Search

CN-122010503-A - Cracking-resistant concrete and production process thereof

CN122010503ACN 122010503 ACN122010503 ACN 122010503ACN-122010503-A

Abstract

The invention relates to the technical field of building materials, provides anti-cracking concrete and a production process thereof, and solves the problems of failure, high cracking risk and insufficient durability of a concrete water reducer in a high-mud-sand-content environment; the alkali-resistant reinforced fiber comprises an inorganic gel system, fine aggregates, coarse aggregates, mixed water, a composite water reducer, modified magnesium aluminum hydrotalcite, alkali-resistant reinforced fibers and potassium stearate, wherein the composite water reducer is of a core-shell structure and comprises a shell layer and a core layer, the shell layer is a polymer network formed by copolymerizing acrylamide, acrylic acid and light-colored N-acyl amino acid phosphate, the core layer is modified Bayer process white mud, the modified magnesium aluminum hydrotalcite comprises magnesium chloride, aluminum sulfate, potassium hydroxide, nano SiO 2 , gamma-aminopropyl triethoxysilane, isopropanol and ethylene glycol, and the alkali-resistant reinforced fibers are carbon nanotubes with an organosilicon coating on the surface.

Inventors

  • LIU CHUANG
  • FANG JINQIANG

Assignees

  • 福建省五建建设集团有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (8)

