Mitigation of Autogenous Shrinkage of Ultra-High Performance Concrete by Rice Husk Ash

Ultra-high performance concrete(UHPC) becomes one of promising concretes in the last decade due to its excellent per-formance such as ultra high strength,low permeability and very good durability.However,like high performance concrete,the UHPC is also subjected to high autogenous shrinkage due to a great amount of cement and silica fume used.The reduction of the autogenous shrinkage is an important task in the field of cement and concrete research.In this work,the rice husk ash(RHA) as an agriculture waste was used to mitigate the autogenous shrinkage of UHPC.The results show that RHA with a high content of amorphous SiO2 and the special porous structure.When 20% RHA with particle size of 5.6 μm was used,the shrinkage of UHPC was eliminated after curing for 15 d.RHA used in UHPC can reduce the cost,improve the early age properties of the UHPC and increase the environ-mental benefits because RHA has high content of atmorphous SiO2 and special structure.