Characterization of Wadi Mashashe deposits (Egypt) incorporating wastes for the potential utilization as alkali-activated binders

Abstract

The purpose of this article is to characterize and examine the possible uses of Mashashe deposits (clay [MC] and its overburden [OD]), which incorporate industrial wastes (cement kiln by-pass [CKD], water-cooled slag [WCS]), to create alkali-activated binders. For this purpose, six mixes (M-1 to M-6) were investigated, while the calcined clay (MCC) was partially replaced by CKD and calcined overburden deposits (COD) at different ratios (0%, 1.5%, and 3 wt.%). Additionally, a NaOH solution containing 10 and 8 M of alkali was utilized. The raw clay sample and its overburden were collected from Wadi Mashashe area (north-central Sinai, Al-Arish city, Eastern side of Gabal Libni, Egypt), then were calcined [MCC, COD] at 850°C to increase the reactivity. The used materials and lab-made cured specimens were characterized by various analytical methods and techniques including XRF, thermal analyses, infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The physio-mechanical characteristics and fire durability test results were determined after the hardened laboratory cubes were cured for 7 and 28 days. According to the results, the ratio of CKD or COD of 1.5% (M-3 and M-5) revealed the most suitable mixture used in manufacturing the alkali-activated binder. The most promising results were for mix M-1 followed by mix M-5, while the worst results were for mixes M-2 and M-6. Therefore, mixes of M-1, M-5, and M-3 have the most potential usage to produce alkali-activated binders.