Impact Energy Absorption of Sisal Fiber Reinforced Ferrocement Slab Elements and Its Statistical Relationship with Composite Compressive Strength

Abstract

This study evaluates the level of energy absorption of sisal fiber reinforced ferrocement (SFRFC) slab elements of size 300 mm × 300 mm × 25 mm) (thickness) through low-velocity impact tests. The slabs are reinforced with 2 and 3 layers of steel weld mesh as primary reinforcement; and the sisal fibers of short and long fiber length, S-FL = 20 mm and L-FL = 40 mm (respectively) of varying volume fraction, (FVf of = 0.25–1.00%) act as secondary reinforcement. The compressive, split-tensile strength and flexural strength of hardened sisal fibrous mortar and plain (control) mortar specimens are determined and presented. The initial impact energy absorption (IIEA) and ultimate impact energy absorption (UIEA) of SFRFC slabs were found to be higher than ferrocement (FC-control) slabs (reinforced with 2 and 3 layers of steel mesh) demonstrating the effective contribution of sisal fibers in improving the performance of ferrocement slabs. When the length of the sisal fibers was increased from 20 mm to 40 mm in SFRFC slab elements (in hybrid combinations of steel mesh of 2–3 layers and fiber volume fraction of 0.25–1%), the impact resistance has increased several-fold over FC-control slabs. The composite compressive strength (CCS) of SFRFC has substantially increased when sisal fibers (of short and long fibers) of fiber volume fraction (FVf = 0.25–1%) are added to FC-control slab elements. Statistical prediction models have been developed separately for three dependent variables, IIEA, UIEA and CCS keeping constant the four independent variables, mesh layers (ML), fiber volume fraction (FVf), fiber length (FL) and mortar compressive strength (MCS), and the predicted values matched with the experimental results, within the acceptable error range. This study has statistically established a significant relationship between UIEA and CCS of sisal fiber reinforced ferrocement (SFRFC) slab elements.