Aggregate treatment method for enhancing chlorine salt erosion resistance of construction waste recycled concrete

A technology for recycling concrete and construction waste, applied in the direction of sustainable waste treatment, climate sustainability, solid waste management, etc. The effect is limited and other problems, to achieve the effect of being conducive to consumption and recycling, reducing the chloride ion migration coefficient, and significantly improving performance.

Inactive Publication Date: 2019-06-07
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the equipment investment required by the physical method is large, and the wear and power consumption are also large, which can promote the internal damage of the recycled coarse aggregate; the biological method is immature, and the test conditions are harsh and difficult to control; the chemical method The solution impregnation method mostly uses organosilane, organic polymer solution or some other waterproof materials, which are expensive; due to the low content of alkaline substances in the recycled aggregate, the traditional method of carbonizing the aggregate can improve the chlorine salt erosion resistance of recycled concrete The effect is not significant; the acid solution immersion method is highly corrosive, has certain damage to the carbonate aggregate, and destroys the alkaline environment inside the recycled concrete; the grouting method is to mix cement, fly ash, mineral powder, silica fume, etc. The slurry formed by single or multiple materials wraps the recycled aggregate. The process is simple and economical, but the improvement effect is limited

Method used

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  • Aggregate treatment method for enhancing chlorine salt erosion resistance of construction waste recycled concrete
  • Aggregate treatment method for enhancing chlorine salt erosion resistance of construction waste recycled concrete
  • Aggregate treatment method for enhancing chlorine salt erosion resistance of construction waste recycled concrete

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Effect test

Embodiment 1

[0028] This embodiment includes the following steps:

[0029] (1) Preparation of recycled coarse aggregate from construction waste: coarsely classify waste concrete construction waste, sort and remove impurities, crush and sieve, etc., to obtain recycled coarse aggregate with a particle size range of 5-25 mm, and air-dry naturally for backup use.

[0030] (2) Pretreatment of recycled coarse aggregate of construction waste: immerse the recycled coarse aggregate obtained in step (1) in slaked lime emulsion with a concentration of 1:10 for 30 minutes, and stir it every 10 minutes, then take it out and store it indoors. Let it dry for 24 hours, then move it into an oven at 60°C for drying.

[0031] (3) Neutralization treatment of recycled coarse aggregate of construction waste: spread the recycled coarse aggregate obtained in step (2) on a tray, and move it into a concrete carbonation box (control temperature is 20±3°C, gas concentration is 20 ±3%, and the humidity is 70±5°C) fo...

Embodiment 2

[0042] This embodiment includes the following steps:

[0043] (1) Preparation of recycled coarse aggregate from construction waste: coarsely classify waste concrete construction waste, sort and remove impurities, crush and sieve, etc., to obtain recycled coarse aggregate with a particle size range of 5-25 mm, and air-dry naturally for backup use.

[0044](2) Pretreatment of recycled coarse aggregate of construction waste: soak the recycled coarse aggregate obtained in step (1) in slaked lime emulsion with a concentration of 1:20 for 60 minutes, and stir it every 10 minutes, then take it out, and store it indoors. Let it dry for 24 hours, then move it into an oven at 80°C for drying.

[0045] (3) Neutralization treatment of recycled coarse aggregate of construction waste: spread the recycled coarse aggregate obtained in step (2) on a tray, and move it into a concrete carbonation box (control temperature is 20±3°C, gas concentration is 20 ±3%, and the humidity is 70±5°C) for n...

Embodiment 3

[0055] This embodiment includes the following steps:

[0056] (1) Preparation of recycled coarse aggregate from construction waste: coarsely classify waste concrete construction waste, sort and remove impurities, crush and sieve, etc., to obtain recycled coarse aggregate with a particle size range of 5-25 mm, and air-dry naturally for backup use.

[0057] (2) Pretreatment of recycled coarse aggregate of construction waste: immerse the recycled coarse aggregate obtained in step (1) in slaked lime emulsion with a concentration of 1:15 for 40 minutes, and stir it every 10 minutes, then take it out, and store it indoors. Let it dry for 24 hours, then move it into a 70°C oven for drying.

[0058] (3) Neutralization treatment of recycled coarse aggregate of construction waste: spread the recycled coarse aggregate obtained in step (2) on a tray, and move it into a concrete carbonation box (control temperature is 20±3°C, gas concentration is 20 ±3%, and the humidity is 70±5°C) for n...

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Abstract

The invention discloses an aggregate treatment method for enhancing chlorine salt erosion resistance of construction waste recycled concrete, which comprises the following steps: (1) carrying out processes of coarse separation, separation and impurity removal, crushing and screening and the like on waste concrete construction waste to obtain construction waste recycled coarse aggregate, and naturally air-drying the recycled coarse aggregate for later use; (2) impregnating the recycled coarse aggregate obtained in the step (1) into a slaked lime emulsion, stirring the liquid once every 10 minutes, taking out the recycled coarse aggregate, airing the recycled coarse aggregate indoors for 24 hours, and transferring the recycled coarse aggregate into a drying box for drying; (3) spreading therecycled coarse aggregate obtained in the step (2) on a tray, and moving the recycled coarse aggregate into a concrete carbonization box for neutralization treatment; (4) completely replacing the natural macadam aggregate with the recycled coarse aggregate obtained in the step (3) to prepare the recycled concrete. The treatment method has a remarkable improvement effect on the chlorine salt erosion resistance of the recycled concrete.

Description

technical field [0001] The invention relates to an aggregate treatment method for enhancing the anti-chlorine salt erosion performance of recycled concrete, and belongs to the technical field of recycling of waste concrete construction waste. Background technique [0002] At present, our country is in the peak period of infrastructure construction and needs to consume a lot of cement and concrete materials. If only natural stone is used to produce concrete, the over-exploitation of sand and gravel aggregates will inevitably cause serious damage to the ecological environment. At the same time, a large amount of construction waste is produced along with the construction of large-scale new concrete structures and the demolition of old structures. If they are not effectively treated, they will cause a series of problems, such as occupying valuable land, and causing environmental and social problems. At present, the main way to recycle construction waste is to produce recycled a...

Claims

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Application Information

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IPC IPC(8): C04B20/02C04B18/16
CPCY02W30/91
Inventor 张金喜王建刚党海笑丁博
Owner BEIJING UNIV OF TECH
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