Laboratory performance-based evaluation of cold bituminous mixtures for patching applications

A flexible pavement under repeated loading cycles and environmental conditions is subjected to progressive deterioration and aging. For local roads, two of the main surface distresses on bituminous pavement are raveling and localized depression which lead rapidly to potholes. Since these localized-hazardous failures compromise safety and pavement serviceability, they must be repaired as soon as they occur. Usually, the temporary rehabilitation of local roads subjected to potholes is managed by public administration as emergency treatment or planned maintenance, by using cold bituminous mixtures that are often not able to guarantee a long-lasting pavement repair. In this sense, innovative and high-performance cold bituminous mixtures have been recently optimized, replacing the traditionally used bituminous emulsion with special bitumen, resins, anti-stripping agents and several additional ingredients. The aim of this research project was to improve the knowledge of these products used for patching operations and the proposal of an overall testing protocol able to characterize high-performance cold bituminous mixtures using test procedures and parameters similar to those used for hot mix asphalt. The results showed that the tested material guarantees, under specific curing time and test temperature, higher performance than traditional cold bituminous mixtures and that the proposed test procedure can be used for the evaluation of such high-performance products.