Design of binder system of eco-efficient UHPC based on physical packing and chemical effect optimization

This research presents an innovative design approach of binder system for eco-efficient UHPC (EUHPC) to achieve a densely compacted hardened paste by optimizing the physical packing and chemical effect of binder system. The influences of binder system composition on the compressive and environment impact of UHPC under different curing regime were studied. The hydration and microstructure of the designed EUHPC was investigated. The results show that the initial packing density and CaO/SiO2 ratio of the binder system have remarkable impact on the environmental impact and mechanical performance of UHPC. The optimal range of CaO/SiO2 ratio and packing density of binder system for eco-efficient UHPC is 0.9 to 1.2 and 0.7 to 0.73, respectively. According to this design method, the EUHPC with a very low carbon dioxide index (about 3.4 kg/MPa‧m3) and compressive strength of 150 to 200 MPa is successfully prepared.