Investigation on Pre-cracked RC Slab Strengthening in Flexure Region Under Patch Loading by CFRP

Reinforced concrete (RC) slabs may often experience deficiency due to steel corrosion, temperature effect, increased live loads, fatigue cracking by impact loading, variation in utilizations, a mistake in design and calculation, and error in construction. Carbon Fiber Reinforced Polymer (CFRP) is one of the most important, effective, potential, and advanced composite materials for retrofitting and strengthening metal structures. The objective of this research is to investigate the structural strength and behaviour of CFRP-strengthened RC slabs subjected to patch loading. A series of tests have been conducted on RC slabs which are strengthened by CFRP. Sixteen RC slabs including two reference specimens and CFRP-strengthened specimens were tested in this study. The specimens of the reinforced concrete (RC) slabs were cast with dimensions of 1050 × 700 × 75 mm. Different lengths and configurations of CFRP strips are placed along the slabs. Hydraulic contorted universal testing machine were used for patch loading. The collapse loads, collapse modes, and the load-deformation behaviour of the reference specimen and CFRP strengthen specimen are also presented in this paper. Strengthening of pre-cracked RC slabs at flexural region using CFRP provided better performance than reference slab. Based on test results, it was found that the structural performance of CFRP strengthening pre-cracked RC slab including deflection, and stiffness cracking load is more significant than reference RC slab. The flexural capacity load carrying capacity as well as serviceability improved significantly and varied for different strengthening techniques. Therefore, it can be concluded that better performance can be attained by CFRP strengthening in the flexural region damaged RC slab with the appropriate technique.