Insitu stabilisation is a proven technique for both new construction and rehabilitation of existing roads. Performance studies of existing roads in excess of 20 years have shown that road owners achieve excellent value-for-money results from this pavement technique. A lack of design details, poor specification clauses, and poor construction practices by contractors with little knowledge of the process, quality control and materials may cause early distress of roads. Also, one of the problems faced by contractors during tendering is the variation of specifications.
For example, in insitu stabilisation specifications are likely to change from one region to another region or State. It is frustrating to find that one council would specify binder content by volume and another by weight. This all leads to confusion and may lead to insufficient binder content in the pavement material.
In attempt to minimise problems with road stabilisation AustStab has sought to produce a model specification for use by Councils and Shires, State Road Authorities and major contractors involved in DCM style contracts. A working group in AustStab was formed to prepare this model specification aimed at specifying stabilisation of local and main roads for both urban and rural areas. It also gave consideration to practices adopted in all regions of Australia, such that specifiers would not require tedious amendments.
In the specification there are options to include and deleted paragraphs and clauses based on the contractual requirements and practices by Councils, Shires and SRAs in Australia. At the end of the specification is a schedule of rates that is required to be completed by the contractor in their submission to the tender documents. These model specifications are only available for free for Australian engineers and members of AustStab.