阅读说明：本技术 一种改性预拌厂废浆渣及其制备方法和在泡沫混凝土中的应用 (Modified waste slurry residue of ready-mix plant, preparation method thereof and application thereof in foam concrete ) 是由 黄暑年 王军 赵日煦 贺行洋 张恒春 黄汉洋 于 2019-11-11 设计创作，主要内容包括：本发明涉及一种改性预拌厂废浆渣及其制备方法和在泡沫混凝土中的应用。该改性预拌厂废浆渣,由预拌厂废浆渣、改性页岩陶砂、分散剂、纤维和水组成,其中改性页岩陶砂为页岩陶砂在茶皂素水溶液中浸润至吸水饱和。废浆渣经过改性处理后整体活性得到提升,浆体更匀质,可以作为外掺料掺入混凝土材料中,使得预拌厂压滤后的废浆渣利用效率显著增高。将改性预拌厂废浆渣用于泡沫混凝土中,可提高泡沫混凝土的浆体稳定性,改善抗裂、保温、强度等性能并解决了易开裂难养护等问题。本发明中改性预拌厂废浆渣制备方法简单,可以与整个泡沫混凝土生产过程衔接,实现改性与生产的同步进行,并形成一种预拌厂废浆渣高效利用的工艺流程和生产模式。(The invention relates to modified waste slurry slag of a ready-mixed plant, a preparation method thereof and application thereof in foam concrete. The modified waste slurry residue of the premixing plant consists of the waste slurry residue of the premixing plant, modified shale ceramic sand, a dispersant, fiber and water, wherein the modified shale ceramic sand is formed by soaking the shale ceramic sand in a tea saponin aqueous solution until the shale ceramic sand is saturated in water. The whole activity of the waste slurry slag is improved after modification treatment, the slurry is more uniform, and the waste slurry slag can be used as an external admixture to be doped into a concrete material, so that the utilization efficiency of the waste slurry slag after filter pressing in a premixing plant is obviously improved. The modified waste slurry residue of the premixing plant is used in the foam concrete, so that the slurry stability of the foam concrete can be improved, the performances of crack resistance, heat preservation, strength and the like are improved, and the problems of easy cracking, difficult maintenance and the like are solved. The preparation method of the modified waste slurry slag of the premixing plant is simple, can be linked with the whole foam concrete production process, realizes the synchronous modification and production, and forms a process flow and a production mode for efficiently utilizing the waste slurry slag of the premixing plant.)

1. The modified waste slurry residue of the ready-mix plant is characterized by consisting of the waste slurry residue of the ready-mix plant, modified shale ceramic sand, a dispersant, fiber and water, wherein:

the mass ratio of the waste slurry residue of the ready-mixed plant to the modified shale ceramic sand is 1 (0.6-0.9);

the mass ratio of the waste slurry residue of the pre-mixing plant, the dispersant and the fiber is as follows: 100: (1.1-1.5): (0.31-0.42);

the mass ratio of the waste slurry slag and the water in the ready-mix plant is as follows: 1: (1-1.5);

wherein the modified shale ceramic sand is prepared by soaking shale ceramic sand in tea saponin water solution until water absorption is saturated.

2. The modified ready-mix plant sludge as claimed in claim 1, wherein SiO is contained in the ready-mix plant sludge₂30.5-42.3 percent of CaO, 15.2-20.1 percent of Al₂O₃9.3-14.8% of Fe₂O₃3.5-6.5% of MgO and 1.9-2.6% of MgO.

3. The modified waste slurry residue of ready-mix plant as claimed in claim 1, wherein the shale ceramic sand has a bulk density of 780-830kg/m³The apparent density is 1530-1650kg/m³Saturated water absorption of 12.7-14.3%; the gradation composition is 10-30% of 1.18-2.36mm, 60-80% of 2.36-4.75mm and 5-10% of 4.75-9.5 mm.

4. The modified waste pulp residue of the ready-mix plant as claimed in claim 1, wherein the mass concentration of the aqueous solution of tea saponin is 0.3-0.5%.

