Date of Graduation

5-2020

Document Type

Thesis

Degree Name

Bachelor of Science in Civil Engineering

Degree Level

Undergraduate

Department

Civil Engineering

Advisor/Mentor

Murray, Cameron

Committee Member

Coffman, Richard A.

Second Committee Member

Fernstrom, Eric

Abstract

Belitic Calcium Sulfoaluminate cement (BCSA) is an emerging technology in the concrete industry. BCSA has similar hardened properties to portland cement (PC) but can set in under 20 minutes and reach 4,000 psi in less than 2 hours. Portland cement accounts for 8% of the world’s CO2 emissions, BCSA cements require less energy to produce. Studies have shown that 40% less CO2 is emitted during the production of BCSA cement than portland cement. This environmental benefit also makes it a very promising PC alternative. Before a new material can be used, designers need to understand the material’s properties. The goal of this study is to investigate the relationship between water content, citric acid dosage, and slump in BCSA mixes. A series of twelve mixes were performed with varying water contents and dosages of citric acid. Each mix was performed in a climate-controlled facility to account for any temperature variability since BCSA is sensitive to ambient temperature. All materials were gathered a day prior to mixing and placed in sealed containers overnight to ensure constant temperature conditions between batches. Air, water, and mix temperatures were recorded for all mixes to ensure consistency between trials. A slump test was performed on every trial per ASTM C143. Each trial had differing water contents. Slump increased with increasing water content, but the effect differs by retarder dosage, and at low water contents the slump is less sensitive to increases in water. Due to the different responses to water between BCSA and PC, new mix design guidelines are needed. Furthermore, the addition of citric acid can be considered a mandatory addition to BCSA mixtures, and the dosage influences slump.

Keywords

Alternative Cementitious Materials; Rapid Set Cement; Workability; Slump

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