A Low Thermal Conductivity of Lightweight Laterite-cement Composites with Cotton Wastes Fibres

The development of eco- friendly environmental and sustainable building materials having low thermal conductivity and optimal physic-chemical abilities ensuring passive thermal comfort is imperative in the global quest for the minimization of greenhouse-gases (GHG) emission and energy needs in homes. To attend this objective, the present work underlines the feasibility of using waste cotton fibres for the design of the lightweight laterite-cement composites with low thermal conductivity for structural applications. The final products were obtained by replacing laterite cement composite with cotton wastes fibres (0.3-0.6 wt%) and then uniaxial pressing around 14 MPa. The thermo-engineering and structural properties were performed using several techniques: X-Ray Diffraction (XRD), Environmental Scanning Electron Microscope (ESEM), Fourier Transform Infrared Spectroscopy (FTIR), mechanical properties as well as thermal conductivity. This process accounts for the optimum (0.78 W.m−1. K−1) structural material made with 6 wt% cement, 0.6 wt% cotton fibres and better packing density of laterites particles (50/50). Regardless of the particle size distribution of aggregates (laterite), the increase of cotton fibres content resulted in lowering mechanical performances. This is due to the creation of pores and the weakness adhesion between the cellulosic fibres and laterites particles within the matrix. In addition, the presence of cellulose within a matrix enhanced the crystallinity of cementitious phases (CASFH and CASH) of the end-products. The formulated samples with the reduction around 29% of embodied energy compared to the conventional materials, appears as a promising eco-friendly composite with good thermal comfort, small-embodied energy and low environmental impact through sustainable process.