DURABILITY OF PARKING STRUCTURES: ANALYSIS OF FIELD SURVEY. CONCRETE DURABILITY. KATHERINE AND BRYANT MATHER INTERNATIONAL CONFERENCE, HELD AT ATLANTA, GEORGIA, USA, 27 APRIL-MAY 1987

A total of 215 garages in Toronto, Ottawa and Montreal, Canada, have been surveyed to various extents by assessing delamination, half-cell potential, depth of cover, and component condition. In addition, tests were carried out on cores, in which chloride content, compressive strength, and chloride permeability were determined and the air void system was analysed. The evidence indicates that durable garages can be built, and that poor performance must be attributed to design and construction practices whose effectiveness falls short of that required by the environment. It follows that almost all previously built garages will eventually require repair unless upgraded before the chloride concentration of the concrete reaches a critical level. Repair by the "patch and waterproof" method was found to decrease the rate of corrosion of deteriorated garages by approximately 70 percent. Detrimental effects following installation of a waterproofing membrane over concrete with elevated chloride concentration were not observed. No relation was detected between extent of delamination and crack density or compressive strength. Half-cell potential did not prove more sensitive than the chain-drag test in detecting delamination. (Author/TRRL)