Strength Prediction of Cold Asphalt Emulsion Mixtures Using the Maturity Method

Abstract

The lack of universal design standards for cold mix asphalt (CMA) has led to the use of laboratory–field correlation techniques to predict its strength. Such techniques disregard the gradual strength increase in CMA with curing time and temperature. This study developed strength–maturity functions to predict CMA strength. Virgin and recycled aggregates from reclaimed asphalt pavement (RAP) were considered. Specimens 100 mm in diameter and 63.5 mm in thickness were produced using the Marshall method. These were subjected to isothermal curing regimes and measured for indirect tensile strength. The early-age strength of the RAP mix cured at low temperatures of 25°C was lower than that of the virgin mix. However, after curing for 18 days, there was no significant difference in strength between the virgin and RAP mixes for all temperature regimes. Asphalt made from RAP mix had a higher temperature sensitivity factor (B) than that of the virgin mix. A linear–parabolic strength–maturity function predicted the strength of cold asphalt emulsion mixtures (CAEMs) with an accuracy greater than 95%. Thus, the proposed maturity method effectively predicts the strength of CAEMs.