CONCRETE PAVEMENT REHABILITATION AND OVERLAY: ONTARIO'S EXPERIENCE

Currently, highway authorities are faced with the challenge of rehabilitating portland cement concrete (PCC) pavements on high-volume freeways. In 1989, the Ministry of Transportation of Ontario (MTO) initiated a demonstration contract to rehabilitate one such freeway using various PCC pavement repair techniques in one direction and an unbounded PCC overlay in the opposing direction. The site used to demonstrate these procedures is classed as a four-lane divided arterial with 30,000 average annual daily traffic, 10% classified as commercial. The existing pavement consisted of 230-mm mesh-reinforced dowelled PCC with 21.3-m joint spacing constructed in 1963. The rehabilitation techniques used included full-depth repair, partial-depth repair, diamond grinding, and joint sealant replacement on the northbound lanes that had experienced moderate deterioration. The southbound lanes received a 180-mm-thick plain jointed unbonded PCC overlay to address the severe D cracking and spalling of all joints and cracks. Design and construction details and the performance of the pavement, before and after rehabilitation, are discussed in terms of load transfer efficiencies and pavement edge deflections based on falling weight deflectometer testing; roughness using the profilograph, the portable universal roughness device, and the automatic road analyzer; skid resistance using the ASTM brake force trailer; pavement condition ratings; and a crack survey. Observations of noise levels, traffic volumes, and surface texture are also presented.