Resilient modulus of Malaysian base and subbase pavement materials

Abstract

Pavement design approach is shifting towards analytical or mechanistic-based procedures. Resilient modulus is a fundamental parameter used in the procedure and a study was carried out to characterise the parameter for base and subbase pavement materials used in Malaysia according to the Public Works Department of Malaysia’s (PWD) Specification for Road Works (JKR/SPJ/1988). This paper details the study and describes the materials tested, the methodology used and the results obtained from the study. In this study, base (Type II) and subbase (Type E) specimens of 100 mm diameter x 200 mm height were tested using the repeated load triaxial test in accordance with AASHTO T307-99. In addition, the test was carried out at different gradation compositions (but within the required gradation envelope) and moisture contents to study their effects on the resilient modulus value. From the test, the k-θ model was used to characterise the base and subbase materials. Finally, recommendations on a set of resilient modulus values for Malaysian base and subbase materials to be used for mechanistic design of flexible pavements were made, taking into account of the Malaysian environment.