  1. 1. The cracking-resistant concrete is characterized by comprising, by weight, 280-420 parts of an inorganic gel system, 600-700 parts of fine aggregate, 950-1050 parts of coarse aggregate, 120-150 parts of mixing water, 0.6-1.0 part of a composite water reducer, 1.2-1.8 parts of modified magnesium aluminum hydrotalcite, 0.05-0.12 part of alkali-resistant reinforcing fibers and 0.2-0.4 part of potassium stearate; The inorganic gelling system comprises a silicate gelling component and an auxiliary gelling component, wherein the auxiliary gelling component is a mixture of steel slag powder and zeolite powder mixed according to the mass ratio of (1-2): 1, the mass ratio of the silicate gelling component to the auxiliary gelling component is (3-5): 1, and the silicate gelling component is ordinary portland cement; The composite water reducer is of a core-shell structure and comprises a shell layer and a core layer, wherein the shell layer is a polymer network formed by copolymerizing acrylamide, acrylic acid and light-colored N-acyl amino acid phosphate, and the core layer is modified Bayer process white mud; the modified magnesium aluminum hydrotalcite comprises the following raw materials of magnesium chloride, aluminum sulfate, potassium hydroxide, nano SiO 2 , gamma-aminopropyl triethoxysilane, isopropanol and ethylene glycol; the alkali-resistant reinforced fiber is a carbon nanotube with an organosilicon coating on the surface, and the organosilicon coating consists of methyl silicone resin, silver nanowires, graphene oxide and mercaptosilane.
  2. 2. The cracking-resistant concrete according to claim 1, wherein the preparation method of the composite water reducing agent comprises the following steps: a. Dispersing Bayer process white mud in a mixed solution of ethanol and water, adding phytic acid and calcium gluconate according to the mass ratio of (0.05-0.15) to (0.1-0.2) of the Bayer process white mud to the phytic acid and the calcium gluconate, and carrying out mineralization reaction for 1-3 hours at normal temperature and normal pressure to form a white microsphere carrier with passivated surface, thus obtaining modified Bayer process white mud; b. Using tall oil as a hydrophobic base raw material, carrying out amidation reaction on the tall oil and the L-lysine according to the mol ratio of the tall oil to the L-lysine of 1 (1-1.2), and then carrying out phosphorylation modification to obtain light-color N-acyl amino acid phosphate; c. C, dispersing the white microsphere carrier prepared in the step a and the light-colored N-acyl amino acid phosphate prepared in the step S2 in a polycarboxylic acid mother solution, adding acrylamide and acrylic acid monomers, and carrying out graft copolymerization on the surface of the white microsphere carrier through a free radical initiator, wherein the mass ratio of the white microsphere carrier to the light-colored N-acyl amino acid phosphate to the acrylamide to the acrylic acid monomers is (5-10): 1-3): 2-5): 1-3, and forming a high polymer network after the graft copolymerization reaction is finished, so as to obtain the composite water reducer.
  3. 3. The cracking-resistant concrete according to claim 1, wherein the modified magnesium aluminum hydrotalcite is prepared by the following steps: I. MgCl 2 、Al 2 (SO 4 ) 3 is dissolved in deionized water according to the mol ratio of (1.5-2.5): 1, potassium hydroxide and nano SiO 2 are added, and hydrothermal reaction is carried out for 8-16 h at 100-140 ℃ to form a precursor; II. Dissolving a silane coupling agent gamma-aminopropyl triethoxysilane in a mixed solution of isopropanol and ethylene glycol, and uniformly stirring to prepare a silane mixed solution with the mass concentration of 3-8%; and III, carrying out ultrasonic dispersion treatment on the precursor prepared in the step I by using the silane mixed solution prepared in the step II, after the ultrasonic dispersion treatment is finished, carrying out suction filtration treatment, washing a filter cake with isopropanol for 2-3 times, sending the filter cake into a vacuum drying oven for drying at 60-90 ℃, and grinding and sieving with a 200-mesh sieve to obtain the modified magnesium aluminum hydrotalcite.
  4. 4. The cracking-resistant concrete according to claim 1, wherein the alkali-resistant reinforcing fiber is prepared by the following steps: (1) Dissolving methyl silicone resin in a mixed solvent of ethanol and water, sequentially adding silver nanowires, graphene oxide and a mercapto silane coupling agent, and treating for 15-20 min by using a high-speed shearing emulsifying machine at 60-80 ℃ to form uniform mixed slurry; (2) Adding carbon nanotubes into the mixed slurry prepared in the step (1), performing ultrasonic dispersion treatment, performing solid-liquid separation by a centrifuge, discarding supernatant, and drying the collected solid precipitate in a vacuum drying oven at 80-100 ℃ for 6-8 h to obtain alkali-resistant reinforced fibers; the silver nanowire is added in an amount of 5-10% of the mass of the methyl silicone resin, the graphene oxide is added in an amount of 1-3% of the mass of the methyl silicone resin, and the mercapto silane coupling agent is added in an amount of 3-6% of the mass of the methyl silicone resin.
  5. 5. The cracking-resistant concrete according to claim 1, wherein the auxiliary gelling component is further added with waste ceramic powder in an amount of 5-8% of the total mass of the steel slag powder and the zeolite powder.
  6. 6. The cracking-resistant concrete according to claim 2, wherein in the step a, the volume fraction of ethanol in the mixed solution of ethanol and water is 30% -50%, and the pH value of mineralization reaction is controlled to be 6.5-7.5.
  7. 7. A crack-resistant concrete according to claim 2, wherein in step b, the phosphorylating agent used for the phosphorylating modification is phosphorus pentoxide.
  8. 8. The process for producing cracking-preventing concrete according to claim 1, comprising the steps of: S1, premixing a cementing material, namely adding silicate cementing components, steel slag powder and zeolite powder into a stirrer, and dry-mixing for 60-90S to form an inorganic cementing system; S2, dispersing functional components, namely adding a composite water reducer, modified magnesium aluminum hydrotalcite and alkali-resistant reinforcing fibers into the inorganic gelling system obtained in the step S1, and continuously dry-mixing for 30-60S to uniformly disperse the functional components; S3, mixing coarse and fine aggregates, namely putting the fine aggregates and the coarse aggregates into a stirrer, and pre-stirring for 30-60S; S4, wet mixing and forming, namely adding mixing water and potassium stearate into the mixer in the step S3, stirring for 90-120S, then injecting concrete mixture into a mould, and vibrating for compaction; and S5, curing, namely curing the formed concrete to obtain the cracking-resistant concrete.

