STRUCTURAL DISTRESS MECHANISMS IN CONTINUOUSLY REINFORCED CONCRETE PAVEMENT

Abstract

A study of distress types and mechanisms in continuously reinforced concrete pavement in Illinois is reported. The major purpose of the study was to determine types and amounts of distress so that improved maintenance and design procedures could be developed. The approximately 1979 km (1230 miles) of Interstate highway surveyed consisted of 18- to 25-cm (7- to 10-in) slabs over granular and stabilized subbases. Edge punchouts, steel ruptures, D-cracking, blowups, joint failures, lug rotation, longitudinal cracking, construction-related distress, pumping, and shoulder deterioration were found. Since the edge punchout is the major structural distress, its mechanism was studied in depth. Heavy truck loads, excess free moisture, deicing salts, construction practice, and poor aggregate quality in the slab are the major causes of distress. Slab thickness and foundation support have a very significant effect on the development of structural distress. D-cracking is causing severe deterioration on several projects. Overall, the performance of the thicker (23- to 25-cm (9- to 10-in)) slabs has been excellent under heavy truck traffic, but a number of thinner (18- to 20-cm (7- 10 8-in)) sections have performed poorly and are showing an accelerated rate of distress development over time. The amount of distress that is expected to occur in the future indicates a need for more efficient and durable ways of maintaining continuously reinforced concrete pavement and for revised design procedures. (Author)