Date of Graduation

8-2024

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor/Mentor

Murray, Cameron D.

Committee Member

Hale, W. Micah

Second Committee Member

Heymsfield, Ernest

Keywords

Alternative Cements; BCSA Cement; Concrete; Setting Time; Size Effects

Abstract

Belitic calcium sulfoaluminate cement (BCSA) is an alternative to portland cement which offers numerous benefits due to its rapid-setting behavior and sustainability properties. BCSA cement concrete has many potential applications, particularly for structural and transportation infrastructure repair. Due to the rapid-setting properties of BCSA cement, a comprehensive understanding of the setting process is critical for efficient and effective use of this material. The primary objective of this research was to determine the effects of mixture size on the setting time and temperature behavior of BCSA cement concrete, and to investigate the relationship between initial set time and workability. Using a constant mix design, several BCSA cement concrete mixtures were created to test both batch and placement size effects. Temperature and ultrasonic pulse velocity (UPV) testing were performed to estimate the initial set time for all mixtures. A further set of mixes was performed to evaluate the relationship between initial set time and workability for BCSA cement concrete. Mortar penetration, temperature testing, and UPV were all monitored for each mix, while a workability relationship was estimated using the slump test. Overall, some changes in initial set were found for BCSA cement concrete as batch sizes were increased, but temperature and citric acid retarder dosage likely played a more significant role in the changes to initial set time. Likewise, minimal differences were seen in initial set time for mixes of varying placement size. Furthermore, the study found that the initial set time determined using mortar penetration gives a good approximation for the actual working time of BCSA cement concrete. An ultrasonic pulse velocity of 3500 m/s was also found to be a fairly accurate approximation for both penetrometer initial set, as well as working time for BCSA cement concrete mixtures. Overall, common estimates for initial set generally approximate the workability of BCSA cement concrete mixtures, while UPV has the potential to be used as a setting time test.

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