Description

Cracking-resistant concrete and production process thereof Technical Field The invention relates to the technical field of building materials, in particular to cracking-resistant concrete and a production process thereof. Background Concrete is used as a core structural material of modern building engineering, and the performance of the concrete directly determines the safety and durability of the engineering. However, with the increasingly shortage of natural sand resources in recent years, machine-made sand, desalted sea sand and other substitute aggregates are widely applied, sand quality is generally reduced, and the excessive mud content becomes a key bottleneck for restricting the performance of concrete. Although the traditional polycarboxylate water reducer has the advantage of high-efficiency water reduction, carboxyl (-COO -) in the molecular structure is easy to be adsorbed and intercalated by the lamellar structure of clay minerals (such as montmorillonite and illite), so that the water reduction dispersion effect is suddenly reduced, the mixing amount of the water reducer is additionally increased, the construction problems of rapid slump loss, segregation and bleeding of concrete and the like are caused, and the engineering quality and the progress are seriously influenced. At the same time, concrete cracking and insufficient durability remain an industry challenge. On one hand, the slurry workability degradation caused by high mud-containing aggregate is easy to cause plastic shrinkage cracks, and on the other hand, the cracks generated by chloride ion erosion (coastal areas or deicing salt environments), carbonization shrinkage and load action are gradually expanded into macroscopic cracks if not suppressed in time, so that the structural bearing capacity is finally reduced. The traditional anti-cracking technology mostly depends on a single component (such as simply increasing the fiber doping amount or adopting an anti-cracking agent). Chinese patent publication No. CN119349939A discloses a preparation process of heat-resistant anti-cracking concrete, which comprises the following steps of preparing suspension, preparing PVA fiber, modifying PVA fiber by VAE emulsion, and preparing concrete. According to the invention, calcium carbonate whisker and a water reducer are used for preparing suspension, PVA fiber is treated by anatase ore and fly ash, the water reducer can reduce the water demand of materials and improve the fluidity of slurry, so that the PVA fiber and powder are uniformly mixed, anatase stone powder and fly ash can be uniformly distributed in the slurry and then coated on the PVA fiber, and tiny fly ash particles can be mutually attracted, so that the treated PVA fiber can be mutually and tightly combined, and the compression-resistant and anti-cracking performance of the concrete material is improved. However, the process still uses the traditional polycarboxylic acid water reducer, and is easy to be adsorbed by clay to lose efficacy. Chinese patent publication No. CN118405889a discloses an anticracking long-life fiber concrete and a preparation process thereof, so as to solve the problems that the cost of using steel fibers alone or using steel fibers and polyimide fibers in combination is relatively high, it is difficult to uniformly disperse the fibers in the concrete, and part of the defects of the steel fibers cannot be overcome, and at the same time, the steel fibers have a certain stimulation to human respiratory system and skin. The raw materials comprise 176 parts of water, 910 parts of river sand, 726 parts of crushed stone, 356 parts of fly ash silicate cement, 4.6 parts of basalt fiber, 23.5 parts of steel fiber, 18 parts of silica fume, 0.347-1.39 parts of high-efficiency water reducing agent, 10.68-21.36 parts of composite early strength agent, 28.48-42.72 parts of expanding agent and 1.78-14.24 parts of accelerator. The basalt fiber and the steel fiber are matched for use, so that the advantages of high modulus and single high tensile strength of the steel fiber can be exerted, crack expansion is prevented, and the defects of easiness in agglomeration, difficulty in stirring, difficulty in construction, easiness in corrosion, poor durability and high self-weight of the steel fiber are overcome, so that the steel fiber and the steel fiber complement each other. However, the technology still cannot solve the problem of failure of the concrete water reducer in the high-mud-sand-content environment, and cannot achieve the problems of chlorine ion permeation resistance and alkali corrosion resistance. Disclosure of Invention Therefore, aiming at the problems, the invention provides the anti-cracking concrete and the production process thereof, and solves the problems of failure, high cracking risk and insufficient durability of the concrete water reducer in the high mud-sand-containing environment. In order to achieve the above purpose, the present invention adopts