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CN-122010495-A - Concrete resistant to dry and wet cycle and preparation method thereof

CN122010495ACN 122010495 ACN122010495 ACN 122010495ACN-122010495-A

Abstract

The invention relates to the technical field of building materials, and discloses concrete resistant to dry and wet circulation and a preparation method thereof. The concrete is prepared from 500-900 parts of cementing material, 1000-1600 parts of sand and 225-360 parts of water, wherein the cementing material comprises 125-675 parts of cement and 125-675 parts of beta-C 2 S. The preparation method comprises mixing cement, beta-C 2 S and sand, adding water, stirring to obtain slurry, molding, demolding, and maintaining with CO 2 . According to the invention, the beta-C 2 S is used for partially replacing cement and combining with a specific CO 2 curing process, so that the harmful expansion of concrete in a dry-wet circulating environment is obviously reduced, the volume stability and long-term durability are improved, and the carbon fixation and emission reduction are realized.

Inventors

  • HE PINGPING
  • HUANG SHUMIN
  • YAN FEIFEI
  • ZHU XUANMIN
  • PENG SIRUI
  • YANG ZIHAN
  • LIU PENGHUI
  • ZENG CHENG

Assignees

  • 长沙理工大学

Dates

Publication Date
20260512
Application Date
20260213

Claims (8)

  1. 1. The concrete resistant to dry and wet circulation is characterized by being prepared from the following raw materials in parts by weight: 500-900 parts of cementing material; 1000-1600 parts of sand; 225-360 parts of water; The cementing material comprises 125-675 parts of cement and 125-675 parts of beta-C 2 S, wherein the proportion of the beta-C 2 S to the total weight of the cementing material is 25-75wt%.
  2. 2. The dry and wet cycle resistant concrete of claim 1 wherein the cement is Portland cement.
  3. 3. A method for preparing concrete resistant to the dry and wet cycle according to any one of claims 1 to 2, comprising the steps of: S1, uniformly mixing cement, beta-C 2 S and sand; s2, adding water, and uniformly stirring to obtain concrete slurry; s3, molding and demolding the concrete slurry to obtain a concrete test piece; And S4, carrying out CO 2 curing on the concrete test piece.
  4. 4. A method of preparing concrete resistant to dry and wet cycles according to claim 3, characterized in that said CO 2 curing is carried out under pressure of 0.15MPa to 0.25 MPa.
  5. 5. The method for preparing concrete resistant to dry and wet cycle according to claim 3, wherein the curing conditions of CO 2 further comprise a humidity of 55-65% and a curing time of 2-4 hours.
  6. 6. The method for preparing dry and wet cycle resistant concrete according to claim 3, further comprising the step of drying the demolded specimen until the water-cement ratio is not higher than 0.3 before curing with CO 2 .
  7. 7. A method for preparing concrete resistant to dry and wet cycles as claimed in claim 3, wherein in step S2, the water-cement ratio is 0.45.
  8. 8. A method of preparing concrete resistant to dry and wet cycles as claimed in claim 3, wherein the mixing is carried out with a high speed mixer for a period of 3 minutes.

Description

Concrete resistant to dry and wet cycle and preparation method thereof Technical Field The invention relates to the technical field of building materials, in particular to a concrete material suitable for a dry-wet circulation environment and a preparation method thereof, and especially relates to concrete with improved volume stability through composition optimization and a CO 2 curing process. Background The CO 2 curing concrete technology can effectively cure CO 2 discharged by industry and improve early performance of concrete, and is a low-carbon building material technology with prospect. However, after curing the conventional Portland cement with CO 2, a large amount of silica gel with high polymerization degree and high specific surface area is produced. The silica gel repeatedly absorbs water and dehydrates in a dry-wet circulation environment, generates obvious expansion and contraction stress, is easy to crack concrete for a long time, damages the durability of the concrete, and limits the application of CO 2 curing concrete in a complex environment. In the prior art, in order to improve the performance of concrete, a method of adding various special admixtures, fibers or complex chemical additives is often adopted, but the problems of high cost, complex process and the like exist. Therefore, development of a technical scheme which is simple in raw materials, controllable in cost and capable of fundamentally improving the dry and wet cycle resistance of CO 2 cured concrete is needed. Disclosure of Invention Aiming at the problems of poor volume stability and easiness in expansion and cracking of the existing CO 2 cured concrete under the dry and wet cycle, the invention aims to provide the concrete for resisting the dry and wet cycle and the preparation method thereof. According to the scheme, through the cooperation of material composition design and maintenance technology, harmful expansion is effectively restrained, and long-term durability is improved. In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect, the invention provides concrete resistant to dry and wet cycles, which is prepared from the following raw materials in parts by weight: 500-900 parts of cementing material; 1000-1600 parts of sand; 225-360 parts of water; Wherein the cementing material comprises 125-675 parts of cement and 125-675 parts of beta-C 2 S. Preferably, the cement is Portland cement. In a second aspect, the invention provides a method for preparing the concrete with the dry and wet cycle resistance, which comprises the following steps: S1, uniformly mixing cement, beta-C 2 S and sand; s2, adding water, and uniformly stirring to obtain concrete slurry; s3, molding and demolding the concrete slurry to obtain a concrete test piece; And S4, carrying out CO 2 curing on the concrete test piece. Preferably, the CO 2 curing is performed at a pressure of 0.15MPa to 0.25 MPa. Preferably, the curing condition of the CO 2 also comprises that the humidity is 55-65%, and the curing time is 2-4 hours. Preferably, before the curing of the CO 2, the method further comprises the step of drying and pre-treating the demoulded test piece until the water-cement ratio is not higher than 0.3. Preferably, in step S2, the water to ash ratio is 0.45. Preferably, the mixing is carried out using a high speed stirrer for a period of 3 minutes. The invention has the beneficial effects that: (1) The invention changes the microstructure of the CO 2 curing product fundamentally by introducing beta-C 2 S to replace cement partially. The incorporation of β -C 2 S significantly reduces the degree of polymerization of the siliceous phase, allowing it to form a low degree of polymerization phase that more closely approximates a stable C-S-H gel, rather than a highly swellable, high degree of polymerization silica gel. Meanwhile, the addition of beta-C 2 S changes the pore structure of the material, increases the porosity and optimizes the pore size distribution, and provides a physical buffer space for potential volume change. The synergistic optimization of the chemical structure and the physical structure is a core mechanism which can effectively inhibit the harmful expansion of the material under the dry-wet cycle, thereby obtaining the performance of 'dry-wet cycle resistance'. (2) The beta-C 2 S is a low-carbon gelling material, and the carbon emission of raw materials is directly reduced by replacing cement in a large amount. And the curing of greenhouse gases is realized by combining a CO 2 curing process, and double carbon reduction is realized. Meanwhile, the raw materials are simple, expensive additives are not needed, the process is easy to control, and the production cost and the full life cycle maintenance cost are reduced. Drawings For a clearer description of the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the e