The Production of Lightweight Concrete Using Coconut Shell

Student: Arome David Onoja (Project, 2025)
Department of Civil Engineering
Federal University of Technology, Minna, Niger State

Abstract

This study investigates the production of lightweight concrete using coconut shells as partial
replacements for conventional coarse aggregates, aiming to assess strength characteristics,
feasibility, and develop effective mix designs. The particle size distribution analysis indicated that
the highest percentage of aggregates fell within the 14-20 mm range, ensuring proper grading.
Moisture content was found to be 2.66% for fine aggregates and 1.34% for coarse aggregates,
while specific gravities were 2.64 for fine, 2.77 for coarse, and 1.35 for coconut shells. The coconut
shell aggregate exhibited impact values between 1.31 and 1.34 and a crushing value of 1.159%,
well below the maximum of 30%, confirming its suitability for lightweight concrete. However,
workability decreased with increased coconut shell replacement; at a water-cement ratio of 0.5 and
a 1:2:4 mix, the control mix achieved a compressive strength of 17.26 N/mm² at 7 days, dropping
to 12.67 N/mm² with 12% replacement. After 28 days, the control mix reached 22.44 N/mm², with
lower strengths observed for higher replacements. While coconut shells effectively reduce density,
they also lead to significant reductions in compressive strength, highlighting the need for further
research and mix design adjustments for optimal application in concrete.

Keywords
lightweight concrete coconut shell sustainable materials coarse aggregate green construction eco-friendly concrete civil engineering
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