Analysis of Shrinkage and Thermal Stresses in Concrete Slabs Reinforced with GFRP Rebars

Abstract

The corrosion resistance of glass-fiber-reinforced polymer (GFRP) rebars makes them a promising substitute for conventional steel reinforcing rebars in continuously reinforced concrete pavements (CRCPs). Studies are conducted concerning the effect of using GFRP rebars as reinforcement in CRCP on the concrete stress development, which is directly related to the concrete crack formation that is inevitable in CRCP. In this study, an analytical model of a freely supported reinforced concrete slab is first developed to simulate the shrinkage and thermal stress distributions in concrete owing to the restraint provided by GFRP rebars in comparison with the stresses induced by steel rebars. The results show that the stress level in concrete is reduced with GFRP rebars owing to a low Young’s modulus of GFRP. In addition, the analytical model is utilized to estimate the concrete strain variation in the reinforced concrete slabs resulting from changes in the concrete volume, and the results are compared with the experimental observation. Finite-element (FE) analyses were also conducted to calculate the stress distribution and crack width of a GFRP-reinforced CRCP section subjected to both the concrete shrinkage and thermal change. By using the FE method, the crack spacing and crack width of a CRCP reinforced with GFRP rebars were predicted and compared with those of a steel-reinforced CRCP. The result shows that the crack spacing and the crack width of the GFRP-CRCP are larger than those of the steel-CRCP.