An Optimized Mix Design Method for Emulsified Bituminous Mixtures

Cold in place recycling is one of the widely used rehabilitation techniques in different countries. Although many research works have been carried out on these mixes, no universally accepted mix-design method has been proposed for cold-mix recycling. In this research, two mix design methods, namely modified Marshall Method and a proposed mix design method were verified on specific cold mixes. Bulk specific gravity and air voids determination are used in Modified Marshall Method and Indirect Tensile Strength (dry and soaked), Marshall Stability and Tensile Strength Ratio (TSR) were used in the proposed mix design method. Also, two types of active fillers, namely cement and lime, have been substituted with part of the mix filler as the stabilizing agents. The results showed that there are some ambiguities in Modified Marshall method. Results also indicated that with the proposed mix design method, the optimum bitumen emulsion content was lower than the case of modified Marshall Method. However, ITS and Marshall Stability values in proposed method show enhanced properties of the mixes that were designed using the Modified Marshall method.