Flexural strength of polyester fiber reinforced hybrid ferrocement hollow slabs

Abstract

An analytical model was developed for the flexural strength of hybrid ferrocement hollow slabs cast with alkali resistant polyester fibers mixed in the cement mortar matrix and was validated by the experimental results. Fifteen ferrocement hollow slabs of 2m span were cast and tested in this investigation. The slabs were subjected to one way cyclic loading by applying two line loads at one-third span and tested under simply supported condition and the ultimate moment of the slab was determined experimentally. The “all tensile reinforcement yielding method” was used to determine the flexural strength of the hybrid slabs analytically. The short discontinuous fibers introduced in the cement mortar matrix act as secondary reinforcement reducing the propagation of cracks by the bridging forces. The bridging force contributed by the polyester fibers in the cement mortar matrix was taken into account for the calculation of the depth of the compressive stress block. Also a modification factor ‘v’ (nu) was introduced to find the compression force in the stress block. The flexural strength of the hybrid slabs was found taking into account the bridging forces of the fibers in the tensile zone. The analytical results of the flexural strength of the hybrid slabs are close to the experimental values and it is established that the value of the factor ‘ν’ is validated.