Durability design of high performance concrete and its application in bridge decks

In the present study, the investigation of high-performance concrete included optimizing concrete mixtures and identifying their performance characteristics related to durability for the purpose of using these characteristics in performance related specifications. The research effort described in this thesis was divided in two parts. PART ONE of the study focuses on development of concrete mixtures optimized with respect to selected performance characteristics. During this part, four optimum concrete mixtures are identified from 45 mixtures in terms of four parameters: namely, compressive strength, elastic modulus, rapid chloride penetration, and chloride conductivity using a statistical design procedure. A total of twenty-seven statistical models were developed for the four performance characteristics selected in the study. Based on the models developed, 81 contour plots were generated. Based on the overlaid contour plots and the threshold values chosen for performance characteristics of concrete, a total of ten optimum concrete mixtures including plain, binary and ternary mixtures (containing fly ash, silica fume or slag) were identified. In PART TWO of this study, the previously identified ten concrete mixtures were further evaluated with respect to mechanical properties and durability characteristics. Several different tests, which were related to the evaluation of the resistance of concrete to chloride permeability, were used: rapid chloride ion permeability test, chloride conductivity test, test for measurement of electrical current under a DC electrical field, ponding test for the determination of the resistance of concrete to chloride penetration, and rapid test for the determination of diffusion coefficient from chloride migration. Tests related to the resistance of concrete to freezing and thawing, and scaling were investigated. Other tests such as, the determination of drying shrinkage, and test for curing effects on the properties of high performance concrete were also evaluated in this research. Special emphasis was placed on determining and quantifying these parameters that could control the ingress of chloride ions. Based on the results achieved during this research, statistical models have been developed that allow for prediction of mechanical and durability-related parameters related to the mixture composition. The parameters that can be predicted include compressive strength, rapid chloride permeability (RCP) values, and chloride diffusion coefficient.