Experimental study on the compressive strength and shrinkage of concrete containing fly ash and ground granulated blast-furnace slag

摘要

This paper presents an experimental investigation on the compressive strength and shrinkage (drying shrinkage and plastic shrinkage) property of concrete specimens with fly ash (FA) and ground granulated blast-furnace slag (GGBS), and moreover, the content level and curing age were considered in this experiment. The results show that the addition of FA and GGBS has a significant effect on the compressive strength and shrinkage properties of concrete. It indicated that the compressive strength of specimens decreases gradually due to the reduction of cement hydration products, when the curing age is less than 14 days. Nevertheless, once the curing time exceeds 7 days, the compressive strength increases initially and then decreases. Similarly, the compressive strength of concrete with GGBS increases slightly at first and then decreases, when the content level exceeds the critical value. The variety rule of plastic shrinkage cracks with FA and GGBS is similar to that of compressive strength; however, the variety rule of drying shrinkage strain is contrary to the above experimental results. Furthermore, in the early stage of curing, the GGBS is the main factor on improving strength and drying shrinkage properties, though for the later stage, the FA becomes the main factor instead of GGBS.