A new gap-graded particle size distribution and resulting consequences on properties of blended cement

摘要

To improve the properties of blended cement and utilize cement clinker and supplementary cementitious materials (SCM) more efficiently, a new gap-graded particle size distribution (PSD) based on close packing theory was proposed, then blended cements with the gap-graded PSD were prepared by mixing cement clinker and SCM fractions homogeneously. The experimental results show gap-graded blended cement pastes present a lower water requirement, a higher packing density, and a more homogeneous, denser microstructure than reference cement (prepared by co-grinding). As a result, both early and late properties of the gap-graded blended cements with only 25% clinker content can be comparable with those of Portland cement. This investigation supports that a high performance blended cement with low clinker content can be prepared using the gap-graded PSD and arranging a high activity SCM, clinker, and a low activity SCM (or inert filler) in the fine, middle and coarse fractions, respectively.