Rural Local Authorities in New Zealand desire to see their sealed network extended but are unable to meet economic criteria. In the mid-1980s some roading authorities without appropriate supplies of good roading aggregates saw the benefit of treating unsealed pavements with lime. As a consequence the practice became widespread but Transit NZ only granted financial assistance on the proviso the road was not submitted for seal extension within a five year period. An initial trial was very successful for the Hastings District Council so it embarked on an ongoing program of lime stabilisation. Subsequent problems were encountered later and research was initiated to determine whether the process was process was appropriate or there were alternatives . Lime stabilisation treatment of an unsealed road without a demanding horizontal alignment or subject to long dry periods is appropriate. The criteria imposed by Transit NZ prohibiting sealing of the road for a period of five years after the work appear to be inappropriate in some situations due to very high maintenance costs. (A)
Abstract