An improved approach for characterisation and design of chemically stabilised pavement bases

A. Sounthararajah and J.Kodikara

This paper aims to develop measures to minimise the initial fatigue damage of prematurely opened cement treated bases (CTBs) due to repeated application of heavy traffic loads. A laboratory investigation was undertaken to characterize the early-age flexural fatigue performance of cement-stabilised pavement materials (CSPMs) under repetitive loading. The flexural fatigue test results evinced the existence of an endurance limit in CSPMs, even at seven days curing age. A stress- based flexural fatigue performance model was developed for predicting the early-age flexural fatigue performance of CSPMs in service. In parallel with the laboratory tests, mechanistic analyses were performed using the CIRCLY program to assess the early-age response of CTBs to heavy traffic loading. The computed critical pavement responses and the flexural fatigue performance model developed in this study were then used to estimate the early-age fatigue damage of CTBs in terms of seven days curing. It was found that the asphalt cover over CTB required to prevent the occurrence of initial fatigue damage to CTB decreases with increasing modulus and thickness of CTB and subgrade strength.