Significance of Pavement Design and Materials in D-Cracking. Final Report

摘要

A two-phase investigation was carried out to determine the efficacy of reducingthe maximum size of coarse aggregate to minimize freeze-thaw damage and the development of D-cracking in highway pavements. This included evaluating factors not amendable to laboratory conditions. One phase consisted of repeat pavement surveys of already existing pavements to determine whether reducing maximum particle sizes of coarse aggregate alleviated D-cracking. Results are summarized in an interim report for the project, dated December 1986. The other, primary, phase was the construction and monitoring of a test pavement on SR2 near Vermilion, Ohio, which incorporated design as well as materials variables with respect to D-cracking (and other performance characteristics). Results after 16 years of service (1975 through 1990) indicate that reducing the maximum size of coarse aggregate can alleviate D-cracking, and that, once initiated as seen at the wearing surface, traffic loading becomes an important factor in propagating the extent and severity of deterioration. Daylighting the granular subbase (no artificial drains) greatly improved the rideability of the pavement, while other factors, such as source of cement, joint sealants, subbase vapor barriers, and longitudinal drains were of minor, if any, significance. Other effects on performance also were noted.