A Bitumen-Stabilized Base Course as a Pavement Overlay Anti-reflective Cracking Solution

The Port of Rio Grande is located in the city of Rio Grande in Rio Grande do Sul, the southernmost state of Brazil. To access the port, a concrete pavement was built in 1975. Afterward, an overlay of asphalt concrete was added on top of the concrete pavement. In 2019, an experimental section was built using a gap-graded asphalt wearing course over a permeable cold bituminous emulsion mix (CBEM) with the objective of reducing crack reflection. This research aims at evaluating the performance of the bitumen-stabilized base and determine its effectiveness in mitigating crack propagation. The experimental program included the analysis of available data from pavement monitoring, such as deflections and surface conditions, in order to estimate the in situ modulus and the progression of rutting and cracking throughout a certain period. The number of equivalent single axle loads (ESALs) was computed through the data files from the surveys conducted over a three-day period. The deflection analysis revealed that the bitumen-stabilized layers maintained their structural integrity when employed as an overlay on rigid pavement. There were no indications of significant elastic deformation or rutting. The surface conditions indicated that the asphalt wearing course over the CBEM base displayed minor cracking three years post-construction. This suggests that employing such open-graded bitumen-stabilized mixes effectively postpones the propagation of cracks.