Liquid cementitious material and concrete preparation method

Abstract

This invention discloses a method for preparing a liquid cementitious material and concrete. The method involves pre-hydrating a hydraulic cementitious material at room temperature and pressure. After hydration, a substance to neutralize hydroxides is added to the system. The reaction temperature and pressure are then increased to induce a mechanochemical strengthening reaction, resulting in a liquid cementitious material. This liquid gel material can be used in the production of various solid cementitious materials, improving both early-stage strength and volume stability without affecting later-stage strength and durability.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic cementitious materials, and in particular relates to a liquid cementitious material and a method for preparing related concrete. Background Art

[0002] Traditional hydraulic cementitious materials are hydrated to generate calcium silicate gel, aluminum silicate gel and hydroxide, and hydroxide seriously affects the early strength of the material. 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 method is to promote the hydration reaction by adding various chemical early strength agents. Although chemical additives improve the early strength of the material, chemical early strength agents harm the later strength. Summary of the invention

[0003] In view of the defects or shortcomings of the prior art, the present invention provides a method for preparing a liquid gelling material.

[0004] To this end, the preparation method of the liquid gelling material provided by the present invention comprises: mixing a hydraulic gelling material having a strength greater than or equal to 32.5 MPa and water in a mass ratio of 1:(2-3) at room temperature and pressure, adding a neutralizing substance after hydration reaction for 9 to 12 hours and mixing, then performing a chemical reaction at 50° C. to 90° C. and 0.1 to 1 MPa for 1 to 4 hours, and then cooling to room temperature to obtain a liquid gelling material;

[0005] The chemical reaction is carried out under the condition of ultrasound, stirring or vibration;

[0006] The hydraulic cementitious material is selected from silicate cement, sulfate cement, sulphoaluminate cement or aluminate cement; preferably silicate cement;

[0007] The neutralizer is selected from organic acids and inorganic acidic substances such as nano silicon oxide, citric acid, gluconic acid, polycarboxylic acid, etc. Nano silicon oxide is preferred.

[0008] Alternatively, the molar amount of the neutralizing substance added is the same as the molar amount of the hydroxide generated by the hydration reaction.

[0009] The present invention also provides related concrete. The concrete is prepared using cement, fly ash, sand, aggregate, water reducing agent and liquid cementitious material prepared by the above method as raw materials. Furthermore, the raw materials for preparing the concrete also include mineral powder.

[0010] The present invention also provides a method for preparing the relevant concrete, and the provided preparation method comprises:

[0011] Step 1, using cement, fly ash, sand, aggregate and admixture as raw materials, designing a concrete formula to obtain an initial formula;

[0012] Step 2, based on the initial formula, the amount of fly ash is increased and the amount of cement is reduced, and the liquid cementitious material prepared by the above method is added at 2%-5% of the total mass of the material, and the solid content of the liquid cementitious material is 20%-30%;

[0013] Step 3: prepare concrete according to the formula designed in step 2.

[0014] An optional solution is that the increase in the mass of fly ash is the same as the reduction in the mass of cement.

[0015] Another method for preparing concrete provided by the present invention comprises:

[0016] Step 1, using cement, fly ash, sand, aggregate, mineral powder and admixture as raw materials, designing a concrete formula to obtain an initial formula;

[0017] Step 2, based on the initial formula, increase the amount of fly ash and mineral powder, reduce the amount of cement, and add 2%-5% of the total mass of the material prepared by the method of claim 1, and the solid content of the liquid cementitious material is 20%-30%;

[0018] Step 3: prepare concrete according to the formula designed in step 2.

[0019] An optional solution is that the increase in the total mass of fly ash and mineral powder is the same as the reduction in the mass of cement.

[0020] An optional solution is that the hydraulic cementitious material used in the preparation of the liquid cementitious material in step 2 of the above preparation method is the same as the cement used in step 1.

[0021] The present invention hydrates a hydraulic gelling material at room temperature and pressure, adds a substance to neutralize hydroxide in the system after hydration, then increases the reaction temperature and reaction pressure, performs a mechanochemical strengthening reaction, and forms a liquid gelling material after the reaction is completed. The liquid gelling material of the present invention is used for the production of various solid gelling materials, improves the early strength of the material (pre-strength before 28 days), and improves the volume stability of the material without affecting the later strength of the material (strength after 28 days) and the durability of the material. DETAILED DESCRIPTION

[0022] Unless otherwise defined, scientific and technical terms used herein are understood according to the understanding of ordinary technicians in the relevant fields.

[0023] The raw materials for preparing the concrete of the present invention are based on the existing raw materials for preparing concrete and the liquid cementitious material of the present invention is added thereto, and in the formula design, the components in the initial formula are adjusted based on the initial formula and then an appropriate amount of the liquid cementitious material of the present invention is added. The initial formula is a formula obtained by adopting the existing concrete formula design method. When preparing the concrete of the present invention, the order of adding each material follows the principle of the order of adding materials in the existing concrete, and in particular, the liquid cementitious material can be added simultaneously with water or successively with water.

