Potential use of Alfa fibers in construction material: Physico-mechanical and thermal characterisation of reinforced specimen

•Development of Alfa fibers reinforced specimen for using in non-structural lightweight construction field.•Adding Alfa fibers leads to a low decrease in compressive strength.•Substantial increase in flexural strengthening rate for specimen reinforced with Alfa fibers.•Specimen with 7% Alfa fibers exhibited a typical “composite” behaviour.•Change in failure mode of Alfa reinforced specimen from brittle to ductile behaviour.•Increase the thermal performances of specimen-based Alfa fibers. The viability of using Alfa fibers as reinforcement material for developing lightweight sustainable construction materials in compliance with the valorization of local by-products concept has been investigated in this work. The specimens were produced based on the mix of hydraulic lime binder (NHL5) and varied Alfa fiber amounts of 0 % (Control Specimen), 7 %, 11 %, and 15 % vol. as binder replacement. The hardened properties of Alfa reinforced specimens including dry density, porosity, compressive and flexural strengths, elastic behavior, and dry thermal conductivity at different temperatures were investigated. The results have indicated that the addition of Alfa induced a moderate reduction in compressive strength which in turn allows to increase the deformability of specimen. Therefore, the addition of Alfa fibers induces failure mode change of specimen from brittle to ductile behavior, which results in improvement of toughness capacity. Test-results also highlighted the flexural strength enhancement of reinforced specimen for optimal amount value of 7% fibers, which exhibits a typical “composite” behavior. The corresponding strengthening rate of 139.4 % higher is due to the several reinforcement mechanisms like the high tensile strength of Alfa fibers and their bond reinforcement to the binder matrix. This leads to promote the load transfer mechanism from binder matrix to fibers which results in supporting a part of applied load before post-cracking phase. However, the use of Alfa fibers will make the reinforced specimen performed as regards the thermal insulation, where the thermal conductivity-value satisfies the basic requirement for using the sample in lightweight construction field as insulating-bearing material, according to the RILEM “class III” recommendations.