A review on ultra high performance concrete: Part I. Raw materials and mixture design

• Four theoretical principles for production of UHPC, including reduction in porosity, improvement in microstructure, enhancement in homogeneity, and increase in toughness, are reviewed.
• Effects of different raw materials on performance of UHPC are summarized.
• Mixture design, sample preparation, and curing regimes are discussed.
• Use of conventional materials and common technology are trends for production of UHPC.

Ultra high performance concrete (UHPC) refers to cement-based materials exhibiting compressive strength higher than 150 MPa, high ductility, and excellent durability. This paper reviews the theoretical principles, raw materials, mixture design methods, and preparation techniques for UHPC. Reduction in porosity, improvement in microstructure, enhancement in homogeneity, and increase in toughness are four basic principles for UHPC design. Raw materials, preparation technique, and curing regimes have significant influence on properties of UHPC. The use of widely available supplementary cementitious materials, such as fly ash and slag for partial/complete replacement of cement and silica fume, could significantly reduce the materials cost without sacrifice of strength. The use of high temperature curing results in denser microstructure and better performance than room temperature curing does, but obviously limits its applications of UHPC. Thus, preparation of UHPC using widely available raw materials, common technology, such as conventional casting and room temperature curing, are trends for production of UHPC.