Phase and microstructure evolutions in LC3 binders by multi-technique approach including synchrotron microtomography

Limestone Calcined Clay Cements, LC3, are attracting a lot of attention as it is possible to reduce the clinker factor by 50%, which means cement CO2 footprint reduction 40%. This compatible with maintaining mechanical strength performances after one week, if kaolinite contents raw clays above ~40 wt%. Durability properties also maintained or even enhanced. Here, used multi-technique approach understand phase and microstructure developments. From thermal analysis, partial limestone reactivity proven. Chiefly, high-resolution synchrotron microtomography has been employed, for first time in these systems, characterize their microstructures. The measured total porosities, within our 1 ?m spatial resolution (voxel size 0.32 ?m), were 16.6, 10.0 2.4 vol% at 7, 8 60 days hydration, respectively. Pore connectivity strongly decreases hydration due chemical reactions producing new phases filling pores. 6-connected porosity fractions 92, 78, 9% days. pores investigated Rietveld quantitative analysis 27Al MAS-NMR.