Evaluation of resistance properties and moisture sensitivity of modified foamed asphalt mix with micro lime and cement

Today, using cold recycling in situ, as an economical way to improve the road, has grown substantially. Among various ways of cold-in-place recycling, the foamed asphalt technology is considered foremost for its ease and rapidity of implementation. In this paper hydrated lime, cement and micro lime and combination of them were used as active filler in the foamed asphalt mix and degree of influence of active fillers on mechanical properties and moisture sensitivity were investigated. The samples were prepared with bitumen 1, 2 and 3%, and different curing methods (dry and soaked) were tested by the Marshall stability, indirect tensile strength and resilient modulus. The results of this research show that, with increasing the amount of foamed bitumen from 1% to 3%, the Marshall stability and the resilient modulus initially increase and then decrease, but the indirect tensile strength increases continuously. Among the fillers used, the composition of micro-lime with cement had the greatest effect on increasing mechanical properties. For example, this filler increased the Marshall stability and the resilient modulus of samples with 2% bitumen in dry curing method by 47% and 62%, respectively. Also, the cement and micro lime had tremendous effect on reducing moisture damage and increasing the TSR ratio. Finally, by using the results of the paper, a regression model was presented between the result of indirect tensile strength, the Marshall stability and the resilient modulus in dry condition curing.