Manufacturing of Sustainable Untreated Coal Ash Masonry Units for Structural Applications

Wasim Abbass; Safeer Abbas; Fahid Aslam; Ali Ahmed; Tauqir Ahmed; Agha Hashir; Amr Mamdouh

doi:10.3390/ma15114003

Manufacturing of Sustainable Untreated Coal Ash Masonry Units for Structural Applications

Materials (Basel). 2022 Jun 4;15(11):4003. doi: 10.3390/ma15114003.

Authors

Wasim Abbass¹, Safeer Abbas¹, Fahid Aslam², Ali Ahmed¹, Tauqir Ahmed³, Agha Hashir¹, Amr Mamdouh⁴

Affiliations

¹ Department of Civil Engineering, University of Engineering and Technology, Lahore 54890, Pakistan.
² Department of Civil Engineering, College of Engineering in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 16273, Saudi Arabia.
³ Department of Civil Engineering, National University of Computer and Emerging Sciences, Lahore 54000, Pakistan.
⁴ Architectural Engineering Department, Faculty of Engineering and Technology, Future University in Egypt, New Cairo 11835, Egypt.

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.

Keywords: efficient waste disposal; recycling of coal ash; sustainable construction materials.

Grants and funding

The current research was funded through the START RESEARCH GRANT (SRGP) No. 2409, “Development of Sustainable and Economical Coal Ash Bricks: Alternative to Conventional Burnt Clay Bricks” by the Higher Education Commission (HEC) of Pakistan.