Effects of various additives on the moisture damage sensitivity of asphalt mixtures

Effects of four additives, namely two fatty amine (Wetfix I, Lilamin VP 75P), one catalyst (Chemcrete) and a polymer (rubber), on the moisture damage of asphalt mixtures were studied. Rheological characteristics of the binders were measured using conventional methods both original and thin-film oven aged. Mechanical characteristics of the mixtures were evaluated with Marshall, indirect tensile and Lottman treatment tests. The additives used in this study reduced the level of damage due to moisture in asphalt mixtures. Minimum acceptable indirect tensile strength ratio (0.70) is achieved when Chemcrete and 0.2% of Wetfix I, and 0.4-0.6% of Lilamin VP 75P are used in asphalt mixtures. Indirect tensile strength ratio may decrease due to the relatively higher strength obtained in dry specimens with respect to the conditioned ones. Indirect tensile strength ratios of asphalt paving specimens were found to be less than the Marshall Stability ratios.