Experimental study of filling capacity of self-compacting concrete and its influence on the properties of rock-filled concrete

Rock-filled concrete (RFC) was developed in China mainly for large-scale concrete construction. The distinctive casting procedure of RFC makes it highly dependent on the filling capacity of self-compacting concrete (SCC). This study investigated two of the most controversial issues regarding RFC—the filling performance of SCC and the large interface between SCC and rocks. These issues were examined through an experimental setup designed to stimulate SCC flow in rock skeleton. The effects of different factors (aggregate size, yield stress, etc.) on the filling capacity of SCC and the properties of RFC were investigated on the basis of filling rate, cross-section porosity, and interface microstructure. Two clogging mechanisms were summarized from literature and used to explain the experimental results. The findings indicate that the interface microstructure of RFC greatly depends on the filling performance of SCC which is significantly affected by the size and condition of the large rocks.