National Concrete Pavement Technology Center

Project description

Joint deterioration has become a renewed concern for concrete pavements in Northern climates. Recently, a large number of relatively young pavements (less than 20 years) have experienced premature joint deterioration requiring disproportionately high amounts of maintenance. While specifications and testing help to identify dcracking aggregates, optimize mixtures for low shrinkage and permeability, utilize advanced air testing techniques, and help determine potential deicer issues; the current joint deterioration problem spans many states and concrete mixtures and has the potential, if left unchecked, to seriously damage the reputation of concrete pavements as durable, low maintenance options. This research report presents findings from joint durability studies conducted on test specimens extracted from two research test sections specifically built with southern limestone and northern igneous gravel as the predominant coarse aggregates. Transverse saw cuts were made with conventional and early entry saws using a variety of blade types and post-construction timing intervals. Sections sawn early in the timing window exhibited physical damage to the aggregate and concrete. Sections sawn with old/worn saw blades were more absorptive to water and exhibited more variability. Silane treatment of the joints provided significant reduction in water absorption. The concrete mixtures were freeze-thaw durable to 300 cycles and had acceptable performance to 600 cycles. Surface deicer scaling was not influenced by sawing factors. The application of silane did not reduce chloride penetration for the limestone mixture but did reduce penetration by 50% for the gravel mixture.