National Concrete Pavement Technology Center

Project description

Although classification tables based on susceptibility to chloride ion permeability are recommended in AASHTO T 358, the classification levels with respect to durability parameters may or may not be adequate. Of interest for concrete pavement performance, this study verifies the recommended classification levels against standard durability testing such as corrosion, salt scaling, and freeze-thaw. The researchers conducted corrosion, salt scaling, and freeze-thaw durability tests in parallel with electrical surface resistivity testing to compare performance classifications for each method. Twenty-four mixture designs were evaluated. The designs vary in water-to-cementitious material ratio (0.4, 0.45, and 0.5 w/cm ratio), supplementary cementitious material type (100% ordinary Portland cement, 20% Class C fly ash, 40% Grade 100 slag cement, and 8% silica fume replacements), and air content (air entrained and non-air entrained). The results of the experimental study indicate that there is no clear relationship between concrete electrical conductivity and durability performance based on standard methods of testing. It may not be appropriate for the determination of durability performance of a concrete mixture for concrete pavement construction. However, the test method does present advantages, as mixtures of similar composition and design can yield the same results over time under standardized curing. Here, resistivity-time curves could be a useful tool as part of a quality control and quality assurance program to ensure consistency in concrete delivery during construction.