Influence of Coconut Shell Aggregate Size Variation on the Durability of Concrete
Philip Boamah
*
Department of Construction Technology and Management, Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development, Kumasi, Ghana.
Emmanuel Appiah-Kubi
Civil Engineering Department, Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development, Kumasi, Ghana.
Joseph Ignatius Teye Buertey
Department of Built Environment, Pentecost University, Accra, Ghana.
*Author to whom correspondence should be addressed.
Abstract
Concrete is a widely used material globally. As demand grows, environmental concerns about its production have become more urgent. This study examines the effects of coconut shells as partial replacements for coarse aggregates in concrete on its durability, focusing on abrasion resistance, magnesium sulphate attack resistance, and sodium chloride attack resistance.
The study was conducted at the AAMUSTED construction laboratory within 12 months. The West Coast tall coconut species was employed in the study. Sieved crushed coconut shell aggregates of various sizes: 12.5- 9.5 mm, 19-12.5mm, 25-19mm, and 37.5-25 mm were used, constituting 10% of the total coarse aggregate.
The aggregates were mixed with a 1:2:4 mix ratio. Three coconut shell aggregate size variation concrete mixes and three samples each were cast and cured for 7,14,21, and 28 days before exposure to chemical attack.
The study found that 37.5 - 25mm coconut shell aggregate size replacement improved the concrete's resistance to abrasion by 1.7% compared to 1.32% for smaller size replacement (12.5mm – 9.5mm). The percentage reduction in Compressive strength after NaCl attack was 6.87% for 12.5mm – 9.5mm replacement and 15.70% for 37.5 – 25mm replacement. The study concludes that using coconut shell aggregate in concrete is a sustainable alternative to natural aggregates, supporting eco-friendly construction practices, especially in regions with a plentiful supply of coconut shells. This method reduces waste while improving concrete's surface durability and chemical resistance, making it ideal for specific applications. The results of the tests indicated that the durability properties of coconut shell-replaced concrete specimens were comparable to conventional concrete, and all durability properties of coconut shell-replaced concrete had a reduction in their strength properties as compared to normal concrete.
Keywords: Coconut shells (CS), abrasion resistance, magnesium sulphate attack, sodium chloride attack