Rutting evaluation of stone mastic asphalt for basalt and basalt–limestone aggregate combinations

The purpose of this study is to investigate the rutting of basalt and basalt–limestone aggregate combinations for coarser and finer SMA mixtures with a Laboratoire Central des Ponts et Chaussées (LCPC) wheel tracking test. The sensitivity of the LCPC wheel tracking test was also evaluated with different maximum aggregate sizes and changes in gradation. The coarse aggregate in the mixture was basalt. Four different rock combinations were designed with basalt and limestone aggregates for filler and fine fractions. In addition to the gradation evaluation, the maximum aggregate size effects were studied with four gradations. Decreasing the maximum aggregate size is at the utmost importance on rutting resistance, according to the gradation and mineralogical factors of aggregate. It is believed that limestone aggregate can be used as filler and fine fractions in SMA with basalt. This matter has great importance for shortage of basalt aggregate quarries and management difficulties for these quarries. This provides added value for Turkey’s highway investments. Rutting resistance of SMA mixture relatively decreased in the incorporation of limestone aggregate in the SMA mixture gradation as fine or filler aggregate (an average of 0.24% for SMA11 and SMA12, and 0.41% for SMA21 and SMA22). This low-level rutting difference can easily be observed with LCPC wheel tracking tests. Reliability of LCPC test was clearly demonstrated.