Durability and acoustics of concrete with slag of cupola furnace as fine aggregate replacement

Abstract

In this paper, it was evaluated the performance of concrete with crushed slag of cupola furnace (SCF) as sand replacement in percentages of 0 %, 10 %, 15 % and 20 %, subjected to accelerated chemical attacks of carbonation, sulfation and alkali-aggregate reaction (AAR). The sound absorption characteristics of the material were determined through the sound absorption coefficient (α), and the noise reduction coefficient (NRC). Carbonation was evaluated through a closed camera with the 70 % concentration of carbon dioxide and conditions of relative humidity between 50 % and 70 %. The results indicated that the penetration depth of CO2 is lower when greater the percentage of substitution is. To accelerate the attack by sulfates, specimens were immersed in aqueous solution of sodium sulfate anhydrous (Na2SO4) 1N with cycles of wetting and drying. It determined that the impairment presented in concrete paste is directly proportional to the percentage of sand replacement. The acceleration of the AAR in the concrete was carried out by immersing specimens in an aqueous solution of sodium hydroxide (NaOH) for 16 days. The test concluded that the inclusion of SCF is not favorable for AAR. The measurement of sound absorption coefficient was taken by the method of impedance tube, relating minimum and maximum values of stationary wave amplitude. The results showed that SCF with higher sand replacement are favorable for the noise absorption in buildings.