Contraction and expansion of partially saturated hot mix asphalt samples exposed to freeze–thaw cycles

This paper analyses the physical impacts over hot mix asphalt subjected to freeze–thaw (FT) cycles (−18°C to +10°C) under dry and partially saturated conditions, with water or brine at different salt concentrations. Specifically, axial strain and temperatures at surface and in the heart of samples are measured during FT cycles. These measurements allow the quantification of the: (i) linear coefficient of thermal expansion (LCTE), (ii) dilation generated by formation of ice, (iii) contraction by melting of ice and (iv) freezing points variation with the degree of saturation and content of salt in brine. Under FT cycles, elongation, dilation and contraction generated by formation and melting of ice are much more significant for sample partially saturated with water (PSW). In addition, between +10°C and +23°C, LCTE value of samples PSW or brine is higher than that of sample in the dry state.