Sustainable Concrete with Wood Ash and Recycled Clay Block Aggregate

Various environmentally friendly binders have been used to mitigate the negative environmental impacts of cement production and the negative effects of waste and construction materials being disposed of in landfills. Wood ash (WA) is one such alternative binder, which is extracted from fish grills and restaurants that dispose of it in landfills, causing environmental pollution. Studies have shown that, based on the chemical composition of WA, the strength and durability properties of concrete can be slightly improved by using WA as a cement substitute, with an ideal replacement ratio of 10% to 20% to achieve the highest compressive, tensile and flexural strength within this range. Additionally, Crushed Clay Blocks (CCB) can be used to replace Normal Coarse Aggregate (NCA) at replacement at rates of 0%, 50%, and 100%. This is to meet sustainable development requirements and maintain a clean and pollution-free environment. This paper provides a comprehensive overview of the properties of WA and its potential applications in conventional concrete using alternative, environmentally friendly materials such as CCB. The highest compressive, tensile, and flexural strengths were achieved at 10% WA substitution with 50% CCB, reaching (41.45, 3.47, and 4.90) MPa, respectively. It was observed that as the WA substitution ratio increased with the CCB substitution ratio, the strength properties of the concrete mixtures decreased, although they improved over time due to pozzolanic effects. This study recommends an optimal mixture of S6 (10% WA + 50% CCB), which exhibits a proficient balance between strength and resource efficiency. In conclusion, this research aims to use WA in the manufacture of non-load-bearing insulating building units.