Evaluation of crack width in roller-compacted concrete pavement

Crack width is a critical factor influencing the behaviour and performance of a roller-compacted concrete pavement (RCCP) because wide cracks can result in water infiltration and poor load transfer, leading to faulting, excessive deflection and further cracking. The crack width may be affected by temperature changes, concrete drying shrinkage and creep, crack spacing and the base material. An empirical equation to predict the crack width has been proposed by the American Association of State Highway and Transportation Officials (Aashto). However, this equation is quite simplified because a uniform strain distribution is assumed along the slab length. In this work, a mechanistic approach to predict the crack width in RCCP was developed using a three-dimensional finite-element model considering a non-linear friction model between the slab and the base. Moreover, the effect of concrete creep on the crack width was incorporated using the effective modulus method. The mechanistic model was validated with crack width data from two full-scale RCCP test sections in South Korea. The mechanistic model showed good agreement with the field data, whereas the Aashto equation tended to over-predict the crack widths. The proposed model is thus helpful to predict the crack width in a concrete pavement slab for given environmental conditions, slab geometry, material properties and base material.