Comparative study on the chemical and physical filling effects of binder materials in Green Ultra-High Performance Concrete and Ultra-High Performance Concrete

The development of Green Ultra-High Performance Concrete (GUHPC) is one of the primary approaches to combat global warming in the construction industry and has received widespread attention. Accurately quantifying the physical and chemical filling effects of binder materials can aid in the development of more efficient design methods for GUHPC. The hydration and microstructure development of GUHPC were investigated by a combination of the isothermal calorimetry, mercury intrusion porosimetry (MIP), thermogravimetry (TG), X-ray diffraction (XRD) and backscattered electron microscopy (BSEM). The physical and chemical filling effects of each binder material on the porosity of paste were quantified. The results indicated that both the physical and chemical filling effects of the binder materials made essential contributions to the porosity. Compared with in UHPC, supplementary cementitious materials (SCMs) play a better chemical and physical filling role in GUHPC. More attention needs to be paid to the chemical filling effect of mineral admixtures in the design of GUHPC. Reasons for limiting the ability of binder materials in GUHPC to achieve better chemical filling effects were discussed.