Many of Ontario's freeway surfaces are showing signs of premature surface deterioration in the form of map cracking, ravelling, and coarse aggregate loss associated with the use of 100% steel slag coarse and fine aggregates in the hot mix wearing course. The majority of these freeways will require rehabilitation within the next few years. In 1991 the Ministry undertook a demonstration project to determine if micro-surfacing would extend the life of freeways exhibiting this type of premature surface deterioration. Highway 403 exhibited severe map (block) cracking throughout the entire length of the project and slight to moderate ravelling in some areas. Two contractors, using two different micro-surfacing systems, placed a 3 km four-lane trial section on the Highway 403 demonstration project. This paper describes the design, testing procedures, material characteristics, construction, and short-term performance of the micro-surfacing systems placed. It also discusses the viability of micro-surfacing as a surficial rehabilitation treatment under freeway conditions. (A)
Samenvatting