Promising Early Age Evaluations of Fly Ash - Calcined Marl - OPC Ternary Cement

Abstract

The search for new supplementary cementing materials (SCM) creates opportunities to using new materials such as calcined clays and marl. However, such changes require a transition period, where introduction of new SCMs are most successful when they can be coupled and employed with the existing materials.

For this purpose, a series of ternary mixes employing fly ash (F), calcined marl (C) and ordinary Portland cement (OPC) was evaluated against mono- and binary mixes of the components. It was found that due to the complementary water demand of fly ash and calcined marl, forming pastes made of ternary blends of FC-OPC leads to better rheology than pure OPC pastes, particularly when a F:C ratio of 1:1 was present, even up to 60% replacement of OPC. Any increase in C results in a decrease in flowability, while increasing the F proportion resulted in higher flow, with eventual bleeding. This was coupled with a synergetic improvement in the early age of hydration of the ternary mixes as compared to mono- or binary mixes.

The results here indicate that ternary mix of fly ash-calcined marl-OPC can pave the way for future cementing systems, where it can be easily utilized even in the transition stage and allow the successful implementation of this material.