Mechanical Properties of High-Performance Concrete Made for Bridge Decks using West Virgina Aggregates

摘要

As a part of a research program on development and evaluations of high-performance concrete (HPC) for the state of West Virginia, in this study sixteen HPC mixtures were produced using two types of locally available 25 mm graded limestones, gravels, and one type of river sand. For each type of aggregate, four kinds of HPC were developed by using the following mineral admixtures: (1) 10% metakaolin; (2) 20% fly ash and 5% silica fume; (3) 30% slag and 5% silica fume; and (4) 15% fly ash, 25% slag and 5% silica fume. A constant water-cementitious material ratio of 0.4 and aggregate-paste volume ratio were maintained for all mixtures. In addition to basic fresh properties, compressive strengths at 1, 3, 7, 14, 28 and 90 days, 28-day modulus of elasticity (secant and dynamic) were measured. Preliminary data show that metakaolin HPC achieved the highest strengths, particularly at ages up to 28 days, followed by slag-silica fume HPC, fly ash- silica fume HPC and fly ash-slag-silica fume HPC. At 90 days both metakaolin HPC and slag-silica fume HPC achieved almost the same range of strengths. Overall, limestones performed better than gravels in terms of both strength and moduli of elasticity. Modified empirical relations between compressive strength and static modulus, and dynamic modulus and static modulus are proposed. Since the expressions are based on a large number of specimens for both limestone and gravel mixtures, including different types and dosage of mineral admixture, the results can be used for prediction of HPC of similar strength and materials.