Dense paste premixing method for improving properties of building garbage recycled aggregate concrete

Abstract

The invention discloses a dense paste premixing method for improving the properties of a building garbage recycled aggregate concrete. According to a set preparing ratio, a part of cement and a part of water are premixed, forming a dense paste; and then, recycled coarse aggregates are added and mixed, and a dense paste wrapped material is formed after full and uniform stirring. At the same time, after a mixed dry material is obtained by mixing and stirring the rest of cement and recycled fine aggregates, the rest of water is added, and after stirring, premixed mortar is formed; and then, after the dense paste wrapped material and the premixed mortar are mixed and uniformly stirred, the recycled concrete is obtained. The dense paste wrapped material enables the interfaces of the coarse aggregates to be in full contact with the cement paste, so that a cementation function is improved; and the mixed dry material and the premixed mortar can overcome the high water absorption and high viscosity problems of the recycled fine aggregates, the cement fully absorbs the water, and a cement hydration function is promoted. Experimental results show that the properties are obviously better than those of a concrete prepared by a traditional mixing technology.

Description

Technical field [0001] The invention belongs to the field of resource utilization of construction waste, and relates to a premixed thick slurry method for improving the performance of construction waste recycled aggregate concrete. Background technique [0002] Most scholars believe that the surface hardened mortar layer is the most important factor affecting the quality of construction waste recycled aggregates. Because the surface mortar layer contains a large number of pores, the water absorption of the recycled aggregate is much greater than that of natural aggregate. Therefore, when using recycled aggregate to prepare concrete, if the traditional mixing process is used, part of the water is easily absorbed by the recycled aggregate and affects the fullness of the cement. Hydration and hardening weaken the bond strength of cement slurry and aggregate interface. Moreover, due to the large content of clay particles in recycled fine aggregates, traditional mixing techniques are...

AI Technical Summary

Problems solved by technology

Because the surface mortar layer contains a large number of pores, the water absorption of recycled aggregate is much higher than that of natural aggregate. Therefore, when using recycled aggregate to prepare concrete, if the traditional mixing process is used, part of the water is easily absorbed by the recycled aggregate, which affects the fullness of the cement. Hydration hardening weakens the bonding strength of cement slurry and aggregate interface

Moreover, due to the large clay content of recycled fine aggregate, the traditional mixing process is not conducive to improving the fluidity of recycled concrete mixture.

[0003] In addition, compared with natural aggregates, recycled aggregates from construction waste have a high clay content, and most of the surfaces are attached to cement mortar or ash powder. There are many internal cracks, large porosity, and high water absorption, resulting in the mixture of recycled aggregate concrete. Poor workability, poor mechanical properties and durability after hardening

[0004] At present, there are many reports on the mixing process to improve the performance of concrete at home and abroad, but most of them are not suitable for recycled concrete from construction waste.

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