Pacific Power are conducting a major three-year research and development project to examine the possible use of flyash (a waste product from conventional coal-fired power generation) as a pavement material. Emphasis in the project is being placed on `pavement performance' studies. A major component of the project was a trial using the Accelerated Loading Facility (ALF). A total of 17 experiments was carried out on a range of cement-stabilised flyash (CSF) pavements. The distress mechanisms observed under accelerated loading were different for cement-stabilised flyash base and subbase pavements. In the case of the cement-stabilised flyash base pavements, the mechanism was fatigue followed by the mechanism was fatigue followed by crushing of the material. Where cement-stabilised flyash was used as a subbase under a granular basecourse, the pavements rutted after a relatively low number of loading cycles, with rutting of the granular base being the principal distress mechanism. The performance of the cement-stabilised flyash subbases under ALF loading was much worse than expected, given the performance of the CSF bases under ALF loading and the performance to date of other in-service pavements. However, the performance of the sections under ALF loading was not considered to be representative of the performance of pavements with cement-stabilised flyash subbases in practice. (A)
Abstract