Workability and Compressive Strength Development of Banana Leaf Ash Based Concrete

Abstract

Objective: To evaluate the effect of banana leaf ash (BLA), used as a partial replacement for ordinary Portland cement at 0-30% by weight in 5% increments, on the workability and compressive strength of concrete at 1, 3, 7 and 28 days of curing, and to identify a practical BLA replacement level for low-strength construction applications.

Research Method: Dry banana leaves collected from the Nawabshah area of Sindh were burnt and sieved to produce BLA. Standard 100 x 100 x 100 mm concrete cubes were cast at seven BLA dosage levels (0%, 5%, 10%, 15%, 20%, 25% and 30% by weight of binder), with mix proportions, aggregates and the water-binder ratio held constant across all batches. Slump was measured immediately after mixing, and compressive strength was determined using a universal testing machine after 1, 3, 7 and 28 days of water curing.

Findings: Both workability and compressive strength decreased consistently as BLA content increased. Slump fell from 49 mm (control) to 7 mm at 30% BLA, an 86% reduction, with the rate of loss accelerating sharply beyond 15% BLA. Twenty-eight-day compressive strength fell from 29.9 MPa (control) to 14.5 MPa at 30% BLA (a 51.5% reduction), while at 10% BLA the 28-day strength loss was limited to about 9%. These trends are consistent with recent BLA studies (Islam et al., 2024; Aanu et al., 2025) that likewise report a dilution-driven strength penalty at comparable dosages.

Originality: While fly ash, rice husk ash and sugarcane bagasse ash are well characterised as cement replacements, banana leaf ash remains comparatively under-studied. This is among the first investigations to evaluate BLA concrete across a full 0-30% dosage range at four curing ages using locally sourced agricultural waste from Sindh, Pakistan, providing a regionally grounded dataset in support of agro-waste valorisation in construction.