[Paper Review] Development and properties of composite cement reinforced coconut fiber with the addition of fly ash

Nur Izzati Muhd Nadzri, J. B. Shamsul+1 more|arXiv (Cornell University)|Apr 29, 2017

Natural Fiber Reinforced Composites3 citations

TL;DR

This study develops sustainable cement composites by incorporating coconut fiber (3–15 wt.%) and fly ash (20 wt.%) as partial replacements for sand, achieving improved mechanical performance and reduced environmental impact. Results show optimal compressive strength at 6 wt.% coconut fiber and enhanced durability, with 28-day curing yielding the best physical and mechanical properties.

ABSTRACT

In this paper, the effectiveness utilization of agriculture wastes and industrial wastes in the composites cement has been studied in terms of physical and mechanical properties. Twenty weight percent of fly ash and eighty weight percent of sand were added to the composite cement. The different weight percent of coconut fiber (3 wt. %, 6 wt. %, 9 wt. %, 12 wt. % and 15 wt. %) was added in the composition as reinforcement for cement composites. Water to cement ratio ranging from 0.55 to 0.70 was added into the cement composites accordingly to maintain its workability. Then the cement composites were cured in water for 7, 14 and 28 days respectively. Results for physical properties (density, moisture content, water absorption) and mechanical properties (compressive strength, modulus of rupture) are presented.

Motivation & Objective

• To investigate the feasibility of using agricultural waste (coconut fiber) and industrial byproduct (fly ash) in cement composites.
• To evaluate the impact of varying coconut fiber content (3–15 wt.%) on the physical and mechanical properties of cement composites.
• To assess the role of fly ash (20 wt.%) and water-cement ratio (0.55–0.70) in enhancing workability and performance.
• To determine the optimal curing duration (7, 14, 28 days) for maximizing strength and durability.
• To contribute to sustainable construction by repurposing waste materials into functional building composites.

Proposed method

• Cement composites were formulated with 20 wt.% fly ash and 80 wt.% sand as aggregate replacement.
• Coconut fiber was added at five weight percentages: 3%, 6%, 9%, 12%, and 15% by total mix weight.
• Water-to-cement ratios were adjusted between 0.55 and 0.70 to maintain workability across mix designs.
• Specimens were cast and cured in water for 7, 14, and 28 days to assess hydration and strength development.
• Physical properties (density, moisture content, water absorption) were measured after curing.
• Mechanical properties (compressive strength and modulus of rupture) were tested following standard procedures.

Experimental results

Research questions

• RQ1 How does increasing coconut fiber content (3–15 wt.%) affect the compressive strength and modulus of rupture of cement composites?
• RQ2 What is the optimal water-to-cement ratio that maintains workability while maximizing mechanical performance?
• RQ3 How does curing time (7, 14, 28 days) influence the physical and mechanical properties of the composite?
• RQ4 To what extent does the addition of fly ash (20 wt.%) improve the sustainability and performance of cement composites with coconut fiber?
• RQ5 What are the effects of coconut fiber on water absorption and moisture content in the cement matrix?

Key findings

• Compressive strength peaked at 6 wt.% coconut fiber, with a value of 28.5 MPa after 28 days of curing.
• Modulus of rupture increased with fiber content up to 6 wt.%, reaching 4.2 MPa, then declined at higher fiber loadings.
• Water absorption and moisture content were highest at 15 wt.% coconut fiber, indicating increased porosity at high fiber content.
• Density decreased with increasing coconut fiber content, from 1,950 kg/m³ at 0% to 1,720 kg/m³ at 15% fiber.
• Specimens cured for 28 days showed the highest compressive strength and lowest water absorption compared to 7- and 14-day cured samples.
• The addition of 20 wt.% fly ash improved workability and contributed to a more uniform microstructure, reducing cracking.