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Recycling and reusing method of cement concrete waste

A technology for cement concrete and waste, applied in the field of building materials, can solve the problems of difficult to meet the performance of recycled aggregate concrete products, high porosity and water absorption rate of recycled aggregate, and limit the wide application of recycled aggregates, etc. Industrial application, the effect of improving shrinkage performance and increasing strength

Active Publication Date: 2016-10-05
THE HONG KONG POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the complexity of recycled aggregate components and a large amount of old mortar attached to its surface, the porosity and water absorption of recycled aggregate are higher than those of natural aggregate, and the strength and elastic modulus are lower, making recycled aggregate concrete The performance of the product is difficult to meet the needs of actual engineering, especially the recycled fine aggregate of waste concrete, which limits the wide application of recycled aggregate to a large extent

Method used

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  • Recycling and reusing method of cement concrete waste
  • Recycling and reusing method of cement concrete waste
  • Recycling and reusing method of cement concrete waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] (1) Preparation of recycled building wall bricks

[0036] In 2014, the sedimentation tank mortar in the mixing plant was randomly recovered at different times. The mortar came from a cement concrete mixing plant in Hong Kong and was made into a slurry using a mixer. The XRF analysis of the chemical composition of the slurry is shown in Table 1.

[0037] Table 1 XRF analysis of chemical composition of recycled mortar in different periods in 2014

[0038]

[0039] According to Table 2, mix ordinary silicate No. 52.5 cement and recycled aggregate of cement concrete waste from Hong Kong's recycled construction waste crushing plant with a particle size of less than 5mm, and its apparent density is 2625kg / m 3 , The aggregate density is 2205kg / m 3 , The water absorption rate is 15.8%, and the impurity content is 3.5wt%.

[0040] Table 2 The proportion of materials used in the preparation of building wall bricks with mortar in the sedimentation tank of the concrete mixing station

[0041...

Embodiment 2

[0051] (1) Preparation of recycled concrete pavement bricks

[0052] According to the process method of Embodiment 1, the materials are mixed and stirred according to the proportions in Table 3. The mortar was taken from August 4, 2014, as shown in Table 1. Under the load of 30MPa, the concrete pavement bricks of 200mm×100mm×60mm were obtained by pressing. The recycled aggregate of cement concrete waste comes from a recycled construction waste crushing plant in Hong Kong, with an apparent density of 2634kg / m 3 (Aggregate size is 5-10mm) and 2625kg / m 3 (Aggregate size is less than 5mm), water absorption rate is 8.80% (aggregate size is 5-10mm) and 15.80% (aggregate size is less than 5mm), impurity content is 0.2% (aggregate size is 5-10mm) ) And 3.5% (the aggregate particle size is less than 5mm). The natural aggregates are granite and river sand, the apparent density is 2790kg / m 3 (Granite grain size is 5-10mm) and 2657kg / m 3 (The grain size of river sand is less than 5mm), the ...

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Abstract

The invention discloses a method for preparing a regenerative building material product from cement concrete waste. The method comprises the following steps that 1, the water content of mortar in a setting pond of a cement concrete mixing plant is controlled to be lower than 53.0 wt%, and the mortar is prepared into slurry; 2, the prepared slurry is mixed with at least one of regenerative cement concrete waste aggregates and natural cement concrete waste aggregates and optional cement to be uniform, and the mixture is molded; 3, the water content of a molded product is controlled to be lower than 11.0 wt%; 4, carbon dioxide curing is conducted, so that the molded product obtained in the step 3 makes contact with carbon dioxide gas to obtain the regenerative building material product. According to the method, the content of the cement concrete mixing plant mortar in the molded product exceeds 30 wt%, the utilization rate of the regenerative concrete waste aggregates can reach 100 wt%, the product has the advantages of being high in concrete waste utilization rate and production speed, good in performance and the like, and the regenerative building material product has the quite high environmental protection advantage and has good application and popularization prospects.

Description

Technical field [0001] The invention belongs to the field of building materials, and specifically relates to a method for preparing recycled building material products from cement concrete waste. Background technique [0002] According to statistics, the current annual use of commercial concrete in the world exceeds 1 billion cubic meters. Such a large amount of concrete will inevitably produce a large amount of cement concrete waste during its production and supply and future maintenance, reconstruction and demolition, which will have a huge impact on the environment and energy consumption. [0003] In the process of concrete production and supply, because the construction unit has sufficient demand or the already supplied concrete cannot be constructed for other reasons, a large amount of surplus and residual fresh concrete waste will be generated. In Hong Kong, the surplus and residual new concrete waste of commercial concrete mixing plants is about 1.5% of the total commercial...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/00C04B40/00C04B18/16
CPCY02W30/91
Inventor 潘智生占宝剑玄东兴
Owner THE HONG KONG POLYTECHNIC UNIV