and a preparation method thereof. In order to achieve the above purpose, the present invention adopts the following technical scheme: S1, preparing a composite high-efficiency water reducer: S101, diluting a polycarboxylic acid water reducer solution with deionized water to a solid content of 20%, adding a carbodiimide condensing agent and N-hydroxysuccinimide under the condition of cooling and stirring in an ice water bath, wherein the amount of the condensing agent is 1.0-1.2 times of the molar number of carboxyl in the polycarboxylic acid water reducer, the amount of the N-hydroxysuccinimide is equivalent to that of the condensing agent, and stirring and reacting for 2-4 hours at room temperature to obtain an activated polycarboxylic acid water reducer solution; the core of the step is carboxyl activation, wherein the reaction is carbodiimide-mediated carboxyl activation reaction, belongs to active ester preparation reaction in organic synthesis, and aims to activate carboxyl (-COOH) on a molecular chain of a polycarboxylic acid water reducer into N-hydroxysuccinimide ester (-COONHS) which is easier to react with hydroxyl (-OH) and amino (-NH 2), and lays a foundation for covalent grafting of a subsequent functional unit, and the process is divided into two steps; In an ice water bath environment, isocyanate groups (-N=C=N-) in molecules of the carbodiimide condensing agent have high reactivity, one end nitrogen atom of the isocyanate groups can attack carboxyl carbon in R-COOH, then proton transfer and elimination reaction are carried out to form an O-acyl isourea intermediate, and the ice water bath has the functions of inhibiting the self-hydrolysis of the condensing agent and improving the intermediate generation efficiency; Secondly, N-hydroxysuccinimide is taken as a nucleophilic reagent to attack the acyl carbon of the O-acyl isourea intermediate to replace the original isourea group, so as to form thermodynamically stable active ester (R-COONHS), the acyl carbon electrophilicity of the active ester is obviously enhanced,