阅读说明：本技术 一种用于路面砖的再生骨料混凝土材料及其制备方法 (Recycled aggregate concrete material for pavement bricks and preparation method thereof ) 是由 汪峻峰 徐平 游海棠 鲁刘磊 于 2021-01-11 设计创作，主要内容包括：本发明提供一种用于路面砖的再生骨料混凝土材料及其制备方法,该用于制备人行道的路面砖是以普通硅酸盐水泥、细骨料、粗骨料、水、硅灰、减水剂为主要原料制备而成；本发明有点在于将建筑垃圾中的废弃混凝土重新利用于路面砖的生产制造,同时利用加速碳化及活性粉末矿物掺合料对粗细再生骨料的性能进行改善。在节约资源,保护环境的同时,提高了建筑垃圾制备而成的路面砖的耐久性能及力学性能。成型后的再生骨料混凝土路面砖可以直接用于人行道铺设,无需额外装饰,视觉效果良好,质朴大方。(The invention provides a recycled aggregate concrete material for pavement bricks and a preparation method thereof, wherein the pavement bricks for preparing sidewalks are prepared by taking ordinary portland cement, fine aggregate, coarse aggregate, water, silica fume and a water reducing agent as main raw materials; the invention has the advantages that the waste concrete in the construction waste is reused for the production and the manufacture of the pavement bricks, and simultaneously, the performance of coarse and fine recycled aggregates is improved by utilizing accelerated carbonization and active powder mineral admixture. The method saves resources, protects the environment and improves the durability and mechanical property of the pavement brick prepared from the construction waste. The formed recycled aggregate concrete pavement brick can be directly used for paving sidewalks, does not need additional decoration, and is good in visual effect and simple and elegant in quality.)

1. A recycled aggregate concrete material for pavement bricks is characterized in that: the feed comprises the following raw materials in parts by weight: 0.3-1.2 parts of cement, 0.26-0.33 part of water, 2.5-4 parts of fine aggregate, 2.5-4 parts of coarse aggregate, 0.3-0.6 part of mineral admixture, 0.02-0.04 part of polycarboxylic acid water reducing agent, and the mineral admixture is silica fume.

2. A recycled aggregate concrete material for pavior bricks as claimed in claim 1, wherein: the feed comprises the following raw materials in parts by weight: 0.9 part of cement, 0.30 part of water, 3.2 parts of fine aggregate, 3.3 parts of coarse aggregate, 0.5 part of mineral admixture and 0.03 part of polycarboxylic acid water reducing agent.

3. A recycled aggregate concrete material for pavior bricks as claimed in claim 1, wherein: the aggregate is composed of recycled concrete aggregates with two particle sizes, namely fine aggregate with the particle size gradation of 1-4 mm and coarse aggregate with the particle size gradation of 4-9 mm.

4. A recycled aggregate concrete material for pavior bricks as claimed in claim 1, wherein: the blending ratio of the coarse aggregate to the fine aggregate is 1: 1.

5. A recycled aggregate concrete material for pavior bricks as claimed in claim 1, wherein: the polycarboxylate superplasticizer is a polycarboxylate superplasticizer with a polyester structure, wherein the main chain of the polycarboxylate superplasticizer is methacrylic acid, and the side chain of the polycarboxylate superplasticizer is carboxylic acid group.

6. A method for preparing a recycled aggregate concrete material for pavior bricks as claimed in claim 1, wherein: the method comprises the following steps:

s1, modification: stirring the mineral admixture and a polycarboxylic acid water reducing agent for 20-60 min, and drying at 40-60 ℃ for 60-200 min to obtain a modified mineral admixture;

s2, grinding: weighing fine aggregate, coarse aggregate and cement according to the weight parts, grinding, putting into water, soaking for 8-12 days, taking out, vacuum drying, adding a modified mineral admixture and water, and uniformly mixing to obtain mixed powder;

s3, carbonization: and carbonizing the mixed powder at 470-530 ℃ for 1.5-2.5 h to obtain the recycled aggregate concrete material.

7. A method for preparing recycled aggregate concrete material for pavior bricks as claimed in claim 6, characterized in that: the vacuum drying pressure in the step S2 is-0.09 MPa to-0.05 MPa.

Technical Field

The invention relates to the field of building materials, in particular to a recycled aggregate concrete material for a pavement brick and a preparation method thereof.

