Reduction of Minimum Required Weight of Cementitious Materials in WisDOT Concrete Mixes

摘要

This project was designed to explore the feasibility of lowering the cementitious materials content (CMC) used in Wisconsin concrete pavement construction. The cementitious materials studied included portland cement, fly ash, and ground granulated blast furnace slag. For the first phase, mixtures were prepared using the current WisDOT aggregate grading specification. For the second phase, mixtures were prepared using an optimized (e.g. Shilstone) gradation. A variety of tests for fresh and hardened concrete were conducted to determine the viability of low CMC mixtures for use in concrete pavement. The research resulted in several successful low CMC concrete mixtures in terms of workability, strength, and durability. Many unsuccessful low CMC concrete mixtures were also produced. The analysis of the data suggests a practical minimum CMC of 5.0 sacks/yd(sup 3) for concrete. However, successful mixtures containing fly ash were achieved at the CMC levels of 4.0 sacks/yd(sup 3) and 4.5 sacks/yd(sup 3). The same minimum CMC limits were established in both the first and second phases of the research, regardless of the change in aggregate gradation.