Abstract:
Friction capacity between the tire-pavement interface, facilitates sufficient
braking force ensuring road user safety. Inadequate skid resistance has been identified
as the prominent pavement-related cause of highway crashes. Availability of friction
at the wearing course is governed by pavement, vehicle and tire/driver condition
parameters combined with environmental parameters, of which pavement-related
characteristics concern a greater proportion. Crucial pavement-related characteristics
include mineralogical and textural properties of road surfacing aggregates, where the
polishing behaviour of coarse aggregates exhibits significant influence in the establishment
of skid resistance of asphalt concrete pavings. Thus, many research have
been conducted to determine the suitability of aggregates, in terms of resistance to
polishing under trafficking. In the national context, broader attention is being developed
towards road safety as one of the critical performance parameters due to the
integration of an expressway system with the prevailing road network. However,
the amount of such extensive study into pavement friction and properties of locally
available aggregates, is scarce. No guidelines considering user safety have been
specified in the Standard Specifications for Construction and Maintenance of Roads
and Bridges by the Institute for Construction Training and Development, Sri Lanka.
Therefore, initiatives to incorporate skid resistance in the national practice of aggregate
selection for pavement construction, are indispensable. Hence, this study aims
to establish the friction characteristics of Sri Lankan natural roadstones, through
the Polish Stone Value Test involving the Accelerated Polishing Machine and the
British Pendulum Tester, and to evaluate the observed polishing patterns through a
petrographic analysis and microscopic investigation.
