What question did this study set out to answer?

This research aims to evaluate the mechanical properties of concrete hollow blocks using coconut husk ash and crushed coconut shell as replacements for traditional materials.

February 19, 2026

Evaluating the Mechanical Properties of M20 Concrete Hollow Blocks with Coconut Husk Ash (CHA) and Crushed Coconut Shell (CCS) as Cement and Fine Aggregates’ Replacement

Key Points

This research aims to evaluate the mechanical properties of concrete hollow blocks using coconut husk ash and crushed coconut shell as replacements for traditional materials.
Developed five different mix designs with an M20 mix ratio using 5% CHA and 10% CCS replacements.
Manufactured 150 CHB samples and tested them for compressive strength, water absorption, and thermal conductivity.
Applied ASTM standards for assessing mechanical and thermal performance.
Conducted tests after 7, 14, and 28 days of curing.
CHA exhibited 73.97% SiO2 + Al2O3 + Fe2O3 by mass indicating good pozzolanic properties.
Mix C5-A0 achieved an 8.94% increase in compressive strength, while Mix C0-A5, with 5% CCS, decreased strength by 15.53%.
Demonstrated an inverse relationship between water absorption and compressive strength.
Identified a correlation between density and thermal conductivity.
Confirmed that a 10% replacement of CHA and CCS is recommended for optimal strength and thermal performance.

Abstract

Concrete is considered the second most widely used material in building construction. Its high demand quickly depletes natural resources, causing ecological imbalance. This study explores the potential of utilizing CHA and CCS as replacements for cement and fine aggregates in load bearing CHB. It characterizes the physical properties of CCS, chemical properties of CHA, and identifies the effective proportions of CHA-CCS for mechanical and thermal performance following ASTM standards. Five (5) different mix designs were developed using an M20 mix ratio, with CHA and CCS replacement levels of 5% and 10%, respectively. A total of 150 CHB samples were manufactured and tested for compressive, water absorption, and thermal conductivity after 7, 14, and 28 days of curing. The results demonstrate that CHA is a good pozzolanic material with 73.97% SiO2 + Al2O3 + Fe2O3 by mass. Mix C5-A0 shows the highest compressive strength by up to 8.94% and Mix C0-A5, with 5% CCS, substantially decreases strength by 15.53%. The results support the inverse relationship between water absorption and compressive strength, as well as the correlation between density and thermal conductivity. The study confirms that a 10% replacement of CHA and CCS results in a feasible combination of strength and thermal performance. However, exceeding this replacement level is not recommended as it decreases the strength of the block.

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Cite This Study

Sales et al. (Mon,) studied this question.

synapsesocial.com/papers/6996a85cecb39a600b3eeff4 https://doi.org/https://doi.org/10.1051/e3sconf/202669404003/pdf

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