A Study on Cold Laid Microsurfacing Containing Water-Based Epoxy-Modified Bitumen Emulsion

Pavement maintenance is significant to maintain an efficient and safe operation of the road network and meet the need of the drivers and their vehicles. The soundness of the pavement layers affects the overall performance of the pavement, with surface course being the layer that requires high quality materials to withstand direct contact with repeated traffic loading in all weather conditions. Surface treatments are a common maintenance measure to maintain serviceability, safety, and pavement longevity. In this paper, a surface treatment named cold microsurfacing containing water-based epoxy-modified bitumen emulsion (WEB), a more eco-friendly and cost-effective material than conventional microsurfacing, is studied in the laboratory. Three laboratory tests were conducted to characterise microsurfacing: sand patch test, pendulum test and indirect tensile strength test (IDT). Volumetric properties and microscopic analysis of the compacted specimens using a digital microscope are also shown. The results showed that unmodified bitumen emulsion samples had higher air void content (%) than WEB samples and higher mass loss. Overall, WEB samples exhibited fluctuating curing rates although storing conditions were similar to all tested samples. Voids filled with asphalt (VFA) (%) and voids in mineral aggregate (VMA) (%) were higher for unmodified bitumen emulsion samples and VFA results from all samples indicated an equally effective coating of aggregates. WEB samples exhibited better skid resistance characteristics and greater braking resistance than unmodified bitumen emulsion samples. IDT strength tests were comparable for all samples