Experimental and statistical investigation of self-consolidating concrete mixture constituents for prestressed bridge girder fabrication

Self-consolidating concrete (SCC) has the potential to increase precast production and quality, especially for production of prestressed concrete (PSC) bridge girders due to its superior workability compared with conventional concrete (CC). To obtain desired fresh and hardened properties for the production of SCC PSC girders, many factors related to material characteristics and mixture proportioning must be considered. An experimental comparison of fresh and hardened properties of SCC mixtures made with different material constituents was conducted in this study. The ultimate objective of this paper is not only to provide an experimental program enabling the investigation of the effect of material constituents on the performance of SCC mixtures but also to gain more knowledge for improved production of SCC PSC girders. The experimental program was established based on technical findings from a literature review and additional input from a survey of several state departments of transportation (DOTs). The mixture constituents used to investigate SCC performance consisted of the type of cement and size and type of coarse aggregate. Testing methods included slump flow, visual stability index (VSI), J-ring, column segregation, and compressive strength. The testing results showed that the type, shape, and size of coarse aggregate have a dominant effect in terms of fresh properties and compressive strength; specifically, mixtures with river gravel had larger spreads than mixtures with crushed limestone. Cement type had the expected effect with mixtures using Type III cement developing higher early strength than those using Type I/II cement. A statistical analysis was performed to determine significant mixture parameters in terms of fresh and hardened properties. It was found that the fine aggregate content was the most significant parameter affecting both fresh and hardened properties' behavior.