Asphalt Mixture Sensitivity to Water and Frost

Abstract

This paper presents recent study on the moisture susceptibility of asphalt mixtures under various water and frost conditioning. Moisture susceptibility of asphalt mixture is a very important property influencing significantly pavement durability. In particular, asphalt layers are subjected to a deterioration factor which is traffic independent—water and frost/thaw cycles. It is a common practice that during the mix design process qualitative experiments are conducted in order to assess the moisture resistance of trial mixes. Therefore there is a need for a suitable, validated and generally accepted method. This paper presents the results of the extensive research study conducted recently in Poland to compare several different testing protocols and associated requirements for the moisture sensitivity. Different aspects of the asphalt mixtures were investigated, in particular aggregate type, anti-stripping agent and bitumen type. Specimens for the moisture susceptibility were conditioned using four methods including an original method comprising the frost/thaw cycles as well as AASHTO T-283 protocol. In addition to the standard evaluation of the indirect tensile strength, there were several performance based tests conducted in the laboratory on the specimens before and after the conditioning procedures. The analysis shown in this paper lead to the development of the alternative specifications for the moisture susceptibility in Poland.