Design of CRCP Using Glass Fiber Reinforced Polymer Rebars (FHWA-HRT-05-081)
This is Task 3: Continuously Reinforced Concrete Pavement. The corrosion resistance characteristics of glass fiber reinforced polymer (GFRP) rebars make them a promising substitute for conventional steel reinforcing rebars in continuously reinforced concrete pavements (CRCPs). Studies are conducted on the effect of using GFRP rebars as reinforcement in CRCP on concrete stress development, which is directly related to the concrete crack formation that is inevitable in CRCP. Under restrained conditions, concrete volume change because of shrinkage and temperature variations is known to cause early-age cracks in CRCP. In this study, an analytical model has been developed to simulate the shrinkage and thermal stress distributions in concrete due 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 because of a low Young’s modulus of GFRP. In addition, the analytical model has been used to estimate concrete strain variation in reinforced concrete slabs because of changes in concrete volume, and the results were compared with the experimental observation. Finite element (FE) methods are also developed to predict the stress distribution and crack width in the GFRP-reinforced CRCP section that is subjected to the concrete volume changes under various CRCP design considerations, such as the coefficient of thermal expansion (CTE) of concrete, the friction from the pavement’s subbase, and the bond-slip between concrete and reinforcement. Based on the results from the FE simulation along with the mechanistic analysis, a series of feasible designs of the GFRP-reinforced CRCP is proposed. The stress levels in the GFRP reinforcement, the crack widths, and the crack spacings of the proposed pavements are shown to be within the allowable design requirements.
Authors: Jeong-Hoon Choi and Roger H. L. Chen, Ph.D.