Feasibility of Non-Proprietary Ultra-High Performance Concrete (UHPC) for Use in Highway Bridges in Montana
Ultra-high performance concrete (UHPC) has mechanical and durability properties that far exceed those of conventional concrete. However, using UHPC in conventional concrete applications has been cost prohibitive with its price about 20 times the cost of conventional concrete. The overall objective of the Phase I research was to develop and characterize economical non-proprietary UHPC mixes made with materials readily available in Montana. This objective was achieved by first identifying and obtaining suitable/economical materials to be used in UHPC. Specifically, the materials identified and used in this research were simply Type I/II Portland cement (from Trident, MT), class F fly ash (from North Dakota), fine masonry sand (from Billings, MT), silica fume, and high range water reducer. UHPC mixes were then developed/characterized/optimized using a statistical experimental design procedure (response surface methodology).
The research proposed will build on the non-proprietary UHPC research completed at MSU, and focus on ensuring the successful application of this material in bridge field-cast joints. Specifically, this research will investigate several items related to the field batching of these mixes, and the potential variability in performance related to differences in constituent materials. Further, rebar bond strength and the subsequent effect this has on development length will be investigated.