Semester

Summer

Date of Graduation

2010

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Roger H. L. Chen.

Abstract

This study focused on the construction and placement issues that are common among the production and utilization of self-consolidating concrete (SCC). Six distinct areas were looked at. Robustness and loss of passing ability were related to the change in water and high range water content. Mixes were batched and altered in such a way to determine the point when lack of robustness becomes unacceptable. The compaction, by vibration, of an SCC mix is not normally necessary, however may be needed under certain scenarios. A standard test for determining the static segregation resistance of SCC was altered to determine the effects of vibration duration. A foam layer was sometimes observed on the top of freshly cast SCC. It was found that this layer could be from certain material constituents, high fineness modulus of sand, High Range Water Reducer, or mix instabilities which are detrimental. A guideline for conducting trial batches in the laboratory was established. Field trips to ready-mix and precast plants producing SCC were conducted. SCC mixes can be replicated, in a production environment, although environmental and human factors can cause variability in the mix. SCC is more fluid than that of traditional vibrated concrete; it is believed to have a higher influence on the developed formwork pressure. Short and tall columns were erected and traditional vibrated concrete (TVC) as well as SCC mixes were cast in them. The lateral formwork pressure was recorded using sensors.;The results from this study show that a robust SCC mix can tolerate up to about a five percent increase in water content. A robust SCC mix can also be vibrated in short duration if need be. The generation of air and its migration of air with a fluid body of SCC were explored in order to determine how properties of the mix such as fineness modulus of the sand, mix instabilities, and HRWR (High Range Water Reducer) could cause this phenomenon. Guidelines for making and reproducing small batches of SCC in the laboratory were made and took into account the aggregates, chemical admixtures, the mixer, and batch sequence. The formwork pressures measured in short columns (47 in. head height) reached full hydrostatic pressure using TVC and SCC. The tall TVC and SCC columns (105 in. head height) tested did not reach hydrostatic pressure, but the pressure measured in the tall TVC column was significantly lower.

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