CN-121992698-A - Lightweight hydrophobic antifreeze fly ash-based prefabricated part, preparation method and application

CN121992698ACN 121992698 ACN121992698 ACN 121992698ACN-121992698-A

Abstract

The invention belongs to the technical field of concrete prefabricated parts, and particularly relates to a lightweight hydrophobic antifreeze fly ash-based prefabricated part, a preparation method and application thereof. The base prefabricated part consists of a filling core layer, a matrix layer wrapping the filling core layer, a hydrophobic surface layer wrapping the matrix layer and a reserved hole for plugging, wherein the reserved hole penetrates through the matrix layer and the hydrophobic surface layer on one side, the hydrophobic surface layer is made of stearic acid modified bentonite, cement, mineral powder and water, the water cement ratio of slurry of the hydrophobic surface layer is 0.1-0.3, the matrix layer is made of cement, fly ash, silica fume, stone dust, a water reducing agent and water, the water cement ratio of a mixture of the matrix layer is 0.1-0.3, and the filling core layer is formed by blending one or more of fly ash, red mud and saw mud. The flexural strength and the compressive strength of the prefabricated part are equivalent to those of the cement prefabricated part with the same specification, but the density is greatly reduced, the water absorption is low, the freezing resistance and the salt freezing resistance are greatly improved, and the high-efficiency utilization of solid wastes is realized.

Inventors

FANG MING
LI CHUANHAI
WU SI
GAO GUOHUA
WANG KAI
WANG XINYANG
XU RUIXIN

Assignees

山东高速工程检测有限公司

Dates

Publication Date: 20260508
Application Date: 20260331

Claims (10)

1. A light hydrophobic antifreeze fly ash-based prefabricated part is characterized by comprising a filling core layer, a base layer wrapping the filling core layer, a hydrophobic surface layer wrapping the base layer and a reserved hole for plugging, wherein the reserved hole penetrates through one side of the base layer and the hydrophobic surface layer, the hydrophobic surface layer is prepared from (1-3) of water and (16-20) of stearic acid modified bentonite, (4-6) of cement and mineral powder serving as raw materials of a slurry of the hydrophobic surface layer, the mass ratio of bentonite to stearic acid in the stearic acid modified bentonite is 100 (1-3), the water-cement ratio of the slurry of the hydrophobic surface layer is 0.1-0.3, the base layer is prepared from (45-60) of cement, (50-70) of (3-8) of (25-40) of (0.2-0.4), the water-cement of the mixture of the base layer is 0.1-0.3, and the slurry of the filler core layer is mainly prepared from one or more of the filler sludge.
2. The lightweight hydrophobic freeze-resistant fly ash-based prefabricated part according to claim 1, wherein the filling core layer accounts for 5% -12% of the volume of the prefabricated part.
3. The lightweight hydrophobic freeze-resistant fly ash-based prefabricated part according to claim 1, wherein the thickness ratio of the substrate layer to the hydrophobic surface layer is 4 (1-3).
4. The lightweight hydrophobic freeze-resistant fly ash-based prefabricated part according to claim 1, wherein the water reducing agent is a polycarboxylate water reducing agent.
5. The lightweight hydrophobic freeze-resistant fly ash-based prefabricated part according to claim 1, wherein the fluidity of the matrix layer mixture is not less than 180mm.
6. The lightweight hydrophobic antifreeze fly ash-based prefabricated part according to claim 1, wherein the cement is PI cement with a grade of 52.5, the mineral powder is S95-grade mineral powder, and the reserved holes are plugged and filled by quick-setting cement.
7. A method for preparing a lightweight hydrophobic antifreeze fly ash based prefabricated part as defined in any one of claims 1 to 6, comprising the steps of: mixing bentonite with stearic acid, reacting at 75-90 ℃ for 1-3 hours, and then ball milling until the average particle size is less than or equal to 10 mu m to obtain stearic acid modified bentonite; mixing cement, mineral powder, stearic acid modified bentonite and water to prepare fabric premix, adding the fabric premix into a colloid mill, shearing the fabric premix to prepare fabric premix, carrying out filter pressing treatment on the fabric premix by adopting a filter pressing device, and separating redundant free water to prepare the hydrophobic surface layer slurry; mixing cement, fly ash, stone dust, silica fume, a water reducing agent and water to prepare a matrix layer mixture; And preparing the filling core layer material by taking the raw materials required by filling the core layer.
8. The method for preparing a lightweight hydrophobic antifreeze fly ash based prefabricated part according to claim 7, further comprising the steps of: Preparing a prefabricated part: Constructing a mould, firstly pouring hydrophobic surface layer slurry outside the top layer hydrophobic surface layer according to the structure of the prefabricated part, and extruding the hydrophobic surface layer slurry to form a hydrophobic surface layer frame in the mould; Placing a polycaprolactone block matched with the size of the filling core layer after pouring the bottom matrix layer mixture, placing a hole die matched with the reserved hole above the polycaprolactone block, finishing pouring of the matrix layer mixture, compacting the matrix layer by adopting a standard vibrating table for vibration molding; heating, steam curing for 6-12 h under the condition that the relative humidity is more than or equal to 95%, turning over the die, drawing out the hole die, pouring out the melted polycaprolactone, filling the filling core layer material through the reserved holes, plugging and filling the reserved holes, and performing conventional curing for 20-40 days.
9. The preparation method of the lightweight hydrophobic antifreeze fly ash-based prefabricated part, which is disclosed in claim 8, is characterized in that the steam curing temperature is 50-70 ℃, the conventional curing condition is 20-23 ℃, and the relative humidity is more than or equal to 90%.
10. Use of a lightweight hydrophobic antifreeze fly ash based prefabricated part according to claim 1 or obtained by the method of preparation according to claim 7 as a curb.

