Sealing works performance study

Abstract

Bitumen sprayed seals are an effective and economical road surfacing technique utilised widely across the world. The premature failure of road surfacing can be detrimental to road user safety with some surfacing failures causing a reduction in skid resistance, large profile irregularity and loose stone on the road surface. This research project was commissioned by the Department of Transport and Main Roads, Queensland. The objective of this dissertation is to develop and implement an evaluation system to ensure effective investigation, design, application and evaluation of bitumen seals. The objectives are focused on roads in the Far North region of Queensland, Australia. Premature flushing of sprayed seals has been identified as the failure mode of greatest consequence. Flushing causes a reduction in skid resistance and the increased propensity for road crashes. The New Zealand TNZ P17 Performance specification predicts the premature flushing based on texture depth measurements one (1) year after the seal is constructed. The specification has been successfully implemented in New Zealand and America. The TNZ P17 specification has been adapted to the Far North region road network. However, due to inaccurate data used to modify the specification models the predictions may not reflect the actual seal behaviour in the Far North region. Further data collection and refinement is required. This dissertation details the process for adapting the TNZ P17 performance specification to any region in the world, provided that accurate seal data exists