It is difficult and usually complicate to design properly cement concrete mix for pavements because many influencing factors are involved in the entire design and construction process. To design early-strength concrete mix is even more complicated as additional factors have to be considered in the process. There are a large number of laboratory and field experiments currently being conducted in Chongqing Research Institute of Highways, the Minstry of Transportation of China, Chongqing, China, in applying admixtures in cement concrete mix design. This paper focuses on optimal concrete mix design, including the determination of w/c ratio (water over cement in quantity), amount of admixtures, and grading of course aggregate for the cement concrete. Through this research, a special methodology for the concrete mix deign was developed, which is capable of adapting to changeable temperature, environment and climate, surface characters of the course aggregate, and concrete curing time for pavements. In addition, this paper presents new ideas in the design of concrete containing admixtures and in the study of surface characters of the course aggregate. The method is also applicable to the design of ordinary Portland cement concrete. (A)
Abstract