Hydration characteristics and mechanical performances of LC3 binders with spanish kaolinitic calcined clays

Abstract

Limestone Calcined Clay Cements (LC3) are binders with complex phase development and microstructures. Although the hydration chemistry of these cements are being widely researched [1], due to the clay mineralogy variability, more studies are needed to build full knowledge. The use of calcined kaolinitic clays as SCMs in Portland cement is one of the best approaches, as metakaolin shows exceptional pozzolanic properties. Here, we report a summary of our ongoing research dealing with LC3 binders based on Spanish calcined clays with different kaolinite content. The kaolinite contents [2], jointly with the particle size of the calcined clays [3] will determine the reactivity, and consequently, the mechanical performances. Initially, a selection of three commercially available Spanish kaolinitic clays was carried out. Mineralogical and elemental analyses were obtained by Xray powder diffraction (XRPD) and X-ray fluorescence (XRF), respectively, are elsewhere [3]. The clay provenance and estimated average kaolinite contents are given in Table 1; the latter was obtained through the combination of three methodologies (LXRPD, thermal analysis and XRF) [3].