5. The modified ready mixed mill waste pulp residue according to claim 1, wherein the dispersant is sodium polyacrylate; the fiber is polypropylene tow fiber with the length of 12-18mm, the tensile strength is more than or equal to 450MPa, and the fiber diameter is 12-21 mu m.

6. The preparation method of the modified waste slurry residue of the ready-mix plant as claimed in claim 1, which is characterized by comprising the following specific steps:

(1) mixing the waste slurry residue of the pre-mixing plant, water and fiber, and stirring in a stirrer for 10-20 minutes;

(2) adding the modified shale ceramic sand into the mixture obtained in the step (1), and continuously mechanically stirring for 30-40 minutes;

(3) adding a dispersing agent into the mixture obtained in the step (2), and continuously stirring until a uniform pasty mixture is obtained.

7. The foam concrete is characterized by comprising portland cement, modified ready-mixed plant waste slurry slag, a water reducing agent, a thickening agent, a composite foaming agent and water, wherein:

in each cubic of foam concrete, the mixing amount of the Portland cement is 300-500 kg;

the mass ratio of the Portland cement to the modified waste slurry residue of the pre-mixing plant is 1 (1.0-1.5);

the mass ratio of the Portland cement to the water reducing agent to the thickening agent to the composite foaming agent is as follows: 100: (0.30-0.42): (0.17-0.3): (0.17-0.42);

the mass ratio of the portland cement to the water is as follows: 1: (0.06-0.11).

8. The foamed concrete according to claim 7, wherein the portland cement is ordinary portland cement having a strength of not less than 42.5 MPa; the water reducing agent is a polycarboxylic acid water reducing agent, the solid content is 10.9-11.8%, and the water reducing rate is 25-29%.

9. The foamed concrete according to claim 7, wherein the thickener is a powdered mixture of low viscosity hydroxypropyl methylcellulose ether and polyvinyl alcohol in a mass ratio of 1: (1-4), wherein the viscosity of the hydroxypropyl methyl cellulose ether is 400-8000 mPa.s; the composite foaming agent is an animal and plant composite foaming agent, the foaming multiple of the diluted mother solution is 25-30 times, the settling distance is 3-5mm in 1h, and the bleeding rate is 32-40mL in 1 h.

10. A method of producing the foamed concrete of claim 7, comprising the steps of:

(1) adding cement, modified waste slurry residue of a premixing plant, a water reducing agent, a thickening agent and water into a stirrer and uniformly stirring;

(2) and (2) diluting the foaming agent with water, foaming, then fully mixing and stirring with the slurry aggregate obtained in the step (1), pouring and testing a mold, demolding, and then curing at normal temperature to obtain the foam concrete.

Technical Field

The invention belongs to the field of recycling of construction wastes, and particularly relates to modified waste slurry slag of a premixing plant, a preparation method thereof and application thereof in foam concrete.

Background

The waste slurry residue of the premixing plant is a mixture with uneven particles after passing through a sand-stone separator and a filter press, such as waste concrete in the premixing plant, waste slurry washed by a mixer truck, waste slurry washed by premixing equipment and the like, according to incomplete statistics, about 20kg of waste materials can be generated when 1 cubic meter of concrete is produced, about 16.4 billion cubic meters of concrete is produced every year in China, and the generation amount of the waste materials reaches 3280 million tons every year. Most of waste materials of the ready-mix plant are treated in a landfill mode in China, so that a large amount of land resources are occupied, and a heavy burden is caused to the environment. Therefore, the waste slurry of the premixing plant must be fully utilized to realize the recyclable utilization of resources and the green energy-saving production.

Relevant researches show that the waste slurry material of the pre-mixing plant has certain activity and can replace part of cement, but the waste slurry material is generally mixed into common concrete after being treated by processes of drying, grinding and the like, so that the energy consumption of the waste slurry material is relatively high, and the waste slurry material of the pre-mixing plant has certain limitation on the utilization of the waste material of the pre-mixing plant. Some researchers directly utilize the filtered waste slurry and slag, but the utilization rate of the waste slurry and slag is low.

