Modified Marshall test assessment for emulsified asphalt cold mixes

Abstract

Asphalt cold mixes are attractive to transportation agencies for their simplicity in set-up, less energy requirement, ease of application, and environmentally friendliness, though it suffers setbacks in terms of lack of a universally acceptable mix campaign, high water susceptibility, and low mechanical strength at initial stages of construction. However, they are widely used for rehabilitation and maintenance works, and to a lesser extent construction in low-trafficked roads. Notable among the cold mixtures is polymer modified emulsified asphalt micro-surfacing, which is used as a thin non-structural layer for the restoration of skid resistance and waterproofing. Marshall test is used to assess its performance similar to a structural wearing course layer. This study assessed the mechanical performance of cold mixtures by a modified Marshall mix employing a low viscosity cationic quick set emulsion (CQS-1h) and a cationic rapid set emulsion (RS-1k) and a 60/70 penetration grade binder. Rheological criteria assessment was conducted on both emulsions including particle charge, residue by evaporation, settlement and storage stability, solubility in inorganic solvent sieve test, and Saybolt Furol viscosity, while the residue from evaporation was tested for microstructural and mechanical performance, 65% and 63% residue by evaporation, dissolved in trichloroethylene at 95% and 100% for CQS-1h and RS-1k respectively.