Published: 22 March 2019

Legislative Council Wednesday 20 March, 2019


My question follows two previous questions regarding the deterioration and condition of a recently upgraded section of the Murchison Highway, which I noticed when driving down there recently has again been resealed. The Leader indicated that the cause of the rapid deterioration of the surface had not been determined and was being actively investigated by the department and the construction contractor.

The Leader also stated initial indications are that the deterioration could be due to either material quality or workmanship issues by the contractor. These questions were first raised in October 2018. I now ask - 

(1) Has the cause now been identified? 

(2) (a) If so, what is the cause? 

(b) If not, when is this information expected to be provided? 

(3) Has the departmental review of its construction specifications and quality assurance processes being completed? 

(a) If so, what where the findings and the outcomes of the review? 

(b) If not, what is the expected date of finalisation, and why is this review taking such an extended period to complete?


Mr President, I thank the member for Murchison for her question. 

(1) Yes, the cause of the seal failures has been identified.

(2) The road surface failures occurred because of an inadequate primer seal. This section of the Murchison Highway, which is between Pieman Road and Farm Creek Bridge and 3.5 kilometres north of Pieman Road, received its first seal - primer seal - approximately one year ago. This primer seal is intended to only be an interim measure until the final seal can be applied. This is the normal sealing practice used by the Department of State Growth to ensure proper adhesion of the final seal. As the application of the primer seal was not suitable for this specific site's conditions, the road surface failures have been fixed by the contractor, VEC Civil Engineering Pty Ltd, at its expense.

(3) (a) and (b)

The construction specifications have been reviewed, including external peer review, to understand the cause of the recent failures, and no fault has been found with those specifications. 

In relation to the Murchison Highway, the review considered whether its construction methodology complied with the specifications. In some aspects the seal design was not consistent with the relevant Austroads 

Guides and the local conditions expected. 

To address these issues, the department has applied additional contractual provisions to ensure the contractor is fully responsible for the work and that local conditions are adequately considered at the time of the works. Future contracts will make it the responsibility of the contractor to complete both initial and final seals rather than the department engaging a separate contractor for the final sealing, as has been past practice. 

Future works will be planned so that a final seal will be placed within the one construction season rather than the previous practice of placing an initial seal during one season and placing a subsequent seal in the following season. 


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