阅读说明：本技术 自密实混凝土及其制备方法 (Self-compacting concrete and preparation method thereof ) 是由 颜小淋 于 2020-06-24 设计创作，主要内容包括：本发明公开了一种自密实混凝土及其制备方法,包括：水泥112-154份,改性矿粉95～125份,煤灰75～85份,碎石800～1100份,粗砂195～233份,细砂455～580份,水110～150份及外加剂8～12份。本发明的混凝土流动性低水胶比、强度高、好操作,混凝土的密实性和抗压强度,且泵送压力小,泵送距离大。(The invention discloses a self-compacting concrete and a preparation method thereof, wherein the preparation method comprises the following steps: 154 parts of cement 112-doped materials, 95-125 parts of modified mineral powder, 75-85 parts of coal ash, 800-1100 parts of crushed stone, 195-233 parts of coarse sand, 455-580 parts of fine sand, 110-150 parts of water and 8-12 parts of additives. The concrete of the invention has low fluidity, high strength, good operation, compactness and compressive strength, small pumping pressure and large pumping distance.)

1. A self-compacting concrete, comprising: 154 parts of cement 112-doped materials, 95-125 parts of modified mineral powder, 75-85 parts of coal ash, 800-1100 parts of crushed stone, 195-233 parts of coarse sand, 455-580 parts of fine sand, 110-150 parts of water and 8-12 parts of additives.

2. A self-compacting concrete according to claim 1, characterized in that it comprises: 136 parts of cement, 107 parts of modified mineral powder, 77 parts of coal ash, 927 parts of broken stone, 204 parts of coarse sand, 469 parts of fine sand, 122 parts of water and 11.4 parts of an additive.

3. A semi-self-compacting concrete according to claim 1, comprising: 128 parts of cement, 114 parts of modified mineral powder, 81 parts of coal ash, 886 parts of crushed stone, 214 parts of coarse sand, 504 parts of fine sand, 116 parts of water and 8.9 parts of an additive.

4. A self-compacting concrete according to any one of claims 1-3, characterized in that: the additive is composed of the following raw materials in parts by weight: 3-6 parts of a polycarboxylic acid water reducing agent, 2-3 parts of a binder, 1-2 parts of an expanding agent, 2-3 parts of nano graphite and 1-2 parts of polystyrene nano microspheres.

5. A self-compacting concrete according to any one of claims 1-3, characterized in that: the additive is composed of the following raw materials in parts by weight: 4.6 parts of polycarboxylic acid water reducing agent, 2.3 parts of binder, 1.7 parts of expanding agent, 2.4 parts of nano graphite and 1.4 parts of polystyrene nano microspheres.

6. A self-compacting concrete according to any one of claims 1-3, characterized in that: the modified mineral powder is prepared by placing slag in a kiln, adding silicon carbide, silicon dioxide, limestone, activated carbon and polydimethylsiloxane, heating to 700-735 ℃, introducing nitrogen under 7-8.6 Mpa, keeping the temperature and pressure for 3-6 h, naturally cooling to normal temperature, and crushing into powder.

7. The self-compacting concrete of claim 6, wherein: the slag is one or a mixture of more of magnesite slag, steel slag, high-aluminum slag and glass slag.

8. A method for preparing a self-compacting concrete according to any one of claims 1-3, characterized in that it comprises the following steps:

step 1, uniformly stirring and mixing coal ash and 1/2 modified slag powder, adding coarse sand and broken stone, and mixing and stirring to form an aggregate mixture;

step 2, mixing and stirring the cement and the residual 1/2 modified slag powder uniformly to prepare a slurry mixture;

step 3, adding the slurry mixture prepared in the step 2 into the aggregate mixture prepared in the step 1, and uniformly stirring to prepare a mixture;

step 4, dissolving a polycarboxylic acid water reducing agent, a binder, an expanding agent, nano graphite and polystyrene nano microspheres in a copper nitrate solution, uniformly stirring, adding hydroxypropyl-BETA-cyclodextrin, heating to 40-46 ℃, and carrying out an oscillation reaction for 1.5 hours to prepare an additive;

and 5, adding the additive solution prepared in the step 4 into the mixture prepared in the step 3, and uniformly stirring to obtain the self-compacting concrete.

