Development and Application of High Performance Concrete and Ultra-high Performance Concrete
Feng Naiqian(Tsinghua University,Beijing 100084,China)
As the development of new technologies,which are the invention and application of new water reducer,the recovery and processing of ultrafine mineral powder,the development of fiber and the invention of new cement-based material,concrete has been developing rapidly,especially high performance concrete (HPC) and ultra-high performance concrete(UHPC),which are widely used in many projects. The research shows that reasonable mix proportion is important for UHPC preparation and the concrete strength at different ages is higher than design reference strength obviously. Furthermore,new UHPC has some characteristics of large viscosity,small flow velocity,long consumption for measuring slump and slump flow,which affect construction. In order to solve these disadvantages,some methods are put forward,such as controlling water consumption of per square meter,controlling slump loss,applying powder effect,and so on. Moreover,controlling water-cement and water-binder ratio can inhibit self-shrinkage cracks of UHPC.