CN112062521A - Large-volume concrete and preparation method thereof - Google Patents

Abstract

The invention provides a mass concrete and a preparation method thereof, which are characterized by comprising the following components in parts by weight: 170KG/M3 water, 308KG/M3 cement, 70KG/M3 mineral powder, 56KG/M3 fly ash, 10.3KG/M3 admixture, sand 694 KG/M3 and stone 1076 KG/M3. The performance of the mass concrete produced according to the invention can meet the requirements of strength grade, impermeability, stable volume and the like, and the hydration and temperature rise of the cementing material are controlled to achieve the purposes of reducing temperature pressure and preventing temperature cracks.

Description

Large-volume concrete and preparation method thereof

Technical Field

The invention relates to the field of buildings, in particular to mass concrete and a preparation method thereof.

Background

In the 'large-volume concrete construction standard' GB50496-2018 of China, the concrete with the minimum physical geometric dimension of a concrete structure not less than 1m is provided, or the concrete with harmful cracks caused by temperature change and shrinkage due to hydration of a cementing material in the concrete is expected, and the concrete is called large-volume concrete.

Modern buildings often involve large volume concrete construction, which is mainly characterized by a large volume, with a minimum dimension of 0.8m in either direction of the smallest cross-section. Its surface coefficient is smaller, the cement hydration heat release is more concentrated, and its internal temp. rise is faster. When the temperature difference between the inside and the outside of the concrete is large, the concrete can generate temperature cracks, and the structural safety and normal use are influenced. The existing mass concrete uses concrete waste, so that energy is saved, and environmental pollution is reduced; the waterproof performance of the concrete is improved by adding asphalt and a high-molecular reaction monomer through reaction; by using the auxiliary agent, the compression strength and the breaking strength of the concrete are increased, the fragrance of the concrete is increased, the antirust performance and the waterproof and anti-seepage performance are good, and the concrete has good water reducing performance, workability, plasticity and pumpability effect. But after the concrete waste material is corroded for a long time, the interior of the concrete waste material becomes soft and porous, so that after the concrete waste material is broken, a large number of micro cracks exist on the surface of the obtained particles, and after the concrete is subjected to the effects of load, temperature difference and the like, the micro cracks can be continuously expanded and communicated, so that the overall structural strength of the concrete is greatly reduced

Disclosure of Invention

According to the technical problems, the invention provides a mass concrete and a preparation method thereof, and the mass concrete is characterized by comprising the following components in parts by weight: 170KG/M3 water, 308KG/M3 cement, 70KG/M3 mineral powder, 56KG/M3 fly ash, 10.3KG/M3 admixture, sand 694 KG/M3 and stone 1076 KG/M3.

The cement is medium and low heat portland cement or heat slag portland cement.

The hydration heat of 3 days and 7 days of the cement meets the regulation of GB200 of moderate heat portland cement, low heat portland cement and low heat slag portland cement, when portland cement and ordinary portland cement are adopted, mineral mixed materials should be used, the hydration heat of a gel material in three days and seven days should not be larger than 240KJ/kg and 270KJ/kg respectively, and the hydration heat experimental method should be executed according to GB/T12959 of cement hydration heat determination method.

The sand is medium sand, the mud content is not more than 3%, and the fineness is constantly 2.6-2.8 mm.

The fly ash coarse aggregate is continuously matched, the maximum grain diameter is not suitable to be less than 31.5mm, and the mud content is not more than 1%.

The admixture comprises a retarding water reducer.

The additive comprises water gel, the water-gel ratio is not more than 0.55, and the water consumption is not more than 175 kg/M3.

The sand is coarse sand, and the sand rate is 38-42%.

On the premise of ensuring the performance requirement of concrete, the dosage of cement in the cementing material is reduced, and the doping amount of the mineral admixture is increased. The mixing amount of the mineral admixture in the concrete is 35 percent of the maximum mixing amount of the fly ash. When the ordinary portland cement is adopted, the water-cement ratio is less than or equal to 0.4, the maximum mixing amount of the granulated blast furnace slag powder is 55 percent, and when the ordinary portland cement is adopted, the water-cement ratio is less than or equal to 0.4.

