Title: Phase Compositions and Strengths of One-Year-Old Ternary Cement Composites

Author(s): L’udovít Krajci, Ivan Janotka, Michal Bacuvcík, and Subhash C. Mojumdar

Publication: Symposium Paper

Volume: 303

Issue:

Appears on pages(s): 119-132

Keywords: cement; metakaolin; diatomite; pozzolan; one-year strength; pore structure; microstructure

DOI: 10.14359/51688129

Date: 6/1/2015

Abstract:
Ternary cement composites consisting of metakaolin sand (MKS), natural clayey diatomite (CD) and calcined clayey diatomite (CCD) with various reciprocal combinations up to 15 wt. % and water-cementitious materials ratio of 0.5 were studied. Phase composition and strength of one-year old composites cured in water at (68 ± 33.8) °F [(20 ± 1) °C] were compared with reference portland cement (PC) paste. Compressive strengths of ternary cement composites on (MKS + CD) and (MKS + CCD) bases exhibited notable similarity and were slightly higher than those of reference paste. Pozzolanic reaction resulting in portlandite consumption and sustained formations of calciumsilicate (CSH) and calciumaluminate (CAH) hydrates was confirmed in the studied composites. Micropore and total pore median radii were reduced opposite to those observed in reference paste. Calcination of natural CD towards CCD formation was found redundant because of the considerably similar character of CD and CCD effect on the formed phase composition and strength uptakes.