Cement concrete recycling method

A cement concrete, recycling technology, used in cement production, sustainable waste treatment, solid waste management, etc.

Inactive Publication Date: 2012-06-20
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method truly realizes the sustainable utilization of non-renewable resources in cement concrete, which has not been reported in domestic and foreign literature

Method used

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Experimental program
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Effect test

Embodiment 1

[0020] This method can already be implemented in the laboratory: the method is to use 100mm × 100mm × 100mm concrete, the coarse aggregate of the concrete is limestone crushed stone, the fine aggregate is limestone machine-made sand, and the test piece is directly placed in a 4kw microwave oven. After microwave irradiation, the temperature of the slurry part reaches about 750 °C, the surface temperature of the coarse aggregate is 482 °C, and the internal temperature is 96 °C. almost disappeared. The measured strength of the concrete test block is 0.46MPa, which can be easily peeled off. It only needs to be bumped several times on the aggregate screen and crushed with a little force to separate. The aggregate can become recycled aggregate after sorting. The composition of the dehydrated phase of the remaining cement slurry is similar to that of the Portland cement raw meal, except that the calcium oxide content is slightly higher. A small amount of clay and iron powder are add...

Embodiment 2

[0022] Take the waste concrete demolished from a construction site, use a metal detector to test that there is no rebar residue, and put it into a 4kw microwave oven. After microwave radiation, the temperature of the slurry part reaches about 850 °C, and the surface temperature of the tested coarse aggregate is 532 °C , the internal temperature is 187 ℃, there is basically no bonding strength between the slurry and the aggregate, and the gelatinity of the slurry is almost disappeared, which can be easily peeled off, just after several bumps and a little force on the aggregate screen Crush to separate. The aggregate can become recycled aggregate after sorting. The composition of the dehydrated phase of the remaining cement slurry is similar to that of Portland cement raw meal, except that the content of silica is slightly higher and the calcium oxide is slightly lower. A small amount of limestone and iron powder are added for correction, and silicon dioxide can be obtained by c...

Embodiment 3

[0024] Take the waste concrete demolished at a construction site, use a metal detector to test that there is no rebar residue, and put it into a 4kw microwave oven. After microwave radiation, the temperature of the slurry part can reach about 980 ℃, and the surface temperature of the tested coarse aggregate is 604 °C, the internal temperature is 246 °C, there is basically no bonding strength between the slurry and the aggregate, and the gelatinity of the slurry is almost disappeared, which can be easily peeled off. Crush hard to separate. The aggregate can become recycled aggregate after sorting. The composition of the dehydrated phase of the remaining cement slurry is similar to that of Portland cement raw meal, except that the content of silica and alumina is slightly higher, and the calcium oxide is slightly lower. Portland cement clinker can be obtained at 1400 ℃, and cement can be obtained by adding gypsum and grinding. These recovered aggregates and recycled cement can...

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Abstract

A cement concrete recycling method is disclosed, which comprises three parts of stripping aggregates and slurries in waste concrete, regenerating the aggregates and regenerating the slurries. A microwave heat treatment method is adopted for stripping the aggregates and slurries in the waste concrete, and mainly comprises the following steps: utilizing the difference between the microwave absorbing capability of the slurries and the microwave absorbing capability of the aggregates, putting the waste concrete into a sealed device provided with a microwave generator, subjecting the waste concrete to microwave irradiation so as to increase the temperature until the concrete is made brittle by irradiation, rotating the brittle concrete in a cylinder with a gridding lining, and utilizing the mutual collision to thoroughly strip the slurries and the aggregates. The aggregate regeneration comprises the following steps: for the aggregates stripped from the concrete, screening the residual part after a powder concentrator collects a part of the dehydrated phase powders of cement slurries, and preparing into regenerated aggregates of different sizes. The slurry regeneration comprises the following steps: according to different chemical compositions of the dehydrated phases of the cement slurries, blending and correcting raw materials specifically, enabling the rate of the raw material to meet the requirements of silicate cement raw material, and then adopting a traditional kiln or microwave to sinter and prepare silicate cement.

Description

technical field [0001] The invention relates to a cement concrete recycling method, which includes three parts: aggregate slurry stripping, aggregate regeneration and paste regeneration in waste concrete. The method is suitable for the recycling and regeneration of different grades of concrete. Background technique [0002] Cement concrete is currently the most widely used material due to its cheapness, high strength and ease of being made into required shapes. However, in recent years, due to the huge carbon emissions of cement (about 0.6 to 1 ton of carbon dioxide per ton of cement produced and used), resource consumption It has been criticized for its high energy consumption and difficult recycling. But as the cornerstone of the modern construction industry, cement concrete will be widely used as an irreplaceable building material for a long time to come. Therefore, how to realize the recycling of concrete is one of the huge technical challenges faced by cement concrete ...

Claims

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Application Information

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IPC IPC(8): C04B7/24C04B18/16
CPCY02P40/10Y02W30/91
Inventor 沈卫国水中和王桂明周明凯谭昱董瑞陈虎甘戈金
Owner WUHAN UNIV OF TECH
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