CN116573902A - A kind of liquid cementitious material and concrete preparation method - Google Patents

Abstract

The invention discloses a liquid cementing material and a preparation method of concrete. The hydraulic cementing material is hydrated in advance at normal temperature and normal pressure, a hydroxide neutralizing substance is added into a system after hydration, then the reaction temperature and the reaction pressure are increased, and a mechanochemical strengthening reaction is carried out, so that the liquid cementing material is formed after the reaction is finished. The liquid gel material is used for producing various solid gel materials, improves the early strength of the material, improves the volume stability of the material, and does not influence the later strength and the durability of the material.

Description

A kind of liquid cementitious material and concrete preparation method

technical field

The invention belongs to the technical field of hydraulic cementitious materials, and in particular relates to a liquid cementitious material and a related concrete preparation method.

Background technique

Traditional hydraulic gelling materials are hydrated to form silica-calcium gel, silica-alumina gel, etc., and hydroxides, and hydroxides seriously affect the early strength of materials. The commonly used method is to neutralize calcium hydroxide by adding volcanic ash. Due to the long reaction time and slow reaction speed, it can only improve the later strength of the material, and the early strength is still low; the second is to add various chemical early strength agents to promote Although the hydration reaction and chemical additives improve the early strength of the material, the chemical early strength agent brings harm to the later strength.

Contents of the invention

Aiming at the defects or deficiencies of the prior art, the present invention provides a preparation method of liquid gelling material.

For this reason, the liquid gelling material preparation method provided by the present invention comprises: under normal temperature and pressure, the hydraulic gelling material with a strength greater than or equal to 32.5Mpa and water are mixed according to the mass ratio of 1: (2-3), and the hydration reaction After 9 to 12 hours, add neutralizing substances and mix well, then carry out chemical reaction at 50°C-90°C and 0.1-1Mpa for 1-4 hours, and then cool to room temperature to obtain liquid gelling material;

The chemical reaction is carried out in the presence of ultrasonic waves, stirring or vibration;

The hydraulic cementitious material is selected from Portland cement, sulfate cement, sulfoaluminate cement or aluminate cement; Portland cement is preferred;

The neutralizer is selected from organic acids and inorganic acidic substances such as nano silicon oxide, citric acid, gluconic acid and polycarboxylic acid. Nano silicon oxide is preferred.

An optional solution is that the added molar amount of the neutralizing substance is the same as the molar amount of the hydroxide generated by the hydration reaction.

The invention also provides related concrete. The concrete is prepared from cement, fly ash, sand, aggregate, water reducing agent and the liquid gelling material prepared by the above method. Further, the concrete preparation raw material also includes mineral powder.

The present invention provides the preparation method of relevant concrete simultaneously, and the preparation method provided comprises:

Step 1. Using cement, fly ash, sand, aggregates and admixtures as raw materials, design the concrete formula to obtain the initial formula;

Step 2, increase the amount of fly ash and reduce the amount of cement on the basis of the initial formula, and add the liquid cementitious material prepared by the above method accounting for 2%-5% of the total mass of the material, and the solid content of the liquid cementitious material is 20% to 30%;

Step 3, preparing concrete according to the formula designed in step 2.

An optional solution is that the increase in the quality of the fly ash is the same as the reduction in the quality of the cement.

The preparation method of another kind of related concrete provided by the invention comprises:

Step 1, using cement, fly ash, sand, aggregate, mineral powder and admixtures as raw materials, design the concrete formula to obtain the initial formula;

Step 2, increase the amount of fly ash and mineral powder on the basis of the initial formula, and reduce the amount of cement, while adding the liquid cementitious material prepared by the method described in claim 1 accounting for 2%-5% of the total mass of the material, and the The solid content of the liquid gelling material is 20% to 30%;

Step 3, preparing concrete according to the formula designed in step 2.

An optional solution is that increasing the total mass of fly ash and mineral powder is the same as reducing the mass of cement.

An optional solution is that the hydraulic cementitious material used in the preparation of the liquid cementitious material described in step 2 in the above preparation method is the same as the cement used in step 1.

In the present invention, the hydraulic gelling material is hydrated at normal temperature and pressure. After hydration, a substance that neutralizes hydroxide is added to the system, and then the reaction temperature and pressure are increased, and the mechanochemical strengthening reaction is carried out. Liquid gelling material. The liquid gel material of the present invention is used for the production of various solid gelling materials, while improving the early strength of the material (before 28 days), the volume stability of the material is improved without affecting the later strength of the material (the strength after 28 days) strength) and material durability.

Detailed ways

Unless otherwise defined, scientific and technical terms used herein are to be understood according to the understanding of those of ordinary skill in the relevant art.

The raw materials for the preparation of concrete according to the present invention add the liquid gelling material of the present invention on the basis of the existing concrete preparation raw materials, and add an appropriate amount of the liquid gelling material of the present invention after adjusting the components in the initial formula based on the initial formula in formula design Material. The initial formula is the formula obtained by adopting the existing concrete formula design method. When preparing the concrete of the present invention, the order of adding the materials follows the principle of the order of adding the existing concrete materials. In particular, the liquid gelling material can be selected to be added simultaneously with water or successively with water.

