Abstract:
Skid resistance is required to prevent vehicle wheels from slipping on a
road surface. The skid resistance is influenced by surface texture of the road, which
is a function of aggregate properties and grading characteristics. This study aimed
to examine the effect of using artificial aggregates on the texture depth and the skid
resistance of two asphalt concrete surface course (ACSC) mixtures (dense and open
graded). The artificial aggregate, whichwas made from amixture of a locally sourced
fly ash geopolymer paste and an alkaline activator, was used to partially substituting
the coarse aggregate in these ACSC mixtures. ACSC slab samples, without and with
25% artificial aggregate, were produced in laboratory. The texture depth and skid
resistance characteristics were subsequently determined. This study found that the
differences in texture depth and skid resistance of the two ACSC mixtures were
contributed by the difference in gradation of the mixtures and the properties of
the coarse aggregate in the mixtures. The ACSC mixture containing 100% natural
coarse aggregate (crushed stone) has a deeper and rougher texture depth than those
containing 25% rounded artificial aggregate. Post-wheel track loading, the texture
depth and skid resistance of open graded ACSC were found to be higher than those of
dense graded ACSC. These trends were consistent regardless the type of aggregates
used in these ACSC samples. Overall, all tested samples showed skid resistance
values meeting the requirements for heavily trafficked roads in urban areas where
the traffic speed does not exceed 95 km/h.