A preparation method of mass concrete comprises the following steps:

step one, stirring and mixing water, cement, mineral powder, fly ash, sand and stones in corresponding parts by weight, and drying to obtain a mixture;

adding filling reinforcing materials and nano fillers in corresponding parts by weight into the mixture, and stirring and drying to obtain a base material;

step three, putting water, water glass and a water reducing agent in corresponding parts by weight into a stirring cylinder for stirring to obtain a mixed solution;

and step four, soaking the recycled concrete aggregate in the mixed solution, standing for a period of time, pouring the base material into the mixed solution for multiple times, and continuously stirring to obtain the high-strength concrete.

The invention has the beneficial effects that: the performance of the mass concrete produced according to the invention can meet the requirements of strength grade, impermeability, stable volume and the like, and the hydration and temperature rise of the cementing material are controlled to achieve the purposes of reducing temperature pressure and preventing temperature cracks.

The concrete with the large volume provided by the invention fully utilizes the later strength of the concrete, can adopt the strength of 60 days or 90 days as the mix proportion design and acceptance criterion of the concrete, and controls the adiabatic temperature rise of the concrete to be not more than 50 ℃ during mix proportion trial preparation and adjustment.

The invention adds the energy mineral powder which can effectively improve the compressive strength of the high-strength concrete, reduce the cost of the high-strength concrete, inhibit the reaction of the alkali aggregate, reduce the hydration heat, reduce the early temperature cracks of the high-strength concrete structure, improve the compactness of the high-strength concrete and have obvious effect on improving the anti-seepage and anti-erosion capabilities. The water reducing agent is a concrete admixture capable of reducing the mixing water consumption under the condition of maintaining the slump constant of the retarded concrete basically. The filling reinforcing material not only has good structural strength, but also has good dispersibility in high-strength concrete, and has good compatibility with raw materials of each component, thereby greatly improving the overall performance of the high-strength concrete.

Detailed Description

Example 1

The invention relates to a mass concrete and a preparation method thereof, which is characterized by comprising the following components in parts by weight: 170KG/M3 water, 308KG/M3 cement, 70KG/M3 mineral powder, 56KG/M3 fly ash, 10.3KG/M3 admixture, sand 694 KG/M3 and stone 1076 KG/M3.

The cement is medium and low heat portland cement or heat slag portland cement. The hydration heat of 3 days and 7 days of the cement meets the regulation of GB200 of moderate heat portland cement, low heat portland cement and low heat slag portland cement, when portland cement and ordinary portland cement are adopted, mineral mixed materials should be used, the hydration heat of a gel material in three days and seven days should not be larger than 240KJ/kg and 270KJ/kg respectively, and the hydration heat experimental method should be executed according to GB/T12959 of cement hydration heat determination method.

The sand is medium sand, the mud content is not more than 3%, and the fineness is constantly 2.6-2.8 mm. The fly ash coarse aggregate is continuously matched, the maximum grain diameter is not suitable to be less than 31.5mm, and the mud content is not more than 1%. The admixture comprises a retarding water reducer. The additive comprises water gel, the water-gel ratio is not more than 0.55, and the water consumption is not more than 175 kg/M3. The sand is coarse sand, and the sand rate is 38-42%. On the premise of ensuring the performance requirement of concrete, the dosage of cement in the cementing material is reduced, and the doping amount of the mineral admixture is increased. The mixing amount of the mineral admixture in the concrete is 35 percent of the maximum mixing amount of the fly ash. When the ordinary portland cement is adopted, the water-cement ratio is less than or equal to 0.4, the maximum mixing amount of the granulated blast furnace slag powder is 55 percent, and when the ordinary portland cement is adopted, the water-cement ratio is less than or equal to 0.4.

Example 2

A preparation method of mass concrete comprises the following steps:

step one, stirring and mixing water, cement, mineral powder, fly ash, sand and stones in corresponding parts by weight, and drying to obtain a mixture;

adding filling reinforcing materials and nano fillers in corresponding parts by weight into the mixture, and stirring and drying to obtain a base material;

step three, putting water, water glass and a water reducing agent in corresponding parts by weight into a stirring cylinder for stirring to obtain a mixed solution;

and step four, soaking the recycled concrete aggregate in the mixed solution, standing for a period of time, pouring the base material into the mixed solution for multiple times, and continuously stirring to obtain the high-strength concrete.

