Manufacturing of Sustainable Untreated Coal Ash Masonry Units for Structural Applications

Abstract

Burnt clay bricks are one of the most important building units worldwide, are easy and cheap to make, and are readily available. However, the utilization of fertile clay in the production of burnt clay bricks is also one of the causes of environmental pollution because of the emission of greenhouse gases from industrial kilns during the large-scale burning process. Therefore, there is a need to develop a new class of building units (bricks) incorporating recycled industrial waste, leading toward sustainable construction by a reduction in the environmental overburden. This research aimed to explore the potential of untreated coal ash for the manufacturing of building units (coal ash unburnt bricks). Coal ash unburnt bricks were manufactured at an industrial brick plant by applying a pre-form pressure of 3 MPa and later curing them via water sprinkling in a control shed. Various proportions of coal ash (i.e., 30, 35, 40, 45, 50, and 55%) were employed to investigate the mechanical and durability-related properties of the resulting bricks, then they were compared with conventional burnt clay bricks. Compressive strength, flexural strength, an initial rate of water absorption, efflorescence, microstructural analysis via scanning electron microscopy, and cost analysis were conducted. The results of the compressive strength tests revealed that the compressive strength of coal ash unburnt brick decreased with an increase in the content of coal ash; however, up to a 45% proportion of coal ash, the minimum required compressive strength specified by ASTM C62 and local building codes was satisfied. Furthermore, bricks incorporating up to 45% of coal ash also satisfied the ASTM C62 requirements for water absorption. Coal ash unburnt bricks are lighter in weight owing to their porous developed microstructure. The cost analysis showed that the utilization of untreated, locally available coal ash in brick production leads us on the path toward more economical and sustainable building units.

Construction and Building Materials: Masonry Structures and Reinforced Concrete Structures

“…Tests on masonry units are presented in the paper [5]. Abbass, Abbas, Aslam, Ahmed, Ahmed, Hashir, and Mamdouh focused on manufacturing new masonry units with recycled coal ash.…”

“…The numerical validation of the model of wall connections was proposed only in the paper [21]. Tests on component elements [2,4,5,7,9,11,14,21], and on repairs and strengthening of constructions [10,13,19,24] were conducted for both reinforced concrete and masonry structures.…”

Exploring the Mechanical and Microstructural Characteristics of Recycled Concrete Hollow Blocks: Transforming Waste into Valuable Resources

“…SEM and EDX image of the CBA taken in the study is shown in Fig 7 and Due to its low pozzolanic activity, calcium oxide could be a barrier to its application in cementitious systems. CA used in the study is classified as class C ash because the sum of SiO2+ Al2O3 + Fe2O3 is below 70 % 32) . Bottom ash is easier to compact under loading since it has a more porous and vesicular structure due to its larger proportion of unburned carbon.…”

Synthesis of Zeolites from Coal Fly Ash Using Alkaline Fusion and Its Applications in Removing Heavy Metals

“…Currently, CFA is used mainly as building material in the cement and concrete sectors and as soil stabilization for roads, embankments and ash dyke raising, landfill liners or covers, in mine filling, in bricks, blocks and tiles, agriculture, and others [ 6 , 7 , 8 ]. However, these applications reduce solid waste but do not fully exploit the potential uses of this rich resource [ 9 , 10 ].…”