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CN-121609545-B - High-strength low-carbon composite cementing material based on gradient pouring and preparation method thereof

CN121609545BCN 121609545 BCN121609545 BCN 121609545BCN-121609545-B

Abstract

The invention discloses a high-strength low-carbon composite cementing material based on gradient pouring and a preparation method thereof, wherein the composite cementing material comprises an alkali-activated cementing material layer and a cement-based cementing material layer from inside to outside, and the alkali-activated cementing material layer and the cement-based cementing material layer are combined into a whole through gradient pouring; the raw materials of the alkali-activated cementing material layer comprise granulated blast furnace slag, coal gangue powder, alkali-activated agent, aggregate and water, and the raw materials of the cement-based cementing material layer comprise Portland cement, aggregate and water. According to the invention, the alkali-activated cementing material taking granulated blast furnace slag and gangue powder as solid raw materials and the cement-based cementing material taking silicate cement as solid raw materials are combined into a whole in a gradient pouring mode, so that the composite cementing material is obtained, the strength performance of the composite cementing material is substantially improved on the basis of retaining the advantages of early strength and low carbon of the alkali-activated slag, and the carbonization resistance is also obviously improved.

Inventors

  • CUI YULONG
  • HUANG GUODONG
  • MA XIURU

Assignees

  • 安徽理工大学

Dates

Publication Date
20260508
Application Date
20260202

Claims (7)

  1. 1. The high-strength low-carbon composite cementing material based on gradient pouring is characterized by comprising an alkali-activated cementing material layer and a cement-based cementing material layer from inside to outside, wherein the alkali-activated cementing material layer and the cement-based cementing material layer are combined into a whole through gradient pouring; the raw materials of the alkali-activated cementing material layer comprise granulated blast furnace slag, coal gangue powder, alkali-activated agent, aggregate and water, and the raw materials of the cement-based cementing material layer comprise Portland cement, aggregate and water; The mass ratio of the silicate cement to the aggregate to the water is 1 (2-4) (0.4-0.6), and the mass ratio of the granulated blast furnace slag to the gangue powder to the alkali-activated agent to the river sand to the water is 1 (0.9-1.1) (0.5-0.7) (5-7) (0.4-0.6); the weight percentage of the alkali-activated cementing material layer relative to the total amount of the composite cementing material is 5-95%, and the weight percentage of the cement-based cementing material layer relative to the total amount of the composite cementing material is 95-5%; the coal gangue powder is activated coal gangue powder, and is obtained by grinding the coal gangue powder by adopting a grinding aid, wherein the grinding aid is obtained by carrying out addition reaction on polyvinylpyrrolidone and ethylenediamine, and then carrying out phosphonation reaction on the polyvinylpyrrolidone and formaldehyde; The preparation method of the high-strength low-carbon composite cementing material based on gradient pouring comprises the steps of mixing raw materials in an alkali-activated base cementing material layer, pouring and solidifying the raw materials added with a cement-based cementing material layer, and obtaining the high-strength low-carbon composite cementing material.
  2. 2. The gradient pouring-based high-strength low-carbon composite cementing material according to claim 1, wherein the Portland cement is P.O 42.5.5, 42.5R, 52.5 or 52.5R ordinary Portland cement, and the specific surface area is more than or equal to 400m2/kg; The chemical composition of the material in mass percent is as follows ：CaO 60-65%,SiO 2 20-25%,Al 2 O 3 5-10%,Fe 2 O 3 1-5%,MgO 0-1%,Na 2 O 0-1%,K 2 O 0-1%.
  3. 3. The gradient pouring-based high-strength low-carbon composite cementing material according to claim 1 or 2, wherein the aggregate is river sand and the fineness modulus is 1.6-2.2.
  4. 4. The gradient pouring-based high-strength low-carbon composite cementing material according to claim 1 or 2, wherein the granulated blast furnace slag is S75, S95 or S105 grade slag powder, and the specific surface area is more than or equal to 400m 2 /kg; the chemical composition of the material in mass percent is as follows ：CaO 35-40%,SiO 2 30-35%,Al 2 O 3 15-20%,Fe 2 O 3 1-5%,MgO 1-5%,Na 2 O 0-1%,K 2 O 0-1%.
  5. 5. The gradient pouring-based high-strength low-carbon composite cementing material according to claim 1 or 2, wherein the specific surface area of the gangue powder is more than or equal to 400m 2 /kg; the chemical composition of the material in mass percent is as follows ：SiO 2 65-70%,Al 2 O 3 20-25%,Fe 2 O 3 1-5%,CaO 1-5%,K 2 O 1-5%,MgO 0-1%,Na 2 O 0-1%.
  6. 6. The gradient casting-based high-strength low-carbon composite cementitious material according to claim 1 or 2, wherein the alkali-activator comprises sodium hydroxide and liquid sodium silicate; the mass ratio of the sodium hydroxide to the liquid sodium silicate is 1 (4-6); The liquid sodium silicate comprises, by mass, 60-65% of Na 2 O 5-10%,Si 2 O 25-30%,H 2 O.
  7. 7. The gradient casting-based high-strength low-carbon composite cementing material according to claim 1, wherein the initial setting time is 10-30min.