By adopting the technical scheme, the stones, the middlings, the fly ash, the Portland cement and the mineral powder are dried and stirred, so that the stones, the middlings, the fly ash, the Portland cement and the mineral powder are uniformly mixed, the high-strength concrete is prevented from being greatly reduced in quality due to the fact that parts of the stones, the middlings, the fly ash, the Portland cement and the mineral powder are bonded together, the filling reinforcing material and the nano filler are added and mixed, and the filling reinforcing material and the nano filler are fully. And soaking the recycled concrete aggregate in the mixed liquor for a period of time, so that the water glass is filled in the internal pores of the recycled concrete aggregate and fully plays a role. Meanwhile, the process for preparing the high-strength concrete is simple to operate, and the components can be quickly and uniformly mixed, so that the high-strength concrete has high production efficiency, and the overall quality can be guaranteed.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. While the invention has been described with respect to the above embodiments, it will be understood by those skilled in the art that the invention is not limited to the above embodiments, which are described in the specification and illustrated only to illustrate the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (10)

1. The mass concrete and the preparation method thereof are characterized by comprising the following components in parts by weight: 170KG/M3 water, 308KG/M3 cement, 70KG/M3 mineral powder, 56KG/M3 fly ash, 10.3KG/M3 admixture, sand 694 KG/M3 and stone 1076 KG/M3.

2. A mass concrete and method of making the same in accordance with claim 1 wherein said cement is medium and low heat portland cement or hot slag portland cement.

3. A mass concrete and its preparation method according to claim 1, characterized in that, the 3 days and 7 days hydration heat of the cement meet the regulation of "moderate heat portland cement, low heat slag portland cement" GB200, when portland cement and ordinary portland cement are used, mineral admixture should be participated, the three days and seven days hydration heat of the gel material should not be more than 240KJ/kg and 270KJ/kg respectively, and the hydration heat test method should be executed according to "cement hydration heat determination method GB/T12959".

4. The mass concrete and the method for preparing the same as claimed in claim 1, wherein the sand is medium sand, the content of the mud is not more than 3%, and the fineness is constantly 2.6-2.8 mm.

5. A mass concrete and its preparation method according to claim 1, characterized in that, the said fly ash coarse aggregate, for continuous match, should not be less than 31.5mm in maximum particle size, should not be greater than 1% mud content.

6. The mass concrete and the method for preparing the same as claimed in claim 1, wherein the admixture comprises a set-retarding water reducer.

7. A mass concrete and method of making the same as claimed in claim 1 wherein said admixture comprises a water gel, the water to gel ratio is not more than 0.55 and the amount of water used is not more than 175 kg/M3.

8. A mass concrete and method of making the same according to claim 1 wherein said sand is coarse sand with a sand rate of 38% to 42%.

9. The mass concrete and the method for preparing the same as claimed in claim 1, wherein the amount of cement used in the cementitious material is reduced and the amount of mineral admixture is increased while the performance requirements of the concrete are maintained. The mixing amount of the mineral admixture in the concrete is 35 percent of the maximum mixing amount of the fly ash. When the ordinary portland cement is adopted, the water-cement ratio is less than or equal to 0.4, the maximum mixing amount of the granulated blast furnace slag powder is 55 percent, and when the ordinary portland cement is adopted, the water-cement ratio is less than or equal to 0.4.

10. A mass concrete and method of making the same according to claim 1, wherein a mass concrete making method comprises the steps of:

step one, stirring and mixing water, cement, mineral powder, fly ash, sand and stones in corresponding parts by weight, and drying to obtain a mixture;

adding filling reinforcing materials and nano fillers in corresponding parts by weight into the mixture, and stirring and drying to obtain a base material;

step three, putting water, water glass and a water reducing agent in corresponding parts by weight into a stirring cylinder for stirring to obtain a mixed solution;

and step four, soaking the recycled concrete aggregate in the mixed solution, standing for a period of time, pouring the base material into the mixed solution for multiple times, and continuously stirring to obtain the high-strength concrete.