1. Defining UHPC notes from ACI 239 brainstorming session 17 October 2011

2. Internal fibers Durability High compressive strength Rossi defines: – More than 150 Mpa – Low w/c (maybe less than 0.22) – High cement content – May also add durability requirement (or low porosity) Performance definition ACI 239: UHPCDefining UHPC (notes)17 October 2011

3. “something that pushes construction envelope” FHWA definition (FHWA-HRT-11-038) – Cementitious composite material – Water cement ratio – Optimized powder gradation – Fiber reinforced – Compressive strength (>=150MPa) – Tensile strength (5 MPa sustained) – Discontinuous pore structure Toughness must be mentioned ACI 239: UHPCDefining UHPC (notes)17 October 2011

4. Creep limits Particle packing must be optimized (maybe a packing density requirement) Keep it short and arbitrary (must be functional and not obscured) Both terminology definition (short and broad) as well as a more flushed out understanding in a broader document Maybe 2-3 factors in the definition Durability comes with other properties ACI 239: UHPCDefining UHPC (notes)17 October 2011

5. JASCE also uses tensile capacity in def (5 Mpa) May include strain capacity or energy dissipation capacity Needs to based on more than just strength (or it would be HSC) Balance between specificity and succinctness in definition General definition may be different than definition in design guide Definition could be 3-4 components and then further defined by application ACI 239: UHPCDefining UHPC (notes)17 October 2011