Laboratory investigation of the mechanical and functional properties of cold mix patching materials

Cold mix patching materials (CMPMs) present an environmentally friendly and sustainable solution for addressing road potholes, particularly during cold and wet weather conditions. While they offer cost effectiveness and reduced ecological impact, CMPMs encounter challenges related to their mechanical and functional performance in practical applications. There is an increasing demand for higher-quality CMPMs, yet their durability tends to be relatively short-lived. This study conducted a comprehensive assessment of various CMPM variants available on the European market, such as solvent-containing mixtures (SC) and membrane containing mixtures (MC). The investigation placed specific emphasis on critical aspects, including stability, workability, raveling, and bonding, employing both conventional and innovative testing methodologies such as Marshall stability, indirect tensile strength, Hubbard-Field stability, indentation stability, Leutner shear bond, locking point, and brush tests conducted across a spectrum of temperatures and compaction pressures. The findings indicated that mixtures with locking points ranging from 40 to 60 exhibited good to excellent workability. MC mixtures generally outperformed SC mixtures, except in terms of bonding properties. Despite achieving air voids of up to 31.7 %, their stabilities exceeded recommended values in the literature. Optimal abrasion resistance was observed with higher compaction pressure (600 kPa) and longer cure time (30 days) working in conjunction. Furthermore, increasing the compaction pressure from 200 kPa to 600 kPa resulted in a two to threefold increase in interlayer shear strength for all products.