Joint Sawing Practices and Effects on Durability

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. The problem is wide-spread and severe enough that a Federal Highway Administration (FHWA) pooled-fund project was initiated to investigate the cause. Six states participated and the project focused on material properties which may cause the premature deterioration from concentrated deicer salts. The concrete industry has also performed large amounts of research related to premature distresses. While specifications and testing help to identify d-cracking 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. Dr. John Kevern of the University of Missouri-Kansas City, co-principal investigator on this project, is currently finishing a project for the Kansas Department of Transportation (DOT) titled “Investigation into the Effect of Sawing Method on Concrete Joint Deterioration,” where the microstructure and durability of field-placed sections were investigated. This research plan has been designed to refine the components of the Kansas DOT study that worked well and also to incorporate additional sawing variables which may influence durability. This lab study will involve testing field-produced concrete which includes the expected primary and potential secondary variables contributing to premature joint deterioration as influenced by the method of sawing.