Preparation method of modified recycled coarse aggregate

Abstract

The invention discloses a preparation method of modified recycled coarse aggregate. The preparation method comprises the following steps of: soaking a recycled coarse aggregate obtained by crushing and screening waste concrete in clear water, cleaning and airing the recycled coarse aggregate; fully soaking the recycled coarse aggregate into a silicon slag emulsion, adding limestone powder into thesilicon slag emulsion, performing continuous stirring, and uniformly mixing the limestone powder with the silicon slag emulsion; and further performing slow stirring for a period of time, fishing outthe recycled coarse aggregate, and naturally draining the recycled coarse aggregate to obtain the modified recycled coarse aggregate. The silicon slag emulsion is a non-layered mixed solution obtained by ultrasonically dispersing acidic silicon slag particles with recovered zirconium in water uniformly. The silicon slag emulsion is utilized to modify the recycled coarse aggregate, and therefore,the moisture absorption of the recycled coarse aggregate can be reduced, and the water absorptivity of the recycled coarse aggregate can be lowered; meanwhile, when the modified recycled coarse aggregate is used for preparing recycled concrete, the early strength and the mechanical property of the concrete are improved. The method is simple in operation process and low in cost, and has very high economic value and application value.

Description

technical field [0001] The invention relates to the field of building materials, in particular to a preparation method of modified recycled coarse aggregate. [0002] technical background [0003] In recent years, with the further development of my country's urbanization process and the gradual renewal of cities, the demolition and reconstruction of original buildings in urban construction such as shed reform, roads, and bridges has produced a large amount of construction waste. However, most of the construction waste is transported to the suburbs or around the city for simple landfill or open storage without any treatment, which not only wastes land and resources, but also pollutes the environment; on the other hand, with the increasing population, The demand for sand and gravel aggregates in the construction industry continues to grow. For a long time, because sand and gravel aggregates are widely available and cheap, they are considered inexhaustible raw materials and hav...

AI Technical Summary

Problems solved by technology

Mainly include: (1) By means of carbonization, relying on the generated calcium carbonate to fill the gaps and cracks to reduce water absorption, but due to the limited content of calcium dioxide in the recycled aggregate, it is difficult to realize the microbes without external alkali supplementation. Complete and effective filling of cracks; (2) Use slag, fly ash, silica or nano-silica particles and other substances with pozzolanic activity for infiltration filling and pozzolanic reaction. This method can effectively improve the final strength of concrete, but Since the active material can only exert its maximum activity under the condition of adding cement to form a concrete mixture, the water absorption of the recycled aggregate cannot be significantly reduced; The microbial enzymatic reaction generates carbonate ions, which then react with calcium ions in the recycled aggregate to generate calcium carbonate, thereby filling microcracks and improving the physical properties of the recycled aggregate.

However, due to the influence of living conditions, microorganisms cannot completely fill the microcracks effectively and completely, and the effect of reducing the water absorption of recycled aggregates is poor, resulting in a large amount of water in the concrete mixture, which affects the final strength.

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