Application of Different Testing Methods for Evaluating Effects of Hydrated Lime in Bituminous Mixes

Hydrated lime has been known to be one of the most effective and durable additives in increasing moisture resistance of asphalt mixes. Indirect Tensile Strength (ITS) test is probably the most widely used testing method for evaluating moisture resistance of bituminous mixes. However, this determines resistance of mixes under certain testing conditions that may not be similar to field conditions. In this research, in addition to ITS, two other tests that are normally used for other testing purposes, have been adopted. These were Marshall and Wheel Tracking (WT) tests which are commonly used for mixing design and determination of deformation resistance of mixes respectively. Asphalt Concrete (AC) mix samples, containing various amounts of hydrated lime (ranging from 1 to 2%), were prepared and were compacted in both cylindrical and slab molds. The former samples were used for Marshall and ITS testing purposes and the latter samples were used for WT testing. The above tests were carried out, both at dry and wet conditions and at two different temperatures with the aim of evaluating moisture resistance and temperature susceptibility of mixes. The results indicated that the above testing methods are appropriate for evaluating moisture resistance of AC mixes.