Green prepacked foam concretes against environmental attacks: The role of waste aluminum shavings, cooling methods and binder modifications

Abstract

Foam concrete has become innovative recently due to its fire safety and sustainability advantages. Foam concrete is the focus of researchers as an alternative to traditional concrete due to its low density, high thermal insulation, lightness and environmentally friendly advantages. However, studies on the resistance performance of aluminum-added foam concrete against both high temperature and acid attack are limited, and there is a significant gap in the literature in this area. This study investigates the effect of using granulated blast furnace slag (GBFS) and fly ash (FA) in different proportions instead of cement on the performance of foam concrete containing fixed proportions of aluminum and foam. Fresh properties (flowability), physical properties (fresh unit weight, apparent porosity, water absorption and oven dry density), mechanical properties (7, 28, 90-day compressive strength and 7, 28, 90-day flexural strength), transport properties, and thermal conductivity parameters of foam concrete were investigated. Moreover, the performance against high temperature exposure and acid attack, as well as the effect of cooling methods (air and water) after high temperature on the performance of foam concrete, were investigated. In case of cooling with water, the compressive strength of samples exposed to high temperatures of 300, 600, and 900 °C decreased by up to 40 %. Samples containing FA preserved both early age and compressive strength more effectively after 600 °C temperature. Although GBFS was effective on early age strength, it deteriorated more at high temperatures. In SEM images, cracks, gaps, and the development of ettringite and Portlandite phases formed in the matrix were observed in detail. In SEM images, cracks, gaps, and the development of ettringite and Portlandite phases formed in the matrix were observed in detail. SEM findings have revealed that fly ash and slag additives, in particular, increase foam concretes' chemical and thermal durability. This study provides an optimum design for the performance of aluminum-added foam concrete against thermal and chemical effects. The results show that foam concrete can be used in sustainable field construction applications.