Optimised mix design and elastic modulus prediction of ultra-high strength concrete

Abstract The use of ultra-high strength concrete (UHSC) could significantly increase the load-carrying capacity of a structural member, and thus reducing the amount of materials used as well as expanding the floor area of buildings due to a reduction in member size. Despite these benefits of UHSC, its practical applications are still limited because of its complicated and uneconomical manufacture. This study therefore investigates different mix designs for UHSC using conventional manufacture methods with commonly used raw materials. An experimental study was also conducted to determine the optimised mix design in terms of the manufacturing cost. Modifications to improve the strength of current UHSC mixes were also suggested. In addition, an empirical equation for predicting the elastic modulus of UHSC was proposed based on an experimental database newly collected from about 300 tests with the cylinder compressive strength in the range from 100 MPa to 200 MPa. By comparing with the equations from current design codes and existing equations, it can be concluded that the proposed equation is not only simple but also gives the best predictions among existing equations.