HIGH-PERFORMANCE CONCRETE USING NEVADA AGGREGATES

The performance of concrete bridge decks depends on basic materials as well as external factors such as exposure conditions. The main objective of this research project is to develop concrete performance specifications for Nevada and determine measures which might be used to make concrete which passes those requirements. In order to do this, a series of concrete mix designs were developed and evaluated for their suitability to be used in Northern Nevada bridge decks and other structures exposed to harsh environments. In this research program, a total of 37 mix designs were completed using various combinations of three coarse aggregate sources, two Type I/II cement sources, two Class F fly ash sources, and four rates of cement replacement with fly ash. Testing of trial batches made from these materials yields data which shows how different materials and combinations of materials affect the final performance of the concrete. Laboratory testing based on tests suggested by the Federal Highway Administration's High-Performance Concrete Committee was used to evaluate the performance of each trial batch. The test program consists of chloride ion penetration, scaling resistance, shrinkage, compressive strength, modulus of elasticity, alkali-silica reactivity, and freeze/thaw durability. The results of trial batch testing show that different raw materials investigated have a significant impact on long-term performance and durability. In order to optimize concrete for the different effects of the raw materials and their proportions, the Nevada Department of Transportation (NDOT) should adopt a performance based specification system for concrete. As a part of this study, a proposed performance based specification system has been developed for the NDOT.