Effect of human hair on thermal conductivity of mortars

Hussein Nasreddine2^{2}, Thouraya Salem1,⋆^{1,\star}, Othman Omikrine-Metalssi2^{2}, Teddy Fen-Chong2^{2}
⋆^{\star} : salem@esitc-paris.fr
1^{1} ESITCT_C-Paris, 79 avenue Aristide Briand, 94110 Arcueil, France
2^{2} Univ Gustave Eiffel, Cerema, UMR MCD, F- 77454 Marne-la-Vallée, France
Mots clés : human hair fibers, mortars, mechanical properties, thermal conductivity, porosity
Résumé :

The main issue that affects the comfort of people’s spaces where they live and work nowadays is thermal insulation. Some products on the market can reach this parameter, but they are expensive and not eco-friendly. The purpose of this study is to examine the potential for using bio-based composite materials, in particular Human Hair Fibers (HHF), to adjust to the thermal properties of indoor spaces: HHF has a thermal conductivity of roughly 0.037 , making it a good thermal insulator. Human hair, which accounts for 50% of hair salon waste and is currently incinerated for the most part, has also an elasticity and a tensile strength equivalent to that of copper wire for similar diameters. This study examines the effect of human hair of approximately 2cm in length on the compressive strength, open porosity, and thermal conductivity of mortars containing 0%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, and 8% human hair by weight of cement. Hair fibers were collected from male barbershops and were sorted before being used in order to remove garbage. Their bulk density was 43.84 ± 3 kg/ without compaction and 112.22 ± 4 kg/ after compaction. It was found that the addition of HHF results in a decrease in thermal conductivity and compressive strength with an increase in open porosity. Adding 8% HHF allows to obtain a lightweight mortar having 1.2 thermal conductivity which is 37% less than the reference mortar at 28 days, 29.1 MPa compressive strength and 20.2% porosity compared to 36.4 MPa and 15.6% for the reference (standard mortar without human hair fibers). The use of human hair waste-based mortars in construction could thus contribute to a better insulation of building and reduce the environmental impact of human hair waste (hazardous gases released from combustion of human hair, non-biodegradable waste…).

doi : https://doi.org/10.25855/SFT2023-129

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