The foam concrete is used as a porous, light, heat-insulating and energy-saving material and is widely applied to roof heat insulation, wall cast-in-place, road backfill and other projects. The production of the foam concrete has less dependence on the aggregate, if a large amount of waste materials in a premixing plant can be completely used for the production of the foam concrete, the premixing and the mass production of the foam concrete can be realized, the obvious effects on reducing the use of the aggregate and expanding the consumption of the waste materials are achieved, and finally, good environmental, social and economic benefits are realized. However, in practical application, particularly in the forming and hardening process, the foam concrete is difficult to maintain and is easy to shrink and crack.

Based on the current situation that the activity of the waste slurry slag of the ready-mix plant is not high, a simple and effective method for modifying the waste slurry slag of the ready-mix plant is urgently needed to improve the activity of the waste slurry slag so as to improve the performance of concrete when the waste slurry slag is used for foam concrete.

Disclosure of Invention

The invention aims to provide modified waste slurry slag of a premixing plant, a preparation method thereof and application thereof in foam concrete.

In order to solve the technical problems, the invention adopts the following technical scheme:

the modified waste slurry residue of the premixing plant consists of waste slurry residue of the premixing plant, modified shale ceramic sand, a dispersant, fibers and water, wherein:

the mass ratio of the waste slurry residue of the ready-mixed plant to the modified shale ceramic sand is 1 (0.6-0.9);

the mass ratio of the waste slurry residue of the pre-mixing plant, the dispersant and the fiber is as follows: 100: (1.1-1.5): (0.31-0.42);

the mass ratio of the waste slurry slag and the water in the ready-mix plant is as follows: 1: (1-1.5);

wherein the modified shale ceramic sand is prepared by soaking shale ceramic sand in tea saponin water solution until water absorption is saturated.

According to the scheme, SiO in the waste slurry slag of the pre-mixing plant₂30.5-42.3 percent of CaO, 15.2-20.1 percent of Al₂O₃9.3-14.8% of Fe₂O₃3.5-6.5% of MgO and 1.9-2.6% of MgO.

According to the scheme, the bulk density of the shale ceramic sand is 780-one 830kg/m³The apparent density is 1530-1650kg/m³Saturated water absorption of 12.7-14.3%; gradation of 1.18-2.36mm 10-30％，2.36-4.75mm 60-80％，4.75-9.5mm 5％-10％。

According to the scheme, the dispersing agent is sodium polyacrylate and is dissolved in water to provide a weak alkaline environment.

According to the scheme, the fiber is polypropylene tow fiber with the length of 12-18mm, the tensile strength is more than or equal to 450MPa, and the fiber diameter is 12-21 mu m.

According to the scheme, the mass concentration of the tea saponin aqueous solution is 0.3-0.5%.

A preparation method of the modified waste slurry residue of the ready-mix plant comprises the following specific steps:

(1) mixing the waste slurry residue of the pre-mixing plant, water and fiber, and stirring in a stirrer for 10-20 minutes;

(4) adding the modified shale ceramic sand into the mixture obtained in the step (1), and continuously mechanically stirring for 30-40 minutes;

(5) adding a dispersing agent into the mixture obtained in the step (2), and continuously stirring until a uniform pasty mixture is obtained.

The foam concrete is composed of portland cement, modified ready-mixed plant waste slurry slag, a water reducing agent, a thickening agent, a composite foaming agent and water, wherein:

in each cubic of foam concrete, the mixing amount of the Portland cement is 300-500 kg;

the mass ratio of the Portland cement to the modified waste slurry residue of the pre-mixing plant is 1 (1.0-1.5);

the mass ratio of the Portland cement to the water reducing agent to the thickening agent to the composite foaming agent is as follows: 100: (0.30-0.42): (0.17-0.3): (0.17-0.42)

The mass ratio of the portland cement to the water is as follows: 1: (0.06-0.11)

According to the scheme, the Portland cement is ordinary Portland cement with the strength of more than or equal to 42.5 MPa.