[0024] The following are specific embodiments of the present invention. It should be noted that the specific reaction conditions involved in the following embodiments, such as concrete strength, material ratio, replacement amount of related substances in the formula, processing temperature, pressure, etc., are intended to explain the present invention. Based on the disclosure of this article, 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.

[0025] The reference sample formula design in the following examples refers to the existing "Ordinary Concrete Mix Design Code" JGJ55-2011. The concrete performance test in the following examples refers to "Ordinary Concrete Mechanical Performance Test Method" GB / T50081-2002; "Ordinary Concrete Mixture Performance Test Method" GB / T50080-2002.

[0026] Embodiment 1:

[0027] Preparation of the liquid cementitious material of this embodiment: 10 kg of PO 42.5 cement and 30 kg of water were mixed, and after hydration reaction for 10 hours, 2 kg of nano silicon oxide was added as a hydroxide neutralizer, and after mixing, the mixture was reacted under ultrasonic, 0.3 MPa and 60°C 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.

[0028] The C30 concrete was further prepared using the liquid cementitious material with a solid content of 25% in this embodiment; except for the liquid cementitious material, the remaining raw materials were: PO 42.5 cement, secondary fly ash, river sand, crushed gravel and polycarboxylate water reducer. This embodiment designed three groups of concrete samples:

[0029] The formula of the benchmark sample is: cement: fly ash: sand: stone: water: water reducing agent = 295:70:790:1020:175:11; the mixing method is: after adding the solid materials into the concrete mixer, slowly add water during the mixing process to mix evenly;

[0030] Trial 1: Based on the formula of the benchmark sample in this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the specific amount of liquid cementitious material is 3% of the total mass of all raw materials, and the fly ash replaces 30kg of cement in equal amounts; the mixing method is: after the solid materials are added to the concrete mixer, water and liquid cementitious material are slowly added during the mixing process to mix evenly;

[0031] Trial 2: Based on the formula of the benchmark sample in this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the specific amount of liquid cementitious material is 5% of the total mass of all raw materials, and the fly ash replaces 50 kg of cement in equal amounts; the mixing method is: solid materials are added to the mixer, and water and liquid cementitious material are slowly added during the mixing process;

[0032] The test results of each group of samples are shown in Table 1-2.

[0033] Table 1 Working performance test values

[0034]

[0035]

[0036] Table 2 Concrete strength test values

[0037]

[0038] Embodiment 2:

[0039] The difference between this embodiment and embodiment 1 is that the remaining raw materials of the concrete are: PO 42.5 cement, secondary mineral powder, secondary fly ash, river sand, crushed gravel, polycarboxylate water reducer; the three groups of samples are:

[0040] Benchmark sample formula: cement: mineral powder: fly ash: sand: stone: water: water reducing agent = 170: 100: 50: 1005: 840: 154: 15;

[0041] Trial 1: Based on the benchmark sample formula of this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the amount of liquid cementitious material added is 3% of the total mass of all raw materials, and 30kg of fly ash and 20kg of mineral powder replace 50kg of cement;

[0042] Trial preparation 2: Based on the benchmark sample formula of this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the amount of liquid cementitious material added is 5% of the total mass of all raw materials, and 30kg of fly ash and 20kg of mineral powder replace 50kg of cement.

[0043] The test results of each group of samples in this embodiment are shown in Table 3-4.

[0044] Table 3 Working performance test values

[0045]

[0046]

[0047] Table 4 Concrete strength test values

[0048]

[0049] Embodiment 3:

[0050] The difference between this embodiment and embodiment 1 is that the remaining raw materials of concrete are: PO 42.5 cement, third-grade fly ash, artificial machine-made sand, crushed gravel and polycarboxylate water reducer. The two groups of samples designed are:

[0051] Benchmark: cement: fly ash: sand: stone: water: water reducing agent = 260: 80: 821: 1090: 180: 12;

[0052] Trial 1: Based on the formula of the benchmark sample in this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the amount of liquid cementitious material prepared in Example 1 is 3% of the total mass of the raw materials used, and the fly ash replaces 40 kg of cement in equal amount;

[0053] The test results of each group of samples in this embodiment are shown in Tables 5-6.

[0054] Table 5 Working performance test values

[0055]

[0056] Table 6 Concrete strength test values

[0057]

[0058] Embodiment 4:

[0059] This embodiment is different from the embodiment 1 in that the remaining raw materials are: PO 42.5 cement, secondary fly ash, stone powder, river sand, crushed gravel and polycarboxylate water reducer, and the two groups of samples are:

[0060] Benchmark sample: cement: fly ash: stone powder: sand: stone: water: water reducing agent = 240: 100: 356: 563: 1000: 150: 8.5;

[0061] Trial preparation 1: Based on the benchmark sample formula of this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the specific amount of liquid cementitious material is 3% of the total mass of all raw materials, and the fly ash replaces 40 kg of cement in an equal amount.

