A full-scale road experiment on a heavily-trafficked route in Kuala Lumpur is described. The experiment was devised to investigate the relative structural value of dense bituminous-bound bases and crushed-stone bases in a tropical environment. Short sections of road were constructed with different base thicknesses of both materials. A common surfacing of two course bitumen macadam was laid on all the sections. The performance of the experimental sections over four years has been assessed. Although firm conclusions cannot be drawn on the long-term performance of the pavements on the basis of only four years' trafficking, the changes in pavement condition that have occurred indicate that the bitumen-bound bases are equivalent to crushed-stone bases 1.1/3 times as thick. The early evidence indicates that the recommendations that are used in Britain for the design of flexible pavements for heavily-trafficked roads are also valid in the Malaysian environment. Tentative deflection criteria for estimating the residual life of macadam surfacings in the tropics are given, and the effect on pavement deflection of adding an overlay is reported. (Author/publisher)
Abstract