Mechanical Analysis Of Continuously Reinforced Concrete Pavements Using Basalt Fiber Reinforced Polymer Bars Considering Punchout

Using Basalt Fiber Reinforced Polymer bars(BFRP bars) to substitute for conventional steel reinforcing bars in Continuously Reinforced Concrete Pavements(CRCP) is a new kind of pavement structure, which has the advantage of saving steel, corrosion prevention and environmental conservation. Punchout is the main damage of CRCP, and narrow crack spacing, deteriorated transverse crack and void under concrete slab are three main factors resulting in punchout. For the convenient of promoting and applying CRCP using BFRP, it is urgent to study mechanical condition of CRCP using BFRP based on punchout, which could provide a reference to reasonable CRCP using BFRP design method and has an important practical meaning.In this paper, conhesive element(shear stiffness of transverse cracks is used to simulate the different conditions of aggregate interlocking) is used to simulate both the normal and the tangential contact relations of transverse cracks. Void under concrete slab is settled to build a finite element model to simulate traffic loads on CRCP using BFRP based on mechanism of punchout by ABAQUS. The influences of the spacing of transverse cracks and the void size on mechanical status and LTE at transverse cracks of concrete slab in CRCP using BFRP are discussed. Sensitivity analysis of mechanical response on slab in CRCP using BFRP is conducted for both the fully support condition and void under concrete slab condition. The effect of different shear stiffness on mechanical response on slab in CRCP using BFRP is discussed.The results show that the maximum tensile stress on the top of the loading slab and the maximum vertical displacement of the loading slab increase,and the LTE at transverse cracks decrease with the decrease of the spacing of transverse cracks. Narrow spacing of transverse cracks may cause the larger tensile stress on the top of the loading slab and vertical displacement of the loading slab, and the worse LTE so that punchout is more likely to occur.With the increase of the width of void area, the maximum tensile stress on the top of the loading slab firstly increases and then decreases. The maximum vertical displacement of the loading slab increases with the increase of the width of void area, and the growth rate is firstly fast and then slowly. The width of void area affects LTE significantly and LTE decreases rapidly with the width of void area increasing. Void under concrete slab makes mechanical condition of concrete slab worse and punchout could be prevented when support condition under slab is good.The results of sensitivity analysis show the increase of the thickness of concrete slab could improve mechanical condition of concrete slab significantly and the increase of concrete elasticity modulus, base elasticity modulus, BFRP bars elasticity modulus and its percentage of longitudinal reinforcement could slightly improve mechanical condition of concrete slab. Even though the maximum vertical displacement of the loading slab decreases with the increase of foundation modulus, but LTE also decreases significantly which could cause more damage of concrete slab near transverse cracks in CRCP using BFRP. The transverse cracks have high load transfer efficiency(LTE) due to effective aggregate interlock as shear stiffness of transverse cracks increases and mechanical condition of concrete slab will be improved significantly.