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Method for strengthening recycled concrete coarse aggregate by using CO2

A technology of recycled concrete and recycled coarse aggregate, applied in the direction of climate sustainability, sustainable waste treatment, solid waste management, etc., can solve the problems of poor economy, poor strengthening effect, complicated equipment, etc., and achieve low cost and carbonization The equipment and operation steps are simple and effective, and the effect is remarkable

Inactive Publication Date: 2018-11-02
ZHENGZHOU UNIVERSITY OF AERONAUTICS
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  • Abstract
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Problems solved by technology

However, this method has the disadvantage of poor economic efficiency; 4) pozzolanic material soaking method, which is based on the pozzolanic effect of pozzolanic materials and the micro-aggregate filling effect, thereby improving the quality of recycled aggregates
However, the mountain ash reaction in this method is limited by the calcium ion concentration in the pore solution, the alkalinity of the solution, and the reactivity of the pozzolanic material.
In addition, there are currently patented technologies that use carbon dioxide to strengthen recycled aggregates, but these disclosed patented technologies have disadvantages such as complex equipment and poor strengthening effects
It can be seen that the current reinforcement technology for recycled concrete aggregates has certain limitations and defects.

Method used

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  • Method for strengthening recycled concrete coarse aggregate by using CO2
  • Method for strengthening recycled concrete coarse aggregate by using CO2
  • Method for strengthening recycled concrete coarse aggregate by using CO2

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] This embodiment includes the following steps:

[0035] (1) Preparation of recycled concrete aggregate: the waste concrete is firstly crushed manually, then secondary crushed by a jaw crusher, and sieved to obtain recycled coarse aggregate with a particle size of 4.75 mm to 25 mm for later use;

[0036] (2) Pretreatment of recycled coarse aggregate: the prepared concentration of 0.1% nano-SiO 2 Drenching the slurry on the recycled coarse aggregate prepared in step (1), laying it flat and drying it for subsequent use;

[0037] (3)CO 2 Strengthen the recycled concrete aggregate: put the recycled coarse aggregate prepared in step (2) into the self-made carbonization device, and control the CO by controlling the air pressure regulating valve. 2 The carbonization pressure of the gas is 75KPa, and the carbonization duration is 30 minutes, and the recycled concrete aggregate is strengthened to obtain high-quality recycled concrete aggregate;

[0038] (4) Preparation of recyc...

Embodiment 2

[0040] This embodiment includes the following steps:

[0041] (1) Preparation of recycled concrete aggregate: the waste concrete is firstly crushed manually, then secondary crushed by a jaw crusher, and sieved to obtain recycled coarse aggregate with a particle size of 4.75 mm to 25 mm for later use;

[0042] (2) Regenerated coarse aggregate pretreatment: the prepared concentration is 0.2% nano-SiO 2Drenching the slurry on the recycled coarse aggregate prepared in step (1), laying it flat and drying it for subsequent use;

[0043] (3)CO 2 Strengthen the recycled concrete aggregate: put the recycled coarse aggregate prepared in step (2) into the self-made carbonization device, and control the CO by controlling the air pressure regulating valve. 2 The carbonization pressure of the gas is 75KPa, and the carbonization duration is 90min, and the recycled concrete aggregate is strengthened to obtain high-quality recycled concrete aggregate;

[0044] (4) Preparation of recycled co...

Embodiment 3

[0046] This embodiment includes the following steps:

[0047] (1) Preparation of recycled concrete aggregate: the waste concrete is firstly crushed manually, then secondary crushed by a jaw crusher, and sieved to obtain recycled coarse aggregate with a particle size of 4.75 mm to 25 mm for later use;

[0048] (2) Regenerated coarse aggregate pretreatment: the prepared concentration is 0.3% nano-SiO 2 Drenching the slurry on the recycled coarse aggregate prepared in step (1), laying it flat and drying it for subsequent use;

[0049] (3)CO 2 Strengthen the recycled concrete aggregate: put the recycled coarse aggregate prepared in step (2) into the self-made carbonization device, and control the CO by controlling the air pressure regulating valve. 2 The carbonization pressure of the gas is 150KPa, and the carbonization duration is 30 minutes, and the recycled concrete aggregate is strengthened to obtain high-quality recycled concrete aggregate;

[0050] (4) Preparation of recy...

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Abstract

The invention discloses a method for strengthening recycled concrete coarse aggregate by using CO2. The method comprises the following steps: (1) manually primary breaking waste concrete, secondary breaking the waste concrete by adopting a jaw-type breaking machine, screening to obtain recycled coarse aggregate for standby use; (2) sprinkling prepared nano SiO2 slurry onto the recycled coarse aggregate prepared in step (1), spreading, and air drying for standby use; (3) strengthening the recycled coarse aggregate prepared in step (2) in a self-made carbonization apparatus to obtain high-quality recycled concrete aggregate; and (4) completely substituting natural aggregate by using the recycled coarse aggregate strengthened by CO2 in step (3), and preparing recycled concrete. Compared withthe unprocessed recycled coarse aggregate, the water absorption rate of the recycled concrete coarse aggregate strengthened by CO2 is decreased by 18.98 to 34.17 percent, the breaking index is decreased by 13.79 to 31.03 percent, the void ratio is decreased by 3.85 to 13.47 percent, and the appearant density is increased by 1.13 to 4.55 percent.

Description

technical field [0001] The present invention relates to a method using CO 2 The invention discloses a method for strengthening recycled concrete coarse aggregate, which belongs to the technical field of construction waste regeneration application. Background technique [0002] Recycled concrete aggregate (referred to as recycled aggregate) refers to the aggregate obtained from waste concrete after crushing, grading, screening and other procedures, which can be partially or completely replaced by natural aggregate to prepare concrete. On the one hand, the application of recycled aggregate can solve the problem of land resources occupied by the arbitrary stacking of abandoned buildings; on the other hand, it can solve the problem of environmental damage caused by the unlimited exploitation and use of natural sand and gravel resources. Regenerated aggregate is composed of original aggregate and old mortar attached to the surface. Compared with natural aggregate, recycled aggre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B20/02C04B20/10C04B18/16
CPCC04B20/023C04B20/1066C04B18/16Y02W30/91
Inventor 武书华朱林张国红李雪张跃科徐国义张中华
Owner ZHENGZHOU UNIVERSITY OF AERONAUTICS
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