The present study includes an experimental investigation of the behavior of simply supported lightweight aggregate concrete (LWAC) and normal weight concrete (NWC) square slabs reinforced by different ratios of carbon fiber reinforced polymer (CFRP) and/or steel bars reinforcement. The experimental program consists of testing nine two-way reinforced concrete square slab models under uniformly distributed load (UDL). They were of the same overall dimensions, (1050×1050×80) mm. The main variables considered in the experimental study are: type of concrete; LWAC or NWC, type of reinforcement; steel, CFRP and hybrid (steel and CFRP) bars with different ratios and arrangements, the behavior of slabs with bottom and top CFRP bars reinforcement and the efficiency of using CFRP bars for strengthening slabs in two directions by using near surface mounted (NSM) technique. In this study, a waste of clay bricks was used as a coarse lightweight aggregate (CLWA) to produce structural lightweight aggregate concrete (SLWAC).
It was found that LWAC slab model reinforced by CFRP bars has a lower total weight by amount 20% in comparison with NWC slab model reinforced by CFRP bars with rather a small reduction in slab ultimate load capacity by amount not more than 6.5%. However, it was found that the CFRP reinforced LWAC slab model can achieve ultimate load capacity higher than equivalent steel reinforced LWAC slab model by about 34.62%. NSM technique by CFRP bars in two directions of LWAC slab is very effective and nearly provided the same efficiency of equivalent internal reinforcement.