A study of proportioning techniques for SCC with crushed aggregate

This paper presents a new approach to proportioning of self-compacting concrete (SCC) with crushed aggregates. In this new approach, the conventional grading model for continuous packing was modified taking into account the difference in grain shape between crushed and natural aggregates, and the specific area of fine materials measured by the BET method was used for calculating the need of additional water for lubrication of fine particles. The results from four trial mixes show that this additional water is corresponding to 30-60 molecular layers. This water may not be contributed to the conventional water-cement hydration system, implying that the effective water-cement ratio is significantly lower than the apparent watercementratio