Research on hot rolled sheet overlays in Indonesia.
A comprehensive research programme has been established to develop performance prediction models for the alternative structural road surfacings in Indonesia and to improve specifications and thickness design. For this purpose detailed observations have commenced on 25 monitoring sections selected from a 360 km sample of the road network which was subject to a
general condition survey. The road links and sections cover a wide range of design parameters and performance.
This report describes the design and implementation of the research on existing bituminous overlays and contains some early results and details of the pavement structures and overlay mixes.
In general, the performance of the mixes made to a hot rolled sheet specification is very variable. Although mean values for the rate of rutting and crack development can be low 90 percentile values are high with critical conditions being reached within a few years. Correspondingly, the properties of the mixes manufactured to a common specification are variable, ranging from gap-graded to continuously-graded and covering a wide range of bitumen content .and other properties.
Given the degree of variability, it is not possible to make conclusive recommendations at this stage. Further observation of the monitoring sections and at a network level is required.
Fourth Annual Conference on Road Engineering, Jakarta, 19-21 November 1990. TRL - Crowthorne, UK. pp. 31