Slabs with fibre-reinforced polymers

Recent concerns on the adverse effects of steel corrosion have prompted the use of noncorroding materials, such as Fibre-Reinforced Polymers (FRPs), as alternative to reinforce concrete slabs. To successfully implement FRP reinforcement in slab construction, it is necessary to understand the advantages and limitations of FRP as well as which materials work and which shapes or forms suit best a given application. Compared to ordinary steel reinforcement, FRP reinforcements display a lower stiffness, usually have a lower bond strength, and rupture in brittle fashion. Some FRP products even have a tendency to creep rupture. The effect of these distinctive features on the structural behaviour of concrete slabs have been just partially identified: the effect of the reduced stiffness and bond strength of FRP rebars and grids on the evaluation of average curvatures and average strains to calculate deflections in slabs is relatively well understood; however, the effects of these properties on the interactive relationship between crack widths and FRP strains at cracks have not been examined in detail. As far as shear design of one- and two-way slabs with FRP rebars and grids is concerned, existing design guidelines are mostly empirical and tests scarce. In regards to slab strengthening with FRP sheets, there is a need to study the feasibility of bonding FRP sheets to the slab surface as a rehabilitation vehicle.; This study examines numerous aspects of the flexural, shear and deformation behaviour of one-way and column-supported two-way concrete slabs reinforced with FRP bars, grids and sheets. The study identifies the conditions under which FRP deformed bars, 2-D grids and sheets are either beneficial or detrimental when used either as internal or external slab reinforcement. Design provisions are proposed to control cracks and deflections in one-way slabs with internal FRP rebars or grids, and to evaluate the punching shear capacity of column-supported slabs reinforced with FRP rebars, grids or sheets.