**1. Introduction**

Bricks are widely used in construction projects as they possess beneficial characteristics such as low cost, high durability, and ease of handling [1]. Clay is the primary raw material used in brick production. For brick manufacturing, almost 340 billion tons of clay are used annually [2]. The increasing clay use as a resource for manufacturing bricks has caused an alarmingly high degree of variance in this natural material [3]. This has therefore led several researchers to find alternative resources or ways to recycle the wastes produced by various industrial processes. As a result, many waste materials have been used in brick manufacturing, including marble dust [4], sludge from water treatment plants [5], fly ash [6], sugarcane bagasse ash [7], rice husk ash (RHA) [8], waste glass powder [9], sawdust [10], quarry dust [11], and eggshell powder (ESP) [12]. The properties of clay must be altered by the additives physically and chemically within a specific range, and they must not adversely affect the clay's strength and durability [13].

Fly ash is a typical clay component generated when coal is burned in coal-fired power plants. It is a varied substance with a glossy appearance made of mullite (alumina and silica) and iron oxides (hematite and magnetite) [14]. Its elemental composition is similar to that of brick soils. Bricks' strength can be increased and water absorption reduced by adding fly ash to clay [15,16]. RHA is a potential source of Amphorous reactive silica released by the combustion of rice hulls [17]. It has excellent thermal insulation and keeps the temperature stable. According to a study by Ramasamy [18], adding a small amount of RHA will increase the material's compressive strength. Food processing firms produce tons of eggshells as waste, which has led to environmental issues because of their inappropriate disposal in our environment [19]. The calcium carbonate in ESP dissolves in different acids and has a chemical composition similar to limestone [20]. ESPs are potential substitute raw materials for clay brick production [12].

**Citation:** Ramakrishnan, K.; Chellappa, V.; Chandrasekarabarathi, S. Manufacturing of Low-Cost Bricks Using Waste Materials. *Mater. Proc.* **2023**, *13*, 25. https://doi.org/ 10.3390/materproc2023013025

Academic Editors: Katarzyna Mróz, Tomasz Tracz, Tomasz Zdeb and Izabela Hager

Published: 15 February 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

A study by Dhanapandian and Gnanavel [21] indicated that up to 20% of waste marble powder improved water absorption. Adding waste marble to clay reduces the fire temperature without affecting the brick's properties [22] and thus lowers the production cost and saves energy. The bricks' physical strength at high temperatures was increased by including waste marble [23]. The fluxing effect of these wastes at higher temperatures boosted several brick properties, most notably flexural strength, compressive strength, and bulk density [4]. Past studies, e.g., from the authors of [24], have proven that waste marble powder may be used inexpensively in clay bricks. Quarry dust is produced by cutting and grinding the stone. Depending on the quarry fine dust's physical and chemical properties, it may be used to produce bricks as a filler, a replacement for clay, a colorant, a fluxing agent, or even body fuels [25]. Quarry dust addition improves the bricks' durability [26]. The potential use of naturally occurring wastes, readily accessible and inexpensive, is becoming increasingly more important in reducing building material costs without sacrificing quality. Given the above, this study investigated the behavior of bricks made by replacing clay with waste materials such as ESP, RHA, fly ash, quarry dust, and marble dust and estimated the cost of brick production.