Background

The growing concern of civil engineering over-emission of greenhouse gases has led to a great interest in the development of new low-carbon cement-based materials. The recycled aggregate concrete is a hot research problem, and the construction waste is used as the coarse and fine aggregate of the concrete instead of the primary aggregate, so that the problems of land shortage and environmental pollution caused by landfill are solved, and the excessive exploitation of natural aggregates in the construction industry can be avoided. However, the recycled aggregate has the problem of a transition area of a new interface and an old interface, the strength of the mixed concrete is generally weakened, and the application of the recycled aggregate to a load bearing part in an engineering structure has more limitations. Therefore, the recycled aggregate concrete has great application potential for non-load-bearing parts, such as indoor floors, building partitions and the like. With the recent research on techniques for improving the properties of recycled aggregates, many recycled aggregate treatment techniques are widely used. Meanwhile, with the accelerated development of urban and rural integration in China, the demand on the pavement bricks is more than ever before. The prior pavement bricks are mostly made of sandstone cement as a raw material and are formed by processing. The coating is mainly paved on sidewalks, urban squares and other outdoor environments, is exposed in various complex environments for a long time, and has generally short service life and high maintenance cost. Therefore, the invention utilizes the advantages of the mineral admixture such as filling effect on the interface between the recycled aggregate and the slurry of the fresh water-mixing machine and improvement effect on the recycled aggregate by accelerated carbonization, applies the waste building rubbish to the production of the pavement stone through design and repeated trial and matching, saves resources, protects the environment, improves the durability and mechanical property of the prepared pavement brick, finally prolongs the service life of the pavement brick and improves the economic benefit.

Disclosure of Invention

In view of the above, the present invention provides a recycled aggregate concrete material for pavement bricks and a preparation method thereof, which solve the above problems.

The technical scheme of the invention is realized as follows: a recycled aggregate concrete material for pavement bricks comprises the following components: the feed comprises the following raw materials in parts by weight: 0.3-1.2 parts of cement, 0.26-0.33 part of water, 2.5-4 parts of fine aggregate, 2.5-4 parts of coarse aggregate, 0.3-0.6 part of mineral admixture, 0.02-0.04 part of polycarboxylic acid water reducing agent, and the mineral admixture is silica fume;

further, the recycled aggregate concrete material for the pavement bricks comprises the following raw materials in parts by weight: 0.9 part of cement, 0.30 part of water, 3.2 parts of fine aggregate, 3.3 parts of coarse aggregate, 0.5 part of mineral admixture and 0.03 part of polycarboxylic acid water reducing agent;

further, the aggregate is composed of recycled concrete aggregates with two particle sizes, namely fine aggregate with the particle size grading of 1-4 mm and coarse aggregate with the particle size grading of 4-9 mm;

furthermore, the blending ratio of the coarse and fine aggregates is 1: 1.

Further, the polycarboxylate superplasticizer is a polycarboxylate superplasticizer with a polyester structure, wherein the main chain of the polycarboxylate superplasticizer is methacrylic acid, and the side chain of the polycarboxylate superplasticizer is carboxylic acid group.

Further, the preparation method of the recycled aggregate concrete material for the pavement bricks comprises the following steps:

s1, modification: stirring the mineral admixture and a polycarboxylic acid water reducing agent for 20-60 min, and drying at 40-60 ℃ for 60-200 min to obtain a modified mineral admixture;

s2, grinding: weighing fine aggregate, coarse aggregate and cement according to the weight parts, grinding, putting into water, soaking for 8-12 days, taking out, vacuum drying, adding a modified mineral admixture and water, and uniformly mixing to obtain mixed powder;

s3, carbonization: and carbonizing the mixed powder at 470-530 ℃ for 1.5-2.5 h to obtain the recycled aggregate concrete material.

Further, the vacuum drying pressure in the step S2 is-0.09 MPa to-0.05 MPa.

Compared with the prior art, the invention has the beneficial effects that:

the method determines the optimal proportion of fine aggregate and coarse aggregate with different grain diameters by balancing the fluidity of slurry and the mechanical property of hardened concrete through fluidity determination; the two kinds of recycled aggregates with different grain diameters are subjected to accelerated carbonization treatment, so that the pore structure of the concrete and the bonding strength of surface mortar are improved; the adjustment mixing amount of the selected polycarboxylic acid water reducing agent can be adjusted to a certain degree according to the flowing property of the fresh slurry; the mineral mixing amount is adjusted, so that the mechanical property of the mineral is improved, and the mineral has good fluidity.

The invention has the advantages that the waste concrete in the construction waste is reused for the production and the manufacture of the pavement bricks, and simultaneously, the performance of coarse and fine recycled aggregates is improved by utilizing accelerated carbonization and active powder mineral admixture. The method saves resources, protects the environment and improves the durability and mechanical property of the pavement brick prepared from the construction waste. The formed recycled aggregate concrete pavement brick can be directly used for paving sidewalks, does not need additional decoration, and is good in visual effect and simple and elegant in quality.

Detailed Description

In order to better understand the technical content of the invention, specific examples are provided below to further illustrate the invention.

The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.

The materials, reagents and the like used in the examples of the present invention can be obtained commercially without specific description.

Example 1

A recycled aggregate concrete material for pavement bricks comprises the following components: the feed comprises the following raw materials in parts by weight: 0.3 part of cement, 0.26 part of water, 2.5 parts of fine aggregate, 2.5 parts of coarse aggregate, 0.3 part of mineral admixture and 0.02 part of polycarboxylic acid water reducing agent, wherein the mineral admixture is silica fume.

