Analysis of the effects of adding pyroclastic rock to red mud for the production of a baked building material in terms of its resistance to frost actions

Abstract

In the aluminum sector, approximately 130 million tons of waste red mud was produced in the last year. Such a high amount of wastes causes their storage areas to become a threat to the environment. Numerous studies have been conducted in the literature to eliminate this environmental threat. However, it is observed that these studies are mostly conducted on only a part of the waste, and there are few studies on the whole consumption of waste. Due to the said lack in the literature, it is thought that this waste can be utilized as a baked building material and consumed systematically. However, according to the literature and previous studies, it is observed that the use of the waste alone will not produce a quality building material. Therefore, otiose pyroclastic rocks were included within the scope of the study to be used together with the waste material. Accordingly, micronized pyroclastic rocks obtained from different regions were added to red mud at the proportions of 10, 20, 30, 40, and 50% by weight. Bentonite of 3% was added to mixtures to prevent capillary cracks. As a result of the preliminary experiments conducted on the baked building material samples obtained with the above-mentioned mixture ratios, two mixture types from each region with the highest compressive strength were selected. Physical and mechanical experiments were conducted on the samples to determine the resistance to frost actions—as an outer ambient condition with the most destructive effect—of the baked building materials (especially brick, etc. with the widest area of usage in outer walls and surface cover materials such as ceramic, clinker pavement, etc.) which will be obtained with these mixtures. As a result of the study, the optimum mixture type was determined to be the sample formed by adding 10% volcanic tuff around campus to red mud and baking it at a temperature of 1050 °C. Furthermore, different mixture types formed by adding the micronized pyroclastic material from other regions could reach sufficient values in terms of both compressive strength and frost actions. According to the results of the study, this material will fulfill the need for raw material as a building material resistant to frost actions and used in outer masonry. In this study, a process was obtained to eliminate a potential environmental problem, and a contemporary building material intended to be used as a sustainable building material was produced.