Auto-coherent homogenization applied to the assessment of thermal conductivity: Case of alternative binders in cementitious composites

Climate change is an environmental issue that has come to the fore and building sector is the main contributor in the global warming. It has become crucial to insert sustainable materials, like natural fibers, in the elaboration of materials used to build the constructions like cement and/or its derivatives. This is a green way to develop innovative insulating materials and reduce energy consumption of dwellings. In the present study, the auto-coherent homogenization method (HAC) and the law mixture principles have been used to assess the theoretical thermal conductivity using on previous experimental data obtained by the team: sugar cane bagasse fibers, raw-material (FR) or pyrolyzed (FP), were incorporated in three cementitious matrices (CLA (CEM II 32.5 N), POU15BAG5 and POU15BAM5 (80 % of CEM I 52,5 N, 15 wt% of natural pozzolan and 5 wt% of ashes from respectively sugar cane bagasse and bamboo)). For the first time, the thermal conductivity of binders of non-conventional composite materials has been estimated. ANOVA tests have shown that the theoretical thermal conductivity of the ternary matrix POU15BAM5 was smaller than the one of POU15BAG5 (respectively 17 % at 180 days of aging and 6 % at 360 days of aging). • Estimation of the matrix’ theoretical thermal conductivity λ regarding some factors. • Auto-coherent homogenization to assess cementitious composites’ theoretical λ. • Maxwell-Eucken’s theory to calculate the theoretical λ of the alternative binders. • Prediction of λ for different matrices mainly for alternative new binders.