A major cause of concrete deterioration on bridge structures is the corrosion of the embedded steel reinforcement. In response to the continued problem of corrosion, FHWA initiated this research aimed at (1) quantifying the corrosive conditions fostering concrete bridge deterioration and (2) identifying concrete materials which consistently provide superior performance when used in bridge applications. The experimental phase of this research project was divided into three tasks: Corrosive Environments Studies, Concrete Chemical and Physical Properties, and Long-Term Corrosion Performance. This paper reviews the results oi the study of the effects on corrosion of chemical components of concrete. Experiments were performed to identify the chemical components of concretes that affect corrosion induced deterioration of concrete structures. The dependent variables of interest in examining corrosion induced deterioration of concrete are corrosion rate, corrosion potential, chloride permeability, electrical resistivity, and compressive strengfh. This paper focuses on the corrosion properties. The independent concrete component variables examined included: water-cement ratio, air content, coarse aggregate type, fine aggregate type, mineral admixture, and cement type. Because of the large number of independent variables and the number of levels of interest for the variables, an optimized experimental design was developed to permit the estimate of the main-effect terms for each independsnt variable. Models were developed to predict the effect of the independent variables on corrosion rate and corrosion potential in each of two environments.
Keyword: concrete, mortars, reinforcing steel, corrosion rate, corrosion potential, model predictions, chloride, temperature, relative humidity, water-cement ratio, air content, aggregate, mineral admixture, cement.