9. The method of claim 8, wherein the copper nitrate solution has a concentration of 0.975 g/L.

Technical Field

The invention relates to the technical field of concrete, in particular to self-compacting concrete and a preparation method thereof.

Background

At present, the requirements of limitation of thick and thin aggregates and low water-cement ratio are limited in the design of concrete mixing ratio, and a high-performance fluidized water reducing agent is matched to achieve the high compactness of concrete, so that the durability of the concrete and the protection of reinforcing steel bars are greatly improved and protected.

However, for general engineering, building construction and the like, the working performance of self-compacting concrete is not needed, and compared with common concrete used in general engineering, the self-compacting concrete has poor fluidity, low pumpability and low compactness and pressure resistance.

Disclosure of Invention

Based on the defects of the prior art, the invention provides self-compacting concrete.

In order to solve the above technical problems, the present invention provides a self-compacting concrete, comprising: 154 parts of cement 112-doped materials, 95-125 parts of modified mineral powder, 75-85 parts of coal ash, 800-1100 parts of crushed stone, 195-233 parts of coarse sand, 455-580 parts of fine sand, 110-150 parts of water and 8-12 parts of additives.

As an improvement of the technical scheme, the self-compacting concrete comprises: 136 parts of cement, 107 parts of modified mineral powder, 77 parts of coal ash, 927 parts of broken stone, 204 parts of coarse sand, 469 parts of fine sand, 122 parts of water and 11.4 parts of an additive.

As an improvement of the above technical solution, the method comprises the following steps: 128 parts of cement, 114 parts of modified mineral powder, 81 parts of coal ash, 886 parts of crushed stone, 214 parts of coarse sand, 504 parts of fine sand, 116 parts of water and 8.9 parts of an additive.

As an improvement of the technical scheme, the additive is composed of the following raw materials in parts by weight: 3-6 parts of a polycarboxylic acid water reducing agent, 2-3 parts of a binder, 1-2 parts of an expanding agent, 2-3 parts of nano graphite and 1-2 parts of polystyrene nano microspheres.

As an improvement of the technical scheme, the additive is composed of the following raw materials in parts by weight: 4.6 parts of polycarboxylic acid water reducing agent, 2.3 parts of binder, 1.7 parts of expanding agent, 2.4 parts of nano graphite and 1.4 parts of polystyrene nano microspheres.

As an improvement of the technical scheme, the modified mineral powder is prepared by placing slag in a kiln, adding silicon carbide, silicon dioxide, limestone, activated carbon and polydimethylsiloxane, heating to 700-735 ℃, introducing nitrogen under 7-8.6 Mpa, keeping the temperature and pressure for 3-6 h, naturally cooling to normal temperature, and crushing into powder.

As an improvement of the technical scheme, the slag is one or a mixture of more of magnesite slag, steel slag, high-alumina slag and glass slag.

Another object of the present invention is to provide a method for preparing self-compacting concrete, comprising the steps of:

step 1, uniformly stirring and mixing coal ash and 1/2 modified slag powder, adding coarse sand and broken stone, and mixing and stirring to form an aggregate mixture;

step 2, mixing and stirring the cement and the residual 1/2 modified slag powder uniformly to prepare a slurry mixture;

step 3, adding the slurry mixture prepared in the step 2 into the aggregate mixture prepared in the step 1, and uniformly stirring to prepare a mixture;

step 4, dissolving a polycarboxylic acid water reducing agent, a binder, an expanding agent, nano graphite and polystyrene nano microspheres in a copper nitrate solution, uniformly stirring, adding hydroxypropyl-BETA-cyclodextrin, heating to 40-46 ℃, and carrying out an oscillation reaction for 1.5 hours to prepare an additive;

and 5, adding the additive solution prepared in the step 4 into the mixture prepared in the step 3, and uniformly stirring to obtain the self-compacting concrete.

