A gap-graded particle size distribution for blended cements: Analytical approach and experimental validation

To increase the packing density of blended cement paste, a gap-graded particle size distribution (PSD) was theoretically deduced and modified according to the wet density of actual paste. Then experiments were conducted to validate the hypothesis of improvement of the properties of blended cements by the gap-graded PSDs proposed. The experimental results show that the gap-graded PSD resulted in a decreased water requirement and an increased packing density of blended cement paste, and modified gap-graded PSDs gave further effects. The heat of hydration of gap-graded blended cement pastes released slowly in the first 24 h and increased rapidly afterward. The microstructure of gap-graded blended cements was much more homogeneous and denser than that of reference blended cement, therefore both early and late mechanical properties of low clinker gap-graded blended cements were improved significantly and even higher than those of Portland cement.

A gap-graded particle size distribution (PSD) for blended cements was proposed and modified according to the wet density of actual paste. Experimental results prove gap-graded PSD resulted in an increased packing density of cement paste, and modified ones gave further effect. Both early and late strengths of gap-graded blended cements were improved significantly due to homogeneous and dense microstructure.Figure optionsDownload as PowerPoint slideHighlights
► A gap-graded particle size distribution (PSD) of blended cement was proposed.
► The gap-graded PSD was modified according to the wet density of actual paste.
► Modified gap-graded PSDs resulted in an increased packing density of blended cement paste.
► Gap-graded blended cement pastes presented homogeneous and dense microstructure.
► Both early and late strengths of gap-graded blended cements were improved significantly.