According to the scheme, the water reducing agent is a polycarboxylic acid water reducing agent, the solid content is 10.9-11.8%, and the water reducing rate is 25-29%.

According to the scheme, the thickening agent is a powdery mixture of hydroxypropyl methyl cellulose ether and polyvinyl alcohol with low viscosity, and the mass ratio of the hydroxypropyl methyl cellulose ether to the polyvinyl alcohol is 1: (1-4), wherein the viscosity of the hydroxypropyl methyl cellulose ether is 400-8000 mPa.s.

According to the scheme, the composite foaming agent is an animal and plant composite foaming agent, the foaming times of the diluted mother liquor are 25-30 times, the 1-hour settlement distance is 3-5mm, and the 1-hour bleeding rate is 32-40 mL.

The preparation method of the foam concrete comprises the following steps:

(1) adding cement, modified waste slurry residue of a premixing plant, a water reducing agent, a thickening agent and water into a stirrer and uniformly stirring;

(2) and (2) diluting the foaming agent with water, foaming, then fully mixing and stirring with the slurry aggregate obtained in the step (1), pouring and testing a mold, demolding, and then curing at normal temperature to obtain the foam concrete.

According to the scheme, the test mold is poured in the step (2), demolding is carried out after the normal-temperature curing is carried out for 24 hours, and then the normal-temperature curing is carried out for 28-42 days.

The waste slurry slag of the premixing plant has low overall activity due to uneven particles and different hydration degrees, the efficiency of homogenizing and refining the waste slurry slag is accelerated by the mechanical action of shale ceramic sand, fibers, a dispersing agent and the waste slurry slag, the average particle size of the waste slurry slag is reduced by carrying out physical and chemical modification on the waste slurry slag of the premixing plant, the surface energy of the particles is improved, the slurry is more uniform, the activity is further improved, the capillary pore stress between a hardened matrix and the matrix and between the matrix and the ceramic sand is reduced by spherical ceramic sand pretreated by a tea saponin solution, the later dehydration plays a role in maintenance, the apparent density of the ceramic sand is smaller, and the volume weight of the modified waste slurry of the premixing plant is reduced.

The modified waste slurry slag of the ready-mixed plant is applied to the foam concrete, and the performances of heat preservation, heat insulation, crack resistance and the like of the foam concrete can be improved. On one hand, the fibers can enhance the bonding force among foam concrete matrixes, improve the anti-cracking performance, have smaller apparent density of ceramic sand, can reduce the density of the foam concrete, reduce the quantity of foam introduced into the foam concrete, increase the slurry stability of the foam concrete, reduce the defects of internal pore structures and increase the later strength of the foam concrete; on the other hand, the modified shale ceramic sand loses water in the later period, so that the hydration of a matrix at an interface is promoted, the stress of a capillary channel is reduced, the cracking risk is reduced, the communication porosity of an internal structure is reduced, and the performances such as heat preservation, heat insulation and strength are improved to a certain extent.

The invention has the beneficial effects that:

1. the modified waste slurry and slag of the premixing plant provided by the invention has the advantages that the overall activity is improved, the slurry is more uniform, and the modified waste slurry and slag can be used as an external admixture to be doped into a concrete material, so that the utilization efficiency of the waste slurry and slag after filter pressing in the premixing plant is obviously improved, and the effects of self production, self marketing and zero emission are achieved.

2. The modified waste slurry slag of the ready-mix plant provided by the invention is mixed into the foam concrete, so that the slurry stability of the foam concrete is improved, the performances of crack resistance, heat preservation, strength and the like are improved, and the problems of easiness in cracking, difficulty in maintenance and the like are solved.

3. The preparation method of the modified waste slurry slag of the premixing plant provided by the invention is simple to operate, can be linked with the whole foam concrete production process, realizes the synchronous modification and production, and forms a process flow and a production mode for efficiently utilizing the waste slurry slag of the premixing plant.

Detailed Description

The present invention is further described below with reference to specific examples to facilitate the understanding of those skilled in the art.