The following are specific examples of the present invention. It should be noted that specific reaction conditions such as concrete strength, material ratio, replacement amount of related substances in the formula, processing temperature, and pressure involved in the following examples are intended to explain the present invention , on the basis of the disclosure herein, those skilled in the art can optimize and select the above-mentioned related factors and conditions to achieve the purpose of the present invention and obtain other specific implementation examples of the present invention.

For the formula design of the reference samples in the following examples, refer to the existing "Ordinary Concrete Mix Proportion Design Regulations" JGJ55-2011. For the performance tests of concrete in the following examples, refer to "Test Methods for Mechanical Properties of Ordinary Concrete" GB/T50081-2002; "Test Methods for Performance of Ordinary Concrete Mixtures" GB/T50080-2002.

Example 1:

Preparation of the liquid cementitious material in this example: mix 10kg of P.O 42.5 cement with 30kg of water, after hydration reaction for 10 hours, add 2kg of nano-silicon oxide as a hydroxide neutralizing agent, mix it under ultrasonic wave, 0.3Mpa and 60°C The reaction was carried out under conditions for 2 hours, and then cooled to room temperature. The solid content of the liquid cementitious material prepared in this embodiment was diluted to 25% for preparing concrete.

Further use the solid content of this embodiment as 25% liquid cementitious material to prepare C30 concrete; except the liquid cementitious material, all the other raw materials are: P.O 42.5 cement, secondary fly ash, sand in river sand, broken gravel and aggregate Carboxylic acid water reducer, this embodiment designs three groups of concrete samples:

Benchmark sample formula: cement: fly ash: sand: stone: water: water reducer = 295: 70: 790: 1020: 175: 11; the mixing method is: after the solid material is added to the concrete mixer, the mixing process is slow Add water and mix well;

Trial mix 1: On the basis of the formula of the benchmark sample in this example, add fly ash and liquid cementitious material to reduce the amount of cement; the specific liquid cementitious material content is 3% of the total mass of all raw materials, fly ash, etc. Replace 30kg of cement; the mixing method is: after the solid material is added to the concrete mixer, slowly add water and liquid cementitious material and mix evenly during the mixing process;

Trial mix 2: On the basis of the formula of the benchmark sample in this example, add fly ash and liquid cementitious material to reduce the amount of cement; the specific liquid cementitious material content is 5% of the total mass of all raw materials, fly ash, etc. Replace 50kg of cement; the mixing method is: add solid materials into the mixer, and slowly add water and liquid cementitious materials during the mixing process;

The test results of each group of samples are shown in Table 1-2.

Table 1 Work performance test value

Table 2 concrete strength test value

Example 2:

The difference between this example and Example 1 is that the remaining concrete raw materials are: P.O 42.5 cement, secondary mineral powder, secondary fly ash, sand in river sand, broken gravel, polycarboxylate superplasticizer; three groups of samples for:

Benchmark sample formula: cement: mineral powder: fly ash: sand: stone: water: water reducing agent = 170: 100: 50: 1005: 840: 154: 15;

Trial mix 1: On the basis of the standard sample formula of this embodiment, add fly ash and liquid cementitious material to reduce the amount of cement; the amount of liquid cementitious material is 3% of the total mass of all raw materials, 30kg flyash and 20kg Mineral powder replaces 50kg cement;

Trial mix 2: On the basis of the formula of the benchmark sample in this embodiment, add fly ash and liquid cementitious material to reduce the amount of cement; the amount of liquid cementitious material is 5% of the total mass of all raw materials, 30kg flyash and 20kg Mineral powder replaces 50kg of cement.

The test results of each group of samples in this embodiment are shown in Table 3-4.

Table 3 Work performance test value

Table 4 concrete strength test value

Example 3:

The difference between this embodiment and embodiment 1 is that the remaining concrete raw materials are: P.O 42.5 cement, third-grade fly ash, artificial machine-made sand, crushed gravel and polycarboxylate superplasticizer. The two sets of samples designed are:

Benchmark: cement: fly ash: sand: stone: water: water reducing agent = 260: 80: 821: 1090: 180: 12;

Trial mix 1: On the basis of the formula of the reference sample of this embodiment, add fly ash and liquid cementitious material to reduce the amount of cement; the amount of liquid cementitious material prepared in Example 1 is 3% of the total mass of raw materials used, and The same amount of coal ash replaces 40kg of cement;

The test results of each group of samples in this embodiment are shown in Table 5-6.

Table 5 Work performance test value

Table 6 concrete strength test value

Example 4:

The difference between this example and Example 1 is that the remaining raw materials are: P.O 42.5 cement, secondary fly ash, stone powder, sand in river sand, broken gravel and polycarboxylate superplasticizer. The two sets of samples set are:

Benchmark sample: cement: fly ash: stone powder: sand: stone: water: water reducing agent = 240: 100: 356: 563: 1000: 150: 8.5;

Trial mix 1: On the basis of the formula of the benchmark sample in this example, add fly ash and liquid cementitious material to reduce the amount of cement; the specific liquid cementitious material content is 3% of the total mass of all raw materials, fly ash, etc. amount to replace 40kg of cement.

