Impacts of Laboratory Curing Condition on Indirect Tensile Strength of Cold In-place Recycling Mixtures using Foamed Asphalt

摘要

Cold in-place recycling (CIR) layer is normally covered by a wearing surface in order to protect it from water ingress and traffic abrasion while obtaining the required pavement structure and texture. Currently, various agencies have differing moisture content requirements prior to placement of the wearing surface based either on the total moisture content in the mixture or the increase in moisture content from the pavement prior to recycling. The industry standard for this curing time is 10 to 14 days or a maximum moisture content of 1.5 percent. The main objective of this research is to develop technically sound methods to identify minimum in-place CIR properties necessary to permit placement of the HMA overlay through die laboratory curing process. Indirect tensile strength and moisture content of CIR mixtures were measured from the specimens with two different curing procedures: uncovered and semi-covered. Based upon the limited test results, both the length of the curing time and the moisture content significantly affect the indirect tensile strength of the CIR mixtures. It should be noted that, given a similar moisture level, the longer curing period would produce the higher indirect tensile strength.