Thesis
Assessing freeze-thaw damage of internally cured concrete using pre-saturated coal ash based fine lightweight aggregates
Master of Science (M.S.), Drexel University
Jun 2024
DOI:
https://doi.org/10.17918/00010691
Abstract
This study evaluates freeze-thaw durability of internally cured concrete using pre-saturated fine lightweight aggregates (FLWA). The aggregates used to manufacture concrete include laboratory-manufactured coal combustion ash FLWA (CCA-FLWA), commercially available FLWA for performance assessment and normal weight aggregate as reference samples. Utilizing a Longitudinal Guarded Comparative Calorimeter (LGCC) and acoustic emission sensors, the research subjected these materials to a series of controlled freeze-thaw cycles to investigate the impact of varying degrees of saturation (DOS) of 100, 95, 90, 85, and 80% on their structural integrity and durability. Ultrasonic Pulse Velocity (UPV) tests were employed to measure active acoustic emissions and calculate the damage index before and after the freeze-thaw cycles, providing a quantitative assessment of each concrete types. The results indicate that the critical DOS threshold, where significant damage occurs, lies between 78-80%. Notably, CCA-FLWA demonstrated enhanced durability, requiring a longer period of 47 days to reach critical saturation, thus suggesting a lower susceptibility to freeze-thaw damage compared to Stalite-FLWA and conventional concrete. This study underscores the importance of material selection in environments prone to freeze-thaw cycles and highlights the potential of using sustainable aggregates to improve concrete durability. The findings contribute to the field of civil engineering by providing insights into the behavior of alternative concrete materials under adverse environmental conditions. Examining the data, the control concrete exhibited the highest cumulative energy values, with an average of 1.95x10⁷ eu at 100% DOS, suggesting significant internal damage. The Stalite-LWA concrete showed lower cumulative energy, averaging 1.65x10⁷ eu at 100% DOS, indicating better resistance compared to the control. However, the CCA-FLWA concrete had the lowest cumulative energy, with an average of 5.14x10⁵ eu at 100% DOS, underscoring its superior durability.
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Details
- Title
- Assessing freeze-thaw damage of internally cured concrete using pre-saturated coal ash based fine lightweight aggregates
- Creators
- Bankole Tejuoso
- Contributors
- Yaghoob Amir Farnam (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- 28 unnumbered pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Civil/Architectural/Environmental Engineering (1970-2026); College of Engineering (1970-2026); Drexel University
- Other Identifier
- 991021890314604721