Description

Lightweight hydrophobic antifreeze fly ash-based prefabricated part, preparation method and application Technical Field The invention belongs to the technical field of concrete prefabricated parts, and particularly relates to a lightweight hydrophobic antifreeze fly ash-based prefabricated part, a preparation method and application thereof. Background The traditional concrete prefabricated part has two defects of large self-weight (the density is more than or equal to 2400 kg/m < 3 >) and low solid waste absorbing capacity. On one hand, the high density increases the energy consumption of transportation and installation by more than 30 percent, thereby remarkably increasing the engineering cost, and on the other hand, the industrial solid waste amount of fly ash, red mud and the like is extremely large in China each year, but the solid waste mixing amount in the existing components is generally extremely low, and a large amount of stockpiling occupies land and causes heavy metal infiltration pollution. And when the mixing amount of the fly ash is too high, the active component is insufficient, the porosity is increased, the compressive strength is suddenly reduced, the high-strength requirement of more than 50MPa can not be met, and the solid waste recycling process is severely restricted. In addition, the water absorption rate of the concrete member is generally higher than 5%, the water is easy to invade under the action of freeze thawing cycle to cause internal crystallization pressure, and the mass loss rate after 300 times of freeze thawing can reach 3% -5%, which is far higher than the national standard limit value (less than or equal to 1.5%). While the traditional technical route tries to realize light weight by adding lightweight aggregate, strength reduction (35% -50% of reduction amplitude) is caused by thin weakening of an aggregate-slurry interface, according to some existing researches (CN 108892451A, CN 112723844A), density reduction is realized by adding porous ceramic, high-strength lightweight fiber and other materials, the performance of the materials is not reduced, but the production cost is greatly increased, and the technical dilemma of 'light weight must be low in strength and high in cost' is formed. The technical barriers in the deep layer are that the strong hydrophilicity (contact angle <90 ℃) of mineral admixture such as material layer, bentonite and the like is contrary to the waterproof requirement, the conventional hydrophobic modification is easy to damage the cement hydration process, and the structural layer is that the solid waste filling core material is easy to cause component cracking due to poor volume stability (drying shrinkage rate is more than 0.08%). While the prior researches try to improve the performance through fiber reinforcement or chemical foaming, the synergistic development of light weight, high strength and hydrophobicity is difficult to achieve. Disclosure of Invention Aiming at the problems, the invention aims to provide a lightweight hydrophobic fly ash-based prefabricated part, a preparation method and application thereof. The technical scheme of the invention comprises the following steps: The lightweight hydrophobic antifreeze fly ash-based prefabricated part comprises a filling core layer, a substrate layer wrapping the filling core layer, a hydrophobic surface layer wrapping the substrate layer and a reserved hole for plugging, wherein the reserved hole penetrates through one side of the substrate layer and the hydrophobic surface layer, the hydrophobic surface layer is prepared from raw materials of a substrate layer slurry, wherein the raw materials comprise (1-3) of water, (16-20) of stearic acid modified bentonite, (4-6) of cement and mineral powder, the mass ratio of bentonite to stearic acid in the stearic acid modified bentonite is 100 (1-3), the water-cement ratio of the substrate layer slurry is 0.1-0.3, the substrate layer is prepared from raw materials of a substrate layer mixture, the raw materials comprise (0.2-0.4) of cement, fly ash, silica fume, stone dust and a water reducing agent, the water-cement ratio of the substrate layer slurry is 45-60, the substrate layer slurry is 50-70), and the substrate layer mixture mainly comprises one or more of the following materials of the filler mud. The filling core layer is used for containing solid waste materials, improving the recycling rate of the solid waste materials, reducing the density of the prefabricated parts, improving the light weight degree of the prefabricated parts, ensuring the performances of moisture resistance, frost resistance and the like of the prefabricated parts and the hardness of the matrix layer and the hydrophobic surface layer, and reducing the influence on the cement hydration reaction of the concrete materials. The term "consisting essentially of" a material or materials, means that there may be unavoidable some residual mold components, such as polycaprolac