Title: Mechanical Performance and Microstructual Investigation of Binary and Ternary Lime Binders with Silica Fume and Metakaolin

Author(s): Luca Penazzato, Rogiros Illampas, Ioannis Rigopoulos, Ioannis Ioannou, and Daniel V. Oliveira

Publication: Symposium Paper

Volume: 362

Issue:

Appears on pages(s): 164-178

Keywords: curing age; mechanical properties; mortars; natural hydraulic lime; scanning electron microscopy; supplementary cementitious materials; sustainable materials

DOI: 10.14359/51740881

Date: 6/5/2024

Abstract:

The increasing demand for sustainable building products with lower carbon footprints is a huge global challenge that can hardly be faced by conventional cementitious mixtures. In this context, the use of alternative primary binders, such as hydraulic lime, should be explored. Research in this direction should aim at the development of innovative eco-friendly materials with suitable mechanical performance. For the retrofitting of masonry structures, for instance, it may be necessary to improve their mechanical properties by incorporating supplementary cementitious materials (SCMs), further reducing, at the same time, their environmental impact.

This study investigates the effects of silica fume and metakaolin included either individually or together alongside natural hydraulic lime. The mechanical performance of such binary and ternary binders has been characterized in terms of flexural and compressive strength. Moreover, scanning electron microscopy (SEM) has been used to study the microstructure of the mixtures. Finally, a preliminary investigation concerning the effect of curing time in lime-based mixtures with combined silica fume and metakaolin has been performed to investigate the possible benefits of this approach. The results highlight the superior pozzolanic efficacy of silica fume compared to metakaolin and point towards the proper dosages of SCMs to achieve optimal mechanical performance.