Laboratory investigation of the characteristics of SMA mixtures under freeze-thaw cycles

- The impaction of freeze-thaw cycles and additive type on Stone Mastic Asphalt (SMA)
- Initial porosity plays an important role in the performance of SMA under freeze-thaw cycles.
- Freeze-thaw resistance of SMA mixtures with lime was better than those with cement and without additives.
- SMA mixtures exhibit brilliant performance on the resistance to freeze-thaw damage.

In this study, the effects of freeze-thaw cycles on the characteristics of Stone Mastic Asphalt (SMA) mixtures, containing cement 30% or lime 20%, are investigated under different freeze-thaw cycles. SMA mixtures were produced in a laboratory environment. Specimens containing different additives were prepared with different air void ratios ranging from 2.5% to 6.0% based on the calculated optimum bitumen amount. The volumetric properties, Marshall Stability (MS), flow and freeze-thaw split tensile strengths were experimentally determined for each specimen at the end of the 1st, 3rd, 5th, 8th, 10th, 15th, 20th cycles. Test results indicate that initial air void ratio plays an important role in the performance of SMA under freeze-thaw cycles; freeze-thaw resistance of SMA mixtures with lime was better than those with cement. The MS values of SMA decrease between 24.4% and 56.5%, 26.5% and 45.5% and 17.9% and 14.1% for samples without additives, samples with cement, and samples with lime after 20 freeze-thaw cycles, respectively. SMA mixtures exhibit brilliant performance on the resistance to freeze-thaw damage.