Date of Award:

12-2025

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Civil and Environmental Engineering

Committee Chair(s)

Srishti Banerji

Committee

Srishti Banerji

Committee

Robert J. Thomas

Committee

Patrick Singleton

Abstract

Concrete is one of the most widely used construction materials in the world. However, over time, it can crack and deteriorate, especially on roads and bridges exposed to harsh weather and deicing salts. Inspired by the long-lasting durability of ancient Roman concrete, this study explores the self-healing capabilities of concrete incorporating quicklime (calcium oxide) aggregates to extend the service life of bridge decks. For this purpose, three concrete mixtures were developed using local materials: one without quicklime (C-Q 0%) and two with 2% (C-Q 2%) and 4% quicklime (C-Q 4%). These mixtures were tested for fresh properties, strength, durability, and crack-healing performance. To evaluate healing ability, three crack width ranges were studied to represent field variability: two microcrack ranges (100–200 µm and 200–300 µm) and one macrocrack range (300–550 µm). The pre-cracked specimens were exposed to cyclic water/air-dry and deicing salt solution/air-dry conditions, simulating typical environmental exposures for bridge decks. Crack healing was monitored in three stages: surface-level healing using optical microscopy and crack width microscope, internal crack depth healing via water flow tests and ultrasonic pulse velocity (UPV), and compositional analysis of filling products through SEM-EDS. Results showed that incorporating quicklime increased the stiffness of the concrete and reduced workability, primarily due to heat generation during mixing, which lowered the available water. Despite this, quicklime enhanced strength and durability, improving resistance to abrasion, freeze-thaw damage, and chloride penetration, although drying shrinkage increased with higher quicklime content. Also crack healing was faster and more complete with higher quicklime content. Besides quicklime content, initial crack size was found to be critical: specimens with smaller cracks healed faster and more completely than those with macrocracks. Exposure to deicing salt solution enhanced surface crack closure across all specimens and improved internal healing in specimens with larger crack widths. Conversely, healing was reduced in microcracked specimens exposed to deicing salt/air-dry cycles. While cyclic deicing salt solution generally improved surface closure in both micro- and macrocracked specimens, internal healing improvements were mainly observed in macrocracked specimens. Further research is needed to confirm the formation of healing products and clarify the specific influence of exposure conditions.

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