Punchout For Continuously Reinforced Concrete Pavements Using Fiber Reinforced Polymer Rebars

In continuously reinforced concrete pavement, using fiber reinforced polymer bars instead of traditional steel reinforcement can solve punchout problems encountered in air and rain erosion occurs due to corrosion. FRP has better corrosion resistance than the conventional steel, the quality of FRP is lighter, higher strength, smaller elastic modulus, the thermal expansion coefficient is closer to the concrete. FRP is also a poor conductor of electromagnetic. So the use of FRP replace traditional steel has excellent practical value. While it has started to use FRP in concrete pavement, but the design specifications on punchout to be further research and practice.The ultimate tensile strength and elastic modulus of FRP bars are tested by compression experiments, shows that FRP has high strength and low modulus. By the standard cube tests of FRP reinforced concrete and ordinary concrete, using ANSYS finite element fitting compression test process, unanimously the results show that the mechanical properties of FRP reinforced concrete is better than plain concrete. Through taking loading and unloading cycle process for FRP reinforced concrete and ordinary concrete by ANSYS, analyzing its stress-strain relationship, indicating that resistance to fatigue failure capability of FRP is stronger than ordinary concrete. The analysis of the test results and finite element models are pointed out that the use of FRP reinforcement is more appropriate than ordinary in the CRCP.Using ANSYS establish FRP-CRCP model, and analysis the vehicle load of FRP concrete pavement and concrete pavement structural mechanics general response under dynamic loading and static force. The analysis results are as follows: under the effect of dynamic load, the center distance on the vehicle load is smaller, the vertical displacement is larger. At different times under the influence of wheel load, the maximum vertical compressive stress, the maximum shear stress peak, the maximum shear stress in the underly layer and surface layer, the maximum tensile stress in the underly layer in the surface layer increased non-linear with an increasing number of wheel loads. Under the effect of static load, the surface stress, surface of the shear deformation, vertical and horizontal deformation in the two kinds of pavement structure show similar variation, but the all indicators of FRP reinforced concrete pavement are significantly better than ordinary concrete pavement.Punchout is the most common types of failure in CRCP, it is mainly produced in the crack dense areas. By analyzing the punchout produced process and failure mechanism are pointing out the direction of pavement research. Analysis of the factors influencing of punchout in the structure of FRP-CRCP and the change rules of factors, considering the loss of crack load transfer performance over time, the crack spacing varies with time and the cumulative damage of concrete in longitudinal distribution, taking incremental analysis method to establish the punchout damage estimated equation.There is an important significance to elucidate the mechanism of structural changes in the performance and structural damage control method of the FRP-CRCP in the article, which lays the foundation for the establishment and perfection of the design theory of FRP-CRCP.