Mechanical properties of coconut shell-based concrete: experimental and optimisation modelling

Area of Science:

• Materials Science
• Civil Engineering
• Environmental Science

Background:

• Global waste accumulation necessitates sustainable material utilization in construction.
• Agricultural and industrial by-products are explored as replacements for traditional concrete aggregates.
• Coconut shell ash (CA) presents a potential eco-friendly aggregate substitute.

Purpose of the Study:

• To predict and optimize the use of coconut shell ash (CA) as a fine aggregate replacement in M30 concrete.
• To evaluate the impact of CA content on the mechanical properties of concrete.
• To develop and validate predictive models for concrete performance with CA incorporation.

Main Methods:

• Response Surface Methodology (RSM) for experimental design and optimization.
• Genetic Expression Programming (GEP) and RSM for developing predictive mathematical models.
• Analysis of Variance (ANOVA) to verify model performance and significance.

Main Results:

• Optimal CA replacement level for fine aggregate was determined to be 50%.
• Concrete with 50% CA exhibited enhanced compressive (46.2 MPa), tensile (3.74 MPa), and flexural (8.06 MPa) strength compared to control.
• GEP and RSM models demonstrated high prediction accuracy (R²=0.97 and 0.95) and low error (RMSE < 1.62 and 0.945).

Conclusions:

• Coconut shell ash (CA) is a viable and effective material for sustainable concrete production.
• Optimized CA incorporation significantly improves concrete's mechanical properties.
• GEP and RSM models provide reliable predictions for concrete performance, supporting further research and application.