Ultra-High-Performance Concrete

ABSTRACT: Ultra-high performance concrete (UHPC) materials with outstanding material properties offer significant promise to transform infrastructure design and service life. Evolution of UHPC into a mainstream construction material would benefit from the resolution of issues relevant to the restrictive selections of finer aggregates/fillers, large heat of hydration and thermal stresses, high autogenous shrinkage and cracking potential, controlled thermal curing in field, relatively high initial (raw material/production) cost, and relatively high sensitivity to the chemical and physical attributes of cementitious materials and admixtures. The proposed project is focused on resolving these issues towards reliable and cost-effective production of UHPC infrastructure systems using commonly available materials and hardware. The proposed Phase I project will devise criteria and procedures for selection of UHPC raw materials, development of UHPC mix designs which are tailored towards locally available materials, and reliable, practical and scalable mixing, placement, curing and quality control of UHPC (including the selection of relevant hardware). Laboratory and pilot-scale field experiments will be conducted to refine these criteria/procedures, and validate their enabling role towards practical large-scale production and reliable field construction of major UHPC infrastructure systems. Strategies will be devised for construction of full-size UHPC test structures at Air Force test centers. BENEFIT: Successful accomplishment of the project goals would enable effective use of ultra-high performance concrete (UHPC) towards enhancement of the safety, structural efficiency, durability, sustainability, and initial and life-cycle economy of concrete-based infrastructure systems. The technical efforts to be undertaken in the project would yield specifications for material selection, mix design and practical/economical production of UHPC for use towards field construction of large infrastructure systems. The project would also produce substantial laboratory data and field experience with UHPC, highlighting its advantages in infrastructure applications. Diverse military and civilian concrete-based infrastructure systems would benefit from the use of UHPC; these include structures designed against extreme events (command centers, protective structures/shelters, earthquake-resistant structures, etc.), infrastructure systems subjected to severe exposures (offshore structures, bridges, parking structures, sewer pipes, etc.), runways, radioactive and hazardous waste containment systems, and high-rise buildings.