Experimental Investigation of Punching Shear Behavior in RC Flat Slabs Strengthened with Micro Polypropylene Fibers

摘要

This research is presenting a streng thening technique for increasing punching shear resistance in reinforced concrete two way flat slabs using different concrete mix with different ratios of high performance micro polypropylene fibers as an additive. Sixteen experimental tests have been performed for the selected model. The influence of different ratios of fiber (i.e.; 6, 7.5 and 9 percent of cement weight) on the behaviorof two way solid slabs with three-different specified compressive concrete strengths (i.e.; 20, 30 and 40 MPa) with constant ratio of steel reinforcement has been investigated. A square (2.5 m × 2.5 m) two way flat slab models subjected to concentric compression load has been chosen for such investigation. Results obtained showed considerable increase in the punching load capacity for two way slabs when 9 per cent polypropylene fibers is used compared to medium to low effects when using lower ratios. However, using polypropylene fibers as additives have shown significant effect on deformability.