Over the past few years, the Ontario Ministry of Transportation (MTO) has gradually increased their usage of Superpave asphalt mixes in provincial paving contracts. It is anticipated that a complete transition to Superpave will occur at the provincial level within the next few years through the efforts of the multi-stakeholder Ontario Superpave Implementation Committee. In order to assess municipal mixes under Superpave criteria, the City of Ottawa retained numerous asphalt mix samples during normal quality assurance operations during the 2002 paving season. These mixes were compacted to 100-gyrations in the gyratory compactor to observe the gyration level at which the 4% air void criterion (Ndes) was met. Significant adjustments to mixes currently used in the City of Ottawa will be required to meet Superpave specifications including (but not limited to) a reduction in the amount of natural sand, a slight reduction in asphalt cement content and gradation adjustment to fall below the restricted zone. Both internally and through the Ontario Superpave Implementation Committee, the City of Ottawa will continue to work toward implementation of Superpave and provide other municipalities with technical expertise during the transition.
Samenvatting