Horizontal Cracking in Continuously Reinforced Concrete Pavements

Severe spalling and half-depth punchout failures associated with horizontal cracks at the mid-depth of concrete slabs were observed in continuously reinforced concrete pavement (CRCP). To identify the causes of those horizontal cracks, field observations, laboratory tests, and numerical analyses were conducted. The extent of horizontal cracking in the concrete slab was investigated with coring. Several variables relative to design, material, and environment were considered in the field and laboratory studies to evaluate possible causes of horizontal cracking. Numerical models of CRCP were developed using the finite element discretization, and the shear and normal tensile stress distributions in CRCP were investigated with the models to verify the results obtained from the field and laboratory studies. Numerical analysis results show that maximum shear and normal tensile stresses develop near the depth of steel bars at transverse cracks. Evaluations of in-place concrete material properties, such as modulus of elasticity and thermal expansion coefficient, from sections with and without horizontal cracks and environmental conditions during construction, all support the results of the numerical analysis.