[0062] The test results of each group of samples in this embodiment are shown in Tables 7-8.

[0063] Table 7 Working performance test values

[0064]

[0065] Table 8 Concrete strength test values

[0066]

[0067]

[0068] Embodiment 5:

[0069] This embodiment is different from the embodiment 1 in that the other raw materials used in this embodiment are: PO 42.5 cement, secondary fly ash, stone powder, river sand, crushed gravel and polycarboxylate water reducer; the three groups of samples set are:

[0070] Benchmark sample: cement: fly ash: stone powder: sand: stone: water: water reducing agent = 265: 40: 600: 390: 950: 135: 10.0;

[0071] Trial 1: On the basis of the benchmark sample formula of this embodiment, fly ash and liquid cementitious material (liquid cementitious material prepared in embodiment 1 after storage for 20 days) were added, and the amount of cement was reduced; the specific amount of liquid cementitious material was 3% of the total mass of all raw materials, and the fly ash replaced 30 kg of cement in equal amount;

[0072] Trial preparation 2: Based on the benchmark sample formula of this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the specific amount of liquid cementitious material is 5% of the total mass of all raw materials, and the fly ash replaces 40 kg of cement in an equal amount.

[0073] The test results of each sample in this embodiment are shown in Tables 9-10.

[0074] Table 9 Working performance test values

[0075]

[0076] Table 10 Concrete strength test values

[0077]

[0078]

[0079] Embodiment 6:

[0080] This embodiment is different from embodiment 1 in that the three groups of samples provided are:

[0081] Benchmark sample: cement: fly ash: sand: stone: water: admixture = 280: 95: 865: 980: 160: 9.4;

[0082] Trial 1: Based on the benchmark sample formula of this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the specific amount of liquid cementitious material is 3% of the total mass of all raw materials, and the fly ash replaces 36 kg of cement in equal amount;

[0083] Trial 2: Based on the formula of the benchmark sample in this embodiment, fly ash and liquid cementitious material are added to reduce the amount of cement; the specific amount of liquid cementitious material is 3% of the total mass of all raw materials, and the fly ash replaces 54kg of cement in equal amount;

[0084] The test results of each group of samples in this embodiment are shown in Tables 11-12.

[0085] Table 11 Working performance test values

[0086]

[0087] Table 12 Concrete strength test values

[0088]

[0089]

Claims

1. A method for preparing a liquid gelling material, characterized in that: The method comprises: mixing a hydraulic cementitious material having a strength greater than or equal to 32.5 MPa and water at a mass ratio of 1:(2-3) at room temperature and pressure, adding a neutralizing material after a hydration reaction for 9 to 12 hours and mixing evenly, then performing a chemical reaction at 50° C. to 90° C. and 0.1 to 1 MPa for 1 to 4 hours, and then cooling to room temperature to obtain a liquid cementitious material; The chemical reaction is carried out under the condition of ultrasound, stirring or vibration; The hydraulic cementitious material is selected from silicate cement, sulfate cement, sulphoaluminate cement or aluminate cement; The neutralizer is selected from nano silicon oxide or an acidic substance, the acidic substance is an organic acid and an inorganic acid, and the organic acid is citric acid, gluconic acid or polycarboxylic acid; The molar amount of the neutralizing substance added is the same as the molar amount of the hydroxide generated by the hydration reaction.

2. A concrete, characterized in that: The concrete is prepared using cement, fly ash, sand, aggregate, water reducing agent and the liquid cementitious material prepared by the method according to claim 1 as raw materials.

3. The concrete according to claim 2, characterized in that: The concrete preparation raw materials also include mineral powder.

4. A method for preparing concrete, characterized in that: Methods include: Step 1, using cement, fly ash, sand, aggregate and admixture as raw materials, designing a concrete formula to obtain an initial formula; Step 2, increasing the amount of fly ash and reducing the amount of cement on the basis of the initial formula, and adding 2%-5% of the total mass of the material prepared by the method of claim 1, and the solid content of the liquid cementitious material is 20%-30%; Step 3: prepare concrete according to the formula designed in step 2.

5. The method for preparing concrete according to claim 4, characterized in that: The increase in the mass of fly ash is the same as the reduction in the mass of cement.

6. The method for preparing concrete according to claim 4, characterized in that: Methods include: Step 1, using cement, fly ash, sand, aggregate, mineral powder and admixture as raw materials, designing a concrete formula to obtain an initial formula; Step 2, based on the initial formula, increase the amount of fly ash and mineral powder, reduce the amount of cement, and add 2%-5% of the total mass of the material prepared by the method of claim 1, and the solid content of the liquid cementitious material is 20%-30%; Step 3: prepare concrete according to the formula designed in step 2.

7. The method for preparing concrete according to claim 6, characterized in that: The increase in the total mass of fly ash and mineral powder is the same as the reduction in the mass of cement.

8. The method for preparing concrete according to claim 4 or 6, characterized in that: The hydraulic cementitious material used in the preparation of the liquid cementitious material in step 2 is the same as the cement used in step 1.

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