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.

The current list of model specifications are noted below and you can download the commentary and specification in Acrobat format for free.

Model Specification 1 Insitu Stabilisation of Local Government Roads with Cementitious Binders including Lime (Version D – Minor changes)

Model Specification 2 Insitu Stabilisation of Local Government Roads with Bituminous Binders (Version C – Minor changes)

Model Specification 3 Insitu Stabilisation of Main Roads with Bituminous Binders (Version B)

Model Specification 4 Plant-mix Stabilisation of Main Roads with Bituminous Binders (Version A)

Model Specification 5 Insitu Stabilisation of subgrades and pavement materials using lime for Local Government Roads (Version B)

Model Specification 6 Insitu stabilisation of subgrade materials using lime for main roads (Version A)

Model Specification 7 Insitu Granular Stabilisation of Local Government Roads (Version A)

Model Specification 8 Model Specification for Supply of Limestone for Acid Sulphate Sites (Version A)

Model Specification 10A2Model Specification for insitu stabilisation of local government roads using insoluble dry powdered polymers (Version A2)