The test results of each group of samples in this embodiment are shown in Table 7-8.

Table 7 Work performance test value

Table 8 concrete strength test value

Example 5:

The difference between this embodiment and Example 1 is that the remaining raw materials used in this embodiment are: P.O 42.5 cement, secondary fly ash, stone powder, sand in river sand, broken gravel and polycarboxylate water reducer; The group samples are:

Benchmark sample: cement: fly ash: stone powder: sand: stone: water: water reducing agent = 265: 40: 600: 390: 950: 135: 10.0;

Trial mix 1: On the basis of the formula of the reference sample of this embodiment, add fly ash and liquid cementitious material (the liquid cementitious material prepared in Example 1 after storage for 20 days), reduce the amount of cement; the specific liquid cementitious material The dosage is 3% of the total mass of all raw materials, and the same amount of fly ash replaces 30kg of cement;

Trial mix 2: On the basis of the formula of the benchmark sample in this example, add fly ash and liquid cementitious material to reduce the amount of cement; the specific liquid cementitious material content is 5% of the total mass of all raw materials, fly ash, etc. amount to replace 40kg of cement.

Each sample test result of this embodiment is shown in Table 9-10.

Table 9 Work performance test value

Table 10 concrete strength test value

Embodiment 6:

This embodiment differs from embodiment 1 in that the three groups of samples provided are:

Benchmark sample: cement: fly ash: sand: stone: water: admixture = 280: 95: 865: 980: 160: 9.4;

Trial mix 1: On the basis of the formula of the benchmark sample in this example, add fly ash and liquid cementitious material to reduce the amount of cement; the specific liquid cementitious material content is 3% of the total mass of all raw materials, fly ash, etc. Quantity to replace 36kg cement;

Trial mix 2: On the basis of the formula of the reference sample in this embodiment, add fly ash and liquid cementitious material to reduce the amount of cement; the specific liquid cementitious material content is 3% of the total mass of all raw materials, fly ash, etc. Quantity to replace 54kg cement;

The test results of each group of samples in this embodiment are shown in Table 11-12.

Table 11 Work performance test value

Table 12 concrete strength test value

Claims (9)

1. A method for preparing a liquid cementing material, which is characterized by comprising the following steps: mixing a hydraulic cementing material with the strength of more than or equal to 32.5Mpa and water according to the mass ratio of 1 (2-3), adding a neutralizing substance after hydration reaction for 9-12 hours, uniformly mixing, then carrying out chemical reaction for 1-4 hours at 50-90 ℃ and 0.1-1Mpa, and cooling to the room temperature to obtain the liquid cementing material;

the chemical reaction is carried out in the presence of ultrasonic waves, stirring or vibration;

the hydraulic cementing material is selected from silicate cement, sulfate cement, sulphoaluminate cement or aluminate cement;

the neutralization substance is selected from organic acid and inorganic acidic substances such as nano silicon oxide, citric acid, gluconic acid, polycarboxylic acid and the like.

2. The method for preparing a liquid cement according to claim 1, wherein the amount of the neutralizing substance added is the same as the amount of the hydroxide produced by the hydration reaction.

3. The concrete is characterized in that the concrete is prepared from cement, fly ash, sand, aggregate, a water reducing agent and the liquid cementing material prepared by the method of claim 1.

4. A concrete according to claim 3, wherein the concrete preparation raw material further comprises mineral powder.

5. A method of preparing concrete, the method comprising:

step 1, designing a concrete formula by taking cement, fly ash, sand, aggregate and an additive as raw materials to obtain an initial formula;

step 2, increasing the consumption of fly ash and reducing the consumption of cement on the basis of an initial formula, and adding the liquid cementing material which accounts for 2-5% of the total mass of the materials and is prepared by the method of claim 1, wherein the solid content of the liquid cementing material is 20-30%;

and 3, preparing concrete according to the formula designed in the step 2.

6. The method of preparing concrete according to claim 4, wherein the increasing the mass of fly ash is the same as the decreasing the mass of cement.

7. The method for preparing concrete according to claim 5, wherein the method comprises:

step 1, designing a concrete formula by taking cement, fly ash, sand, aggregate, mineral powder and an additive as raw materials to obtain an initial formula;

step 2, increasing the consumption of fly ash and mineral powder on the basis of an initial formula, reducing the consumption of cement, and simultaneously adding the liquid cementing material which accounts for 2-5% of the total mass of the materials and is prepared by the method of claim 1, wherein the solid content of the liquid cementing material is 20-30%;

and 3, preparing concrete according to the formula designed in the step 2.

8. The method of producing concrete according to claim 7, wherein the increase in the total mass of fly ash and mineral powder is the same as the decrease in the mass of cement.

9. The method according to claim 4 or 7, wherein the liquid cement in step 2 is prepared by using the hydraulic cement in the same manner as the cement in step 1.