Development and Experimental Evaluation of Agave americana Fibre-Reinforced Concrete Bricks: Effect of Fibre Content on Strength, Workability & Moisture

Abstract

Concrete is strong in compression but brittle and weak in tension, and plantbased fibres are being explored as sustainable supplementary reinforcement for cement-based products. Cement-based bricks reinforced with Agave americana fibres have received comparatively little attention. This study investigated how Agave americana fibre content affects the properties of M20-grade concrete specimens prepared for brick applications. Retted, alkali-treated fibres cut to approximately 40 mm were incorporated at 0%, 0.25%, 0.50%, 0.75% and 1.0%. Specimens were evaluated by compressive strength, slump, moisture absorption, rebound hammer and ultrasonic pulse velocity (UPV) tests. Compressive strength peaked at 26.08 N/mm² with 0.25% fibre, 25.0% above the control (20.86 N/mm²), and declined to 23.75 N/mm² at 1.0%, which remained 13.9% above the control. Slump rose from 150 mm to 162 mm at 0.25% fibre and fell to 102 mm at 1.0%. Moisture absorption increased steadily from 3.00% to 4.44%, and UPV decreased from 4.32 to 3.81 km/s, although all mixes were classified as good quality. Rebound hammer estimates followed the compressive-strength trend. Within the tested range, 0.25% fibre gave the most favourable combination of strength, workability and limited penalties in absorption and UPV. The results derive from a single series of mixes without replicate statistics, and mix proportions, testing age and long-term durability require further confirmation before practical application.

KEYWORDS: Agave americana fibre; fibre-reinforced concrete; concrete bricks; compressive strength; moisture absorption; non-destructive testing; sustainable construction materials