As an improvement of the technical scheme, the concentration of the copper nitrate solution is 0.975 g/L.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. the concrete of the invention has low fluidity, low water-cement ratio, high strength and good operation.

2. According to the invention, when the slag is modified, silicon carbide and activated carbon are used as precursors, and the slag is heated at high temperature to react with silicon dioxide and limestone, so that metal cations in the slag can be on a substrate using the limestone as a binder, and negative ions in the slag are adsorbed on the activated carbon, and the positive and negative ions in the raw materials are well dispersed, so that the modified slag powder has anisotropy, the fluidity of concrete is increased, and the compactness and compressive strength of the concrete are improved.

3. The concrete pump has small pumping pressure and large pumping distance.

Detailed Description

Other aspects, features and advantages of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.

Preparing modified mineral powder:

the modified mineral powder is prepared by placing slag in a kiln, adding silicon carbide, silicon dioxide, limestone, activated carbon and polydimethylsiloxane, heating to 700-735 ℃, introducing nitrogen under 7-8.6 Mpa, keeping the temperature and pressure for 3-6 h, naturally cooling to normal temperature, and crushing into powder. Wherein the slag, the silicon carbide, the silicon dioxide, the limestone, the active carbon and the polydimethylsiloxane are in parts by weight as follows: 12:3:4:2.6:2.5:1.8. The slag is one or a mixture of more of magnesite slag, steel slag, high-alumina slag and glass slag.

The modified mineral powder used in example 1-2 was prepared by placing a combination of magnesite slag, steel slag, high-alumina slag, and glass slag in a kiln (the modified mineral powder in example 3-4 was prepared by placing a combination of magnesite slag and high-alumina slag in a kiln), selecting a sealed type for the kiln, adding silicon carbide, silica, limestone, activated carbon, and polydimethylsiloxane, heating to 725 ℃, introducing nitrogen gas under 7.5Mpa, maintaining the temperature and pressure for 4.2 hours, naturally cooling to room temperature, and crushing to powder.

The modified mineral powder used in example 3-4 was prepared by placing a mixture of magnesite slag and steel slag in a kiln, adding silicon carbide, silicon dioxide, limestone, activated carbon and polydimethylsiloxane, heating to 730 ℃, introducing nitrogen at 8.5Mpa, maintaining the temperature and pressure for 3.6 hours, naturally cooling to room temperature, and crushing to powder.

The additive used in the invention is further composed of the following raw materials in parts by weight: 3-6 parts of a polycarboxylic acid water reducing agent, 2-3 parts of a binder, 1-2 parts of an expanding agent, 2-3 parts of nano graphite and 1-2 parts of polystyrene nano microspheres.

Furthermore, the additive is prepared from the following raw materials in parts by weight: 3-6 parts of a polycarboxylic acid water reducing agent, 2-3 parts of a binder, 1-2 parts of an expanding agent, 2-3 parts of nano graphite and 1-2 parts of polystyrene nano microspheres, dissolving the materials in a copper nitrate solution with the concentration of 0.975g/L, uniformly stirring, adding hydroxypropyl-BETA-cyclodextrin, heating to 40-46 ℃, and carrying out an oscillation reaction for 1.5 hours to prepare the polycarboxylic acid water reducing agent; hydroxypropyl-BETA-cyclodextrin and copper nitrate promote decomposition of polystyrene nanometer microsphere and reaction with hydroxypropyl-BETA-cyclodextrin, hydroxypropyl-polymer maintains chiral cavity structure of additive main body, and due to introduction of hydrophilic group hydroxypropyl, physicochemical properties of structure, water solubility, etc. of nanometer graphite and polystyrene nanometer microsphere, and performances of selectivity, fluidity, combination stability, etc. of foreign molecules are greatly improved.