Fiber-reinforced mortar for secondary roofing slabs

This study investigates the feasibility of completely replacing traditional mesh reinforcement with non-corrodible fiber-reinforced mortar (FRM) in secondary roofing slabs. Patch-load tests were conducted on 36 secondary roofing slabs containing mesh reinforcement, FRM with polyester or structural synthetic fibers only, or a combination of these. The ferrocement specimens carried the highest load but failed due to the sudden rupture of the steel mesh. The slabs with only polyester fibers experienced a brittle failure with low load-carrying capacity. On the other hand, the specimens containing only structural synthetic fibers achieved the requisite residual load-carrying capacity for secondary roofing slabs and also exhibited enhanced ductility through high flexural toughness, thereby sustaining large deflections. This study demonstrates that slabs with structural synthetic fibers alone are sufficient for practical application. The results from the test program were analyzed using yield line theory, based on the stress-strain relation for FRM recommended by the fib Model Code 2010. The first crack and residual load-carrying capacities of the slabs were estimated with reasonable accuracy, thereby providing an analytical basis to predict the behavior of secondary roofing slabs.