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Quantifying the efficiency and quality of air void distributions in concrete

Becker, Hope Hall
This work establishes new ways to measure and examine the air bubble distribution within concrete. This is important to provide freeze thaw durability and resistance to oxychloride formation. These bubbles decrease the fluid pressure on freezing and crystal formation. The quality of the air void distribution is important to maintain from mixing the concrete until it is hardened to ensure durability. If these bubbles are significantly modified or destroyed during construction or are lost over time, then they cannot provide the needed protection. This work studies concrete mixtures immediately after mixing, during placement, after hardening, throughout freezing and thawing cycles, and soaked in chloride solution through temperature changes. The SAM (AASHTO TP 118), Hardened Air Void Analysis (ASTM C), Freeze Thaw Durability Factor (ASTM C666), and Micro computed tomography (Micro-CT) are all utilized to verify and establish the quality of the air void system within concrete mixtures [1-3].