| dc.description.abstract | Ultra-high-performance concrete (UHPC) is a relatively new material that is growing in popularity and usage over recent years. The greatly increased strength and durability of UHPC compared to conventional ACI concrete makes it an attractive material for designing stronger and more efficient structural systems. However, the high costs of specialty materials needed to make UHPC have encouraged researchers to investigate methods for optimizing UHPC mixes with a balance of cost and performance in mind. Popular means of optimization include different curing conditions, particle packing methods, and the exploration of different amounts and types of materials. Materials that are commonly used and varied between different UHPC mix designs include steel fibers, silica fume, and portland cement.
The purpose of this research project was to investigate the effects of different types of cement and their properties, particularly chemical composition and heat of hydration, on the performance of a standardized UHPC mix. The methods of investigation included compressive strength testing of cube specimens at age intervals of 1 day, 3 days, 7 days, 14 days, 28 days, and 56 days, as well as calorimetry testing during the initial 3 days of hydration. Eleven different cements from six different manufacturers were investigated in this study. The collected data indicated that Type I/II portland cements performed the best overall. Investigating the individual chemical compositions showed few trends correlating individual values with higher compressive strength, though cements with higher C3S, C3S+4.75*C3A contents, and Blaine fineness had a slight tendency to have higher compressive strength at 56 days. Investigating the area formed under the measured calorimetry curves also yielded a positive trend between larger areas and higher compressive strengths, especially for 1 and 3 day strength. | en_US |
