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Non-Destructive Evaluation of a Newly Constructed Bridge Deck Affected by Plastic Settlement
Plastic concrete settlement during the early curing stages presents a significant risk to the structural integrity of new bridge decks. It can lead to exposed rebar, inadequate concrete cover, and delamination, compromising the bridge’s durability, safety, and structural stability. Traditional visual inspection typically used to evaluate bridge decks affected by plastic settlement is subjective, labor-intensive, and often fails to detect subsurface defects. To curb these limitations, this study employed Non-Destructive Evaluation (NDE) to investigate plastic settlement on the newly constructed US 75 Pedestrian Underpass at Northaven Trail in Dallas, Texas. The structure is a 201-foot-long cable-suspended arched bridge. It exhibited visible rebar marks on the deck and raised concerns about the potential internal delamination and rebar cover inadequacy. Subsequently, Ground Penetrating Radar (GPR) and Impact Echo (IE) were used to assess the adequacy of rebar covers and to detect and quantify delamination caused by plastic settlement, respectively. The GPR findings revealed that over 60% of the deck’s rebar cover failed to meet the AASHTO (2020) specifications. In contrast, the IE assessment indicated minimal delamination in most of the scanned bridge deck area.
