摘要: |
The objectives of this research were to 1) monitor in-situ moisture and diffusivity for both conventional concrete and concrete containing pre-wetted lightweight fine aggregate (LWFA), 2) compare deck performance in terms of early-age cracking, compressive strength, and chloride ingress, and 3) compare concrete properties in terms of compressive strength, chloride permeability, elastic modulus, and water content in the laboratory using cylinders cast in the field at the time of deck construction. The research involved field and laboratory evaluations of four newly constructed bridge decks located in northern Utah, two constructed using conventional concrete and two constructed using pre-wetted LWFA to promote internal curing. Data from sensors embedded in the concrete decks indicate that the volumetric moisture content and electrical conductivity of the internally cured concrete were higher than those of the conventional concrete during the 2-year monitoring period. Laboratory data indicate that the internally cured concrete was weaker at 1 year following deck construction, passed less current in rapid chloride permeability testing, had a lower modulus in free-free resonant testing, and had a higher gravimetric moisture content than the conventional concrete. In the field, the internally cured concrete was weaker at 2 years in Schmidt rebound hammer testing and exhibited greater chloride concentrations at both 1 and 2 years than the conventional concrete. The conventional concrete bridge decks had more reflection cracking from the joints between the underlying pre-cast half-deck panels than the internally cured concrete decks. |