Study of D-Cracking in Portland Cement Concrete Pavements. Volume 2. Laboratory Phase

摘要

Thirty locations were chosen from the pavements surveyed for the Field Phase Report. Cores were taken and tested for compressive and tensile strength, core density, and freeze-thaw durability. Also, laboratory concretes with variables of aggregate type and size, and water to cement ratio were tested for freeze-thaw durability by ASTM C-666 method A. Laboratory water penetration tests on newer pavement concretes, a dried aggregate field test section, and a condition comparison of adjacent pavement with and without traffic were made. Some observations and conclusions made: D-crack deterioration did not relate to concrete density or strength; air-entrained field concretes were the most freeze-thaw durable; in our tests smaller aggregate size did not relate to better freeze-thaw durability; heat drying the aggregate was not beneficial; pavement cores showed high water penetration; traffic promotes ravelling of D-crack surfaces but is not necessary for its occurrence.