Accelerated Pavement Testing Of Extended Life Continuously Reinforced Concrete Pavement Sections

Abstract

Ten CRCP sections were built at the ATREL full-scale testing facility, with five sections being tested under accelerated traffic loading conditions and five sections evaluated for induced transverse cracks. The opening and closing of cracks was measured at several transverse cracks, along with vertical deflections, transverse strains at the top of the slab, and internal pavement temperature. Two procedures were developed to determine crack width from the measurement of crack closing. These procedures used the horizontal deformation caused by changing the vertical load level or temperature condition to determine the in situ crack width. By calibrating the crack width model presented in the mechanistic-empirical pavement design guide (ME-PDG), crack width values obtained under different temperature conditions could be standardized. The model was adapted to predict crack width at any depth in the slab and an enhancement is proposed to use the model for predicting short-term changes in crack width. Continuous surveying of the pavements for more than two years and the sequential application of a large number of rolling-wheel loads on each section allowed for the collection of response data and observation of CRCP failure mechanism. Comparisons are presented regarding the elastic responses in sections with different design features (PCC thickness, steel content, and steel depth). Under conditions of small crack width (less than 0.15 mm), load transfer capacity at the transverse cracks remained intact despite heavy traffic loads and seasonal thermal cycles. Failure of the CRCP sections resulted from permanent deformation in the supporting layers. This report includes evaluation of crack width variability and use of FWD to characterize in situ crack width of field CRC pavements. Recommendations are made for the improvement of CRCP construction based on early age temperature, concrete drying shrinkage, and induction of transverse cracks.