Flexural behaviour of precast, prestressed ribbed RPC bottom panels

This study introduces a new type of precast, prestressed reactive powder concrete (RPC) bottom panel for a large-span composite slab. The bottom panels, which have one or two inverted ribs with openings, act as formwork during the construction stage. The paper experimentally investigated the crack characteristics, deflection, and normal section bearing capacity of four precast, prestressed ribbed RPC bottom panels under flexural load. The results indicated that the RPC ultimate strain under non-uniform compression is 5500×10-6 and the plastic influence coefficient of the section modulus is linear with the longitudinal reinforcement ratio. The tensile stress of RPC at the cracked section should be considered while calculating the flexural stiffness; the equation used to determine the nominal tensile stress of RPC as a major variable for calculating the crack width at the bottom of panels was proposed. The bottom panels generally exhibit an over-reinforced failure mode behaviour without the composite layer; the calculation method of the normal section bearing capacity of this mode was established.