The paper describes a risk assessment model for the performance risks associated with unbound granular materials in Queensland pavements. Fault tree analysis was used to model the interactions between pavement performance variables that contribute to failure modes for unbound granular materials. The model provides risk ratings for each failure mode that are then aggregated into an overall risk ranking. The model considers failure modes for unbound granular paving materials, including rutting in the base layer, potholes due to material deficiencies, fatigue and longitudinal cracking, and loss of skid resistance due to sealing aggregate punching into the base. Performance variables contributing to these failure modes include traffic, rainfall, material properties, cross-section, construction and maintenance. The model assigns likelihood ratings to each performance variable, and consequence ratings to each failure mode. Comparison with case studies and field investigations has shown good agreement between risk rankings and actual performance. The model allows comparison of project scenarios in terms of material performance risk. (a) For the covering entry of this conference, please see ITRD abstract no. 0612AR242E.
Samenvatting