The Effect of Nano Materials on HVFA Mixtures

Abstract

The interest in more sustainable concrete mixtures with the supplementary cementitious materials like fly ash has increased significantly in the past few years. Nevertheless, the early age properties development (setting and strength gain) of these mixtures still remains a challenge and, in most cases, prevents their efficient use in practice. In this paper, nano-aluminosilicates were used to improve early age properties of high volume fly ash (HVFA) mixtures. This paper presents results of several different paste and mortar mixtures where 60 % (by volume) of the portland cement was replaced by fly ash (Class C or Class F) and 1 % of amorphous nano-aluminosilicates with different silicon-aluminum ratios. Paste mixtures were characterized by measuring heat release and setting times and the compressive strength was evaluated in mortar mixtures in order to determine the optimal silicon-aluminum ratio for the cementitious materials used in the study.