Description

High-strength low-carbon composite cementing material based on gradient pouring and preparation method thereof Technical Field The invention belongs to the technical field of engineering materials, and particularly relates to a high-strength low-carbon composite cementing material based on gradient pouring and a preparation method thereof. Background Cement (PC) has advantages of high compressive strength, excellent durability, etc., but has problems of high energy consumption and high carbon emission in the production process. The alkali-activated slag (AAS) takes industrial solid waste as a main raw material, forms aluminosilicate gel at normal temperature through alkali excitation, can reduce carbon emission by 60-80% compared with PC, has the characteristics of prominent early strength and chemical erosion resistance, and the like, and is regarded as a green gelling material with great potential in the 21 st century. However, AAS still faces significant challenges in terms of popularization and application. The alkali excitant (such as NaOH and water glass) has higher cost and limits the economic feasibility, meanwhile, the high alkali environment brings construction safety risk and is easy to burn operators, and most importantly, the AAS has poor carbonization resistance and volume stability, large drying shrinkage and obviously inferior long-term durability to PC. It is difficult to combine low carbon and high performance requirements by relying on PC or AAS alone, so the combination of the two is regarded as a promising technological route. The AAS is used for realizing early strength, low carbon and solid waste recycling, and the PC is used for optimizing the alkali environment, improving carbonization resistance and contractility, and realizing performance complementation and synergistic enhancement. Disclosure of Invention Based on the technical problems, the invention provides the high-strength low-carbon composite cementing material based on gradient pouring and the preparation method thereof, wherein the alkali-activated cementing material taking granulated blast furnace slag and gangue powder as solid raw materials and the cement-based cementing material taking silicate cement as solid raw materials are combined into a whole in a gradient pouring mode to obtain the composite cementing material, so that the strength performance of the composite cementing material is substantially improved on the basis of keeping the advantages of early strength and low carbon of alkali-activated slag, and the carbonization resistance is also obviously improved. The invention provides a high-strength low-carbon composite cementing material based on gradient pouring, which comprises an alkali-activated cementing material layer and a cement-based cementing material layer from inside to outside, wherein the alkali-activated cementing material layer and the cement-based cementing material layer are combined into a whole through gradient pouring; the raw materials of the alkali-activated cementing material layer comprise granulated blast furnace slag, coal gangue powder, alkali-activated agent, aggregate and water, and the raw materials of the cement-based cementing material layer comprise Portland cement, aggregate and water. In the invention, in order to solve the difficult problems of high energy consumption and high emission of cement, the key scientific problem of incompatibility of the two compounds is solved by utilizing the low carbon potential of alkali slag, a composite gel suitable for gradient pouring is provided, the influence rule of material composition design and a composite mode on polycondensation and hydration reaction competing mechanism is researched, and a multi-scale coupling structure-effect regulation mechanism is disclosed. Preferably, the mass ratio of the silicate cement, the aggregate and the water is 1 (2-4) (0.4-0.6), preferably 1:3:0.5, and the mass ratio of the granulated blast furnace slag, the gangue powder, the alkali-activated agent, the river sand and the water is 1 (0.9-1.1) (0.5-0.7) (5-7) (0.4-0.6), preferably 1:1:0.6:6:0.5; Preferably, the alkali-activated matrix gel material layer accounts for 50-95wt% of the total amount of the composite gel material, and the cement-based gel material layer accounts for 5-50wt% of the total amount of the composite gel material. Preferably, the Portland cement is P.O 42.5, 42.5R, 52.5 or 52.5R Portland cement, and the specific surface area is more than or equal to 400m2/kg; The chemical composition of the material in mass percent is as follows ：CaO 60-65%,SiO2 20-25%,Al2O3 5-10%,Fe2O3 1-5%,MgO 0-1%,Na2O 0-1%,K2O 0-1%. Preferably, the aggregate is river sand, and the fineness modulus is 1.6-2.2. Preferably, the granulated blast furnace slag is S75, S95 or S105 grade slag powder, and the specific surface area is more than or equal to 400m2/kg; the chemical composition of the material in mass percent is as follows ：CaO 35-40%,SiO2 30-35%,Al2O3