Cement stabilisation of road base course: A chronological development in Western Australia

The use of cement stabilisation technologies was first pioneered in Australia as early as the 1950s. However, its use did not spread to Western Australia until the 1970s when an investigation was commissioned by Main Roads Western Australia (MRWA) to assess an alternative for bitumen stabilisation of base course. Cement stabilisation was identified to be a potential option as strength parameters of cement stabilised pavements were comparable to those of bitumen stabilised pavements. This paper presents the development of cement stabilisation technology from the laboratory investigation in 1970s, through to the construction of Leach Highway Trial Pavements, followed by the extensive laboratory testing by MRWA, and finally to the construction of Reid Highway Trial Pavements. In these investigations, cement has been assessed for its use as a stabilisation agent and subsequently a modifying agent and was found to be problematic, i.e. cement stabilised pavements exhibited issues of binder permanency, fatigue and shrinkage. As an immediate reaction to the observations of these investigations, MRWA prohibits the use of any appreciation in pavement strength from cement treatment when designing pavement thicknesses as covered in the current Engineering Road Note 9 (ERN9) 2010. A review of these events leading up to the publication of ERN9 2010 is presented along with testing regimes identified to close the knowledge gap.