Analysis of Punching Shear Capacity of RC Flat Slabs Produced with Partial Replacement of Cement by Pulverized Fly Ash (PFA)

Flat slab is widely constructed in modern buildings to achieve maximum space utilization. The design of flat slab system for punching shear in various Codes is based on empirical equations as the actual behavior of punching shear is still not well understood. At the same time, the practical applications of the sustainable concrete mixes in structural concrete production are also growing. Pulverized fly ashes (PFA) and other supplementary cementitious material are widely used in concrete to offset the cost of concrete and its environmental impacts. Limited research data is available about the punching shear capacity of the flat RC slabs, incorporating PFA. In this research, four flat slabs were tested such that one flat slab was cast from normal concrete with no PFA and the remaining 3 slabs were cast with 10, 20 and 30% replacement of cement by PFA. Experimental punching shear results were compared with the nominal capacities proposed by BS 8110, BS EN1992-1-1/EC2 and ACI 318. It was found that the estimates of ACI318 and BS 8110 for nominal punching shear capacities are close to the experimental results and the estimates of BS EN 1992-1-1 are conservative.