Example 2

A recycled aggregate concrete material for pavement bricks comprises the following components: the feed comprises the following raw materials in parts by weight: 1.2 parts of cement, 0.26-0.33 part of water, 2.5-4 parts of fine aggregate, 2.5-4 parts of coarse aggregate, 0.3-0.6 part of mineral admixture, 0.02-0.04 part of polycarboxylic acid water reducing agent, and the mineral admixture is silica fume.

Example 3

A recycled aggregate concrete material for pavement bricks comprises the following raw materials in parts by weight: 0.9 part of cement, 0.30 part of water, 3.2 parts of fine aggregate, 3.3 parts of coarse aggregate, 0.5 part of mineral admixture and 0.03 part of polycarboxylic acid water reducing agent;

the preparation method of the above examples 1 to 3 is as follows:

s1, modification: stirring the mineral admixture and a polycarboxylic acid water reducing agent for 40min, and drying at 50 ℃ for 60-200 min to obtain a modified mineral admixture;

s2, grinding: weighing fine aggregate, coarse aggregate and cement according to the weight parts, grinding, putting into water, soaking for 10 days, taking out, vacuum drying under the pressure of-0.07 MPa, adding a modified mineral admixture and water, and uniformly mixing to obtain mixed powder;

s3, carbonization: and (3) carbonizing the mixed powder at 500 ℃ for 2h to obtain the recycled aggregate concrete material.

Example 4

The difference between the embodiment and the embodiment 3 is that the preparation method of the recycled aggregate concrete material for the pavement bricks comprises the following steps:

s1, modification: stirring the mineral admixture and a polycarboxylic acid water reducing agent for 20min, and drying at 40 ℃ for 60min to obtain a modified mineral admixture;

s2, grinding: weighing fine aggregate, coarse aggregate and cement according to the weight parts, grinding, putting into water, soaking for 8 days, taking out, vacuum drying under the pressure of-0.09 MPa, adding a modified mineral admixture and water, and uniformly mixing to obtain mixed powder;

s3, carbonization: and (3) carbonizing the mixed powder at 470 ℃ for 1.5h to obtain the recycled aggregate concrete material.

Example 5

The difference between the embodiment and the embodiment 3 is that the preparation method of the recycled aggregate concrete material for the pavement bricks comprises the following steps:

s1, modification: stirring the mineral admixture and a polycarboxylic acid water reducing agent for 60min, and drying at 60 ℃ for 200min to obtain a modified mineral admixture;

s2, grinding: weighing fine aggregate, coarse aggregate and cement according to the weight parts, grinding, putting into water, soaking for 12 days, taking out, vacuum drying under the pressure of-0.05 MPa, adding a modified mineral admixture and water, and uniformly mixing to obtain mixed powder;

s3, carbonization: and (3) carbonizing the mixed powder at 530 ℃ for 2.5 hours to obtain the recycled aggregate concrete material.

Comparative example 1

The difference between the comparative example and the example 3 is that the recycled aggregate concrete material for the pavement brick comprises the following raw materials in parts by weight: 0.2 part of cement, 0.20 part of water, 2.0 parts of fine aggregate, 2.0 parts of coarse aggregate, 0.2 part of mineral admixture and 0.01 part of polycarboxylic acid water reducing agent.

Comparative example 2

The difference between the comparative example and the example 3 is that the recycled aggregate concrete material for the pavement brick comprises the following raw materials in parts by weight: 0.2 part of cement, 0.20 part of water, 2.0 parts of fine aggregate, 2.0 parts of coarse aggregate, 0.5 part of mineral admixture and 0.03 part of polycarboxylic acid water reducing agent.

Comparative example 3

The difference between the comparative example and the example 3 is that the recycled aggregate concrete material for the pavement brick comprises the following raw materials in parts by weight: 0.9 part of cement, 0.30 part of water, 3.2 parts of fine aggregate, 3.3 parts of coarse aggregate, 0.2 part of mineral admixture and 0.01 part of polycarboxylic acid water reducing agent.

First, performance detection

1. Compressive strength: the test is carried out by referring to the compression strength test method disclosed in GB/T4111-2013 'Experimental method for cutting and brick of coagulated milk', the compression strength of different products is calculated,

2. breaking strength: the test is carried out according to the flexural strength test method disclosed in GB/T4111-2013 'Experimental method for cutting and brick of coagulated milk', the compressive strength of different products is calculated, and the results are shown in the following table:

	compressive strength (MPa)	Flexural strength (MPa)
			Example 1	55.6	5.03
Example 2	55.3	5.26
			Example 3	58.6	5.36
Example 4	51.1	4.69
			Example 5	53.6	4.51
Comparative example 1	49.5	3.15
			Comparative example 2	48.3	3.56
Comparative example 3	48.4	3.26

From the above table, it can be seen that the concrete products prepared from the concrete materials prepared in examples 1 to 5 have high compressive strength and flexural strength, and the compressive strength and the flexural strength are effectively improved by combining the modification treatment process and the specific preparation method, and the concrete materials prepared in comparative examples 1 to 3 have slightly low compressive strength and flexural strength due to different raw material ratios.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.