Graduation Year

2023

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

A. Gray Mullins, Ph.D.

Committee Member

Kevin R. Johnson, Ph.D.

Committee Member

Abla Zayed, Ph.D.

Committee Member

Michael J. Stokes, Ph.D.

Committee Member

Kingsley A. Reeves, Jr., Ph.D.

Keywords

Heat of Hydration, Mass Concrete, Temperature-induced Damage, Thermal Integrity Profiling, Thermal Modeling

Abstract

The term “mass concrete” characterizes a specific concrete condition that typically requires unique considerations to mitigate extreme temperature effects on a structure. Mass concrete has historically been defined by the physical dimensions of a “mass”-ive concrete element with the intent of identifying when differential temperatures may induce early-onset cracking, leading to reduced service life. More recently, in addition to differential temperature considerations, extreme upper temperature limits have been imposed by the American Concrete Institute to prevent long-term concrete degradation. Studies dating back to 2007 show shafts as small as 48 inches in diameter can exceed both differential and peak temperature limits; in 2020, augered cast-in-place piles as small as 30 inches in diameter exceeded both limits. This suggests the term “mass concrete” is misleading when considering today’s high-early-strength or high-performance mix designs. This study applies field temperature measurements and numerical modeling to investigate the effects of concrete mix chemistry, drilled shaft diameter, and environmental conditions on heat energy production during curing. Further, the outcome of this study focuses on developing criteria that combine the effects of both size and cementitious material content to determine whether unsafe temperature conditions may arise for a given design, as well as introduces the possibility of expanding existing quality assurance methods to confirm temperature limits are not exceeded post construction.

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