Mix design methodology for fibrous self compacting concrete based on compressible packing model (CPM)

Abstract

The development of Self Compacting Concrete (SCC) marks an important milestone in improving the product quality and thus the efficiency of the building industry. Steel Fiber Reinforced Self Compacting Concrete (SFRSCC) combines the benefits of SCC in the fresh state by avoiding cracking and shows an improved performance in the hardened state compared to conventional concrete. The packing density of the aggregates and the fibers of SFRSCC determine the amount of cement paste that is required to fill the interstices of the granular skeleton. In order to predict the packing density of the granular skeleton, the 'Compressible Packing Model' was used and calibrated with the applied materials. In the present work, M20, M40 and M60 grade SCC mixes, without and with steel fiber, were developed using Compressible Packing Model concept. To qualify the Self-Compacting Concrete mixes thus developed, fresh properties like slump flow, J-Ring, V-funnel, L-flow tests were conducted and checked against EFNARC Specifications. The strength of hardened concrete was also tested. A detailed mix design procedure developed using CPM method has been explained in this paper. It was noted that the CPM based optimization of aggregates considers important parameters like wall effect, loosening effect and perturbed volume which are important in deciding the aggregate portion of SCC.