Recycled aggregate freezing and thawing cycle pretreatment method

A recycled aggregate and freeze-thaw cycle technology, applied in the direction of sustainable waste treatment, solid waste management, climate sustainability, etc., can solve the problems of poor durability, limited application range, low strength, etc., and achieve high physical bonding strength , Reduce physical damage, high packing density

Inactive Publication Date: 2018-10-19
ANHUI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When traditional crushers crush aggregates, the aggregates will collide with each other to cause greater physical damage, resulting in small cracks inside the recycled aggregates. Therefore, recycled aggregates have their own shortcomings, such as large water absorption and high pulverized coal content. , high porosity, large crushing index, low density, etc. If it is directly applied to concrete, it will lead to poor workability of freshly mixed recycled concrete, low strength and poor durability after hardening, which greatly limits its application range

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Use a cone crusher to crush the waste concrete for the first time into coarse aggregate with a particle size of less than 100mm; use an electromagnetic separation device and a gravity separation device to remove impurities such as steel bars, wood chips, broken glass, and plastic in the waste concrete; The waste concrete with impurities removed is soaked in water for more than 4 hours to allow water to fully penetrate into the structure.

[0029] Put the soaked aggregate into the freeze-thaw cycle system for a certain number of freeze-thaw cycles, using the method of water freezing and water dissolution, the high temperature should be above (20±2)℃, and the low temperature (-20±2)℃ below, once Freeze-thaw is a cycle, and a cycle time is not less than 4h; it experiences 10 freeze-thaw cycles.

[0030] The second crushing is carried out in the cone crusher, and it is crushed into coarse aggregates with a particle size of 31.5mm or less; the aggregates that have undergone the s...

Embodiment 2

[0032] Use a cone crusher to crush the waste concrete for the first time to make coarse aggregate with a particle size of less than 100mm; use a conveyor belt to set up an artificial separation platform to remove impurities such as steel bars, wood chips, broken glass, and plastic in the waste concrete; The waste concrete with impurities is soaked in water for more than 4 hours to allow water to fully penetrate into the structure.

[0033] Put the soaked aggregate into the freeze-thaw cycle system for a certain number of freeze-thaw cycles, using air-freezing and water-dissolving methods, the high temperature should be above (20±2)℃, and the low temperature (-20±2)℃ below, once The freeze-thaw cycle is a cycle, and the cycle time is not less than 8h; after the freeze-thaw cycle reaches 10 times, it is crushed for the second time in a cone crusher, and crushed into coarse aggregate with a particle size of 31.5mm or less; The secondary crushed aggregate is poured into the drum ston...

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Abstract

The invention relates to a recycled aggregate freezing and thawing cycle pretreatment method which specially comprises the following steps: primarily breaking, removing impurities, soaking, performingfreezing and thawing cycle, secondarily breaking, performing cleaning and polishing, performing sieving and the like. Through the freezing and thawing cycle pretreatment, expansion pressure generatedwhen water is frozen on inner walls of concrete holes is utilized to make concrete generate cracks from the inner weak positions; after ice melts into water, the water can go deep into the interior of a structure through the cracks without taking extra trouble. Through certain times of freezing and thawing cycles, many fine and small cracks can be generated at the weak positions inside the structure of concrete which has low compressive strength and not compact internal structure; when being broken again, the concrete can be broken along the structural cracked positions to form the recycled coarse aggregate which has the advantages of high strength, small holes, large crushing index and low silt content.

Description

Technical field [0001] The invention relates to the technical field of production and application of recycled aggregates, in particular to a pretreatment method of recycled aggregate freeze-thaw cycles. Background technique [0002] With the development of economy and the acceleration of urban construction, more and more concrete around the world has been demolished or rebuilt because it has reached the service life and cannot meet the requirements. A large amount of construction waste has caused the depletion of natural resources in some areas, a large amount of soil and water loss, the destruction of rivers and the serious deterioration of natural landscapes, etc., resulting in increasingly severe forms of ecological environment resources. [0003] At present, in order to effectively utilize construction waste, it is generally prepared into recycled aggregate in the world to realize resource utilization. When the traditional crusher crushes the aggregate, the aggregates collide ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B18/16C04B20/02
CPCC04B18/16C04B20/026C04B20/02Y02W30/91
Inventor 吴素瑶徐敏卢珊
Owner ANHUI UNIV OF SCI & TECH
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