Title: Aluminum Dross for Thermal Insulation and Acoustic Absorption of Alkali-Activated Slag Mortars

Author(s): Alaa M. Rashad, Abd El Fattah A. Mahmoud, and W. M. Morsi

Publication: Materials Journal

Volume: 119

Issue: 4

Appears on pages(s): 151-164

Keywords: acoustic absorption; alkali activation; aluminum dross; lightweight mortar; thermal conductivity

DOI: 10.14359/51734731

Date: 7/1/2022

Abstract:
The present research is the first attempt to investigate the opportunity of incorporating Egyptian aluminum slag (aluminum dross [Al-dross]) up to 50% into alkali-activated slag (AAS) lightweight mortars for thermal insulation and acoustic absorption purposes. Because expanded perlite (EP) is a standout among the effective materials in insulating, it was used as a fine aggregate. To increase the efficiency of thermal insulation and acoustic absorption, different foaming/blowing agents (0.5 and 4%) of hydrogen peroxide (H2O2) were incorporated. The results of density, compressive strength, total porosity, water absorption, thermal conductivity, and acoustic absorption of different mixtures were measured and compared with those containing 100% slag prepared with either EP or natural silica sand as a fine aggregate without any foaming/blowing agent. The selected samples were examined by different tools such as X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that introducing 50% Al-dross, without any foaming agent, could decrease the thermal conductivity and density by 23.12% and 14.83%, respectively. Including a high dosage of foaming agent resulted in low thermal conductivities (0.091 to 0.107 W/mK), low densities (209.3 to 544 kg/m3), high acoustic absorption coefficient, and acceptable compressive strength (0.99 to 1.67 MPa). The new product can not only save energy but also reduce the problem of by-products in landfills.