High-strength recycled concrete as well as preparation method and application thereof

Abstract

The invention relates to the technical field of building materials, in particular to high-strength recycled concrete and a preparation method and application thereof, and the high-strength recycled concrete is prepared from the following raw materials in parts by weight: 290 to 443 parts of cement; 20 to 70 parts of fly ash; 20 to 70 parts of slag; 20 to 70 parts of silica fume; 20 to 70 parts of metakaolin; 650 to 750 parts of fine aggregate; 550 to 600 parts of natural coarse aggregate; 450 to 510 parts of recycled coarse aggregate; 4.0 to 7.0 parts of a water reducing agent; and 140 to 160 parts of water. The high-strength recycled concrete is designed and prepared on the basis of the service environment and load-bearing requirements of a recycled concrete structure, and mineral admixtures comprise coal ash, slag, silica fume and metakaolin. According to the preparation method, a pre-wetting-double slurry wrapping method is adopted, the recycled aggregate is subjected to pre-wetting, slurry wrapping and repeated stirring treatment, the internal microstructure of the concrete is enhanced, and the mechanical property of the recycled concrete and the durability of the recycled concrete in a composite salt erosion environment are improved.

Description

Technical field [0001] The invention relates to the technical field of building materials, specifically a high-strength recycled concrete and its preparation method and application. Background technique [0002] In the past 10 years, a large amount of waste concrete has been produced in the process of urbanization in my country. As of 2017, the total amount of waste concrete produced in mainland my country was 1.16 billion tons, growing at an annual rate of 5-10%, and is expected to reach 1.7 billion tons by 2020. ; At present, the main methods of disposal of waste concrete in our country are stacking and landfilling, which seriously pollutes the fragile ecological environment. Therefore, by using waste concrete to produce recycled aggregate and use it to prepare new concrete (recycled concrete), it will promote the recycling of waste concrete. It is of great value; in recent years, with the strong support of various provinces and cities in my country, recycled concrete has gr...

AI Technical Summary

Problems solved by technology

At present, considering the service environment and structural load-bearing requirements of recycled concrete in Northwest my country, the mix ratio design and preparation of recycled concrete with strength grade C20 can no longer meet the engineering requirements, so it is necessary to prepare high-performance recycled concrete with higher strength grade; In the process of actually preparing recycled concrete, the combination of mineral admixtures and the difference in the proportion of the admixture often directly affect the final performance of recycled concrete. In the existing technology and research, most of the mineral admixtures are pulverized coal ash, slag and silica fume, and the combination method is relatively single (mostly single-mixed and double-mixed), which cannot maximize the performance improvement effect of mineral admixtures on recycled concrete; finally, regarding the existing improvement technology of recycled concrete preparation methods, All are simple improvements on traditional mixing methods (such as double and triple mixing methods), and the preparation process is not detailed and comprehensive enough.

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