Experimental study on preparation of high strength lightweight aggregate concrete by combined admixture of fly ash and mineral powder

摘要

Fly ash and mineral powder are used for composite preparation of high strength lightweight aggregate concrete in this paper, and NEL diffusion-coefficient and SEM are applied to study the concrete performance. The results show that the high strength lightweight aggregate concrete prepared with fly ash mixed with mineral powder has very good workability and higher strength. Excellent composite effect is shown when fly ash and mineral powder are combined together, the pozzolanic reaction more fully and the interface transition region between the lightweight aggregate and the cement paste solidifies further, which makes the structure of the lightweight aggregate concrete more compact. Hence, the strength and anti-permeability performance of the lightweight aggregate concrete are both improved. In addition, the new type concrete presents outstanding chlorine ion anti-permeability performance and its 28d permeability coefficients of chlorine ion are less than 121×10− 14m2/s. In conclusion, the combined admixture of fly ash and mineral powder not only shows the excellent comprehensive effects but also saves energy, protects environment and reduces costs.