*********************************
There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
*********************************
School of Civil and Environmental Engineering
Ph.D. Thesis Defense Announcement
Assessment of Mass Concrete Thermal Prediction and Failure Criteria: Novel Models, Evaluation Methods, and Case Studies
By
Luna E. Al-Hasani
Advisor(s):
Dr. Kimberly Kurtis (CEE), Dr. Russell Gentry (ARCH)
Committee Members:
Dr. Jason Brown (ARCH), Dr. Yong Cho (CEE), Dr. Iris Tien (CEE)
Date & Time: Friday April 15, 2022, at 1:00 pm
Location: https://tinyurl.com/2s3tswcy
The durability of massive concrete structures may be compromised by delayed ettringite formation (DFE) and thermal cracking. These issues are the result of the high internal temperatures and temperature differences that develop within the concrete elements during curing as a result of the heat of hydration. Designers have sought to develop mixture designs and construction technologies to control DEF and thermal cracking by specifying maximum allowable thresholds for both. The overarching aim of this dissertation is to provide recommendations for best-practices for the design and construction of mass concrete to ensure the durability of the structural elements, without resorting to stringent and costly thermal control measures during construction. This can be accomplished by adopting a robust approach for mass concrete thermal modeling, and transitioning to performance-based temperature difference thresholds by addressing the function and performance of concrete structural elements. In this work, two methodologies were presented and validated for heat of hydration modeling and subsequent simulations of mass concrete internal temperatures and temperature differences: an experimental approach using isothermal calorimetry, and a probabilistic machine learning approach, both of which gave accurate results when validated through the thermal modeling of several case studies. Moreover, a framework has been proposed for finding performance-based temperature difference limits by considering the time and temperature-dependent development of mechanical properties, and case-specific creep and internal restraint factors. The results have confirmed that the current prescribed temperature-difference threshold for mass concrete is conservative. Findings have demonstrated the need for a more robust, detailed, and performance-based framework for the analysis, design, and construction of mass concrete structures, to advance structural durability while promoting conservation of resources.
