Incorporating black dust into autoclaved aerated concrete wall for heat transfer reduction

Abstract

Black dust is a waste product of the automotive refinishing industry in Thailand. Instead of removing black dust by landfill disposal, an innovative approach of utilizing black dust as the mixture for the preparation of autoclaved aerated concrete (AAC) was investigated. Results demonstrate that black dust is able to provide higher compressive strength and more extended time lag than conventional materials. The chemical properties of black dust were investigated by using X-ray fluorescence analyzer. The use of black dust content of 20 wt.% replacement of fine sand was the optimum composition, which possessed a low density of around 0.58 g·cm^-3, a maximum compressive strength of ~ 4.6 MPa and the lowest proportion of thermal conductivity of 0.120 W·m^-1K^-1. The AAC incorporating the optimum black dust content significantly increased in the thermal effectiveness of the building materials by extending approximately 25% the time for the heat wave to flow through the exterior wall to the interior wall, reducing ~ 33% heat flux and achieving ~ 4.7% lower room temperature when compared with the conventional AAC.