Optimization of SCC mix at paste level by using numerical method based on a paste rheological threshold theory

This paper presents a new numerical method to optimize the mix proportion of self-compacting concrete (SCC) at paste level based on a paste rheological threshold theory that the SCC formulated paste must satisfy the criteria to ensure SCC with good flowability and segregation resistance. A total of 12 mini-slump flow tests were initially conducted, and relevant rheological characteristics were derived. The correlation between mixture variables and rheological characteristics was determined using a bilinear interpolation method. A self-compacting area at paste level was defined by choosing the mixture whose rheological characteristics satisfied the criteria. The economical mixture was obtained from the area, and an iteration process was introduced to ensure that the rheological characteristics of this mixture satisfied the criteria. Finally, an optimized SCC mixture from an economical aspect was achieved, and the robustness of the mixture was also analyzed.