Use of Bitumen Stabilised Limestone in Western Australian Road Pavements

Bitumen emulsion stabilisation of locally available Tamala Limestone was widely used by State and Local Governments from the mid-1960s through the late-1990s, however its use has declined in recent years. This paper aims to substantiate its benefits as a viable alternative material for use on heavily trafficked roads. The benefits provided through stabilisation of crushed limestone with bitumen emulsion include improved workability, reduced ravelling under construction traffic, lower moisture susceptibility and enhanced mechanical properties. Case studies are presented that show that satisfactory performance has been observed where Bitumen Stabilised Limestone (BSL) is used as a basecourse under heavily trafficked roads. The paper provides a construction methodology and discusses barriers and future opportunities. Two structural design approaches are presented for the use of BSL under sprayed seals and thin asphalt surfacings.