Title: Multiscale Mechanical Investigation of Ternary Binders Incorporating Calcined Clay and Slag

Author(s): Imane Bekrine, Benoît Hilloulin, Ahmed Loukili

Publication: Symposium Paper

Volume: 362

Issue:

Appears on pages(s): 49-63

Keywords: calcined clay, mechanical properties, mercury intrusion porosimetry, microindentation, nanoindentation, slag

DOI: 10.14359/51740874

Date: 6/5/2024

Abstract:

Recently, considerable attention has been given to the use of calcined clays in cementitious systems due to their availability and the enhancement of concrete durability properties they can generate thanks to the pozzolanic reaction. However, the interpretation of the macro-mechanical behavior of cementitious materials incorporating calcined clays is still challenging, especially when combined with other supplementary cementitious materials, and an investigation at the microscale is required. To this end, micro and nanoindentation are local mechanical techniques that can be used to assess the micromechanical properties of these heterogeneous and complex systems.

In this study, three ternary systems with 30%, 45%, and 60% substitution of cement with calcined clay and slag are compared to a CEM I-based reference mix at 28 days, in terms of mechanical performance, pore structure, and micromechanical properties. Results show that compressive strength is higher/equivalent to reference mix up to 45% of cement replacement. In addition, the elastic modulus of the pastes assessed by micro indentation was found to decrease with the substitution ratio, while the creep resistance was enhanced. Finally, mercury porosity and nanoindentation analysis showed that the higher the replacement ratio, the higher the amount of CSH in the tested ternary cement blends.