Sustainable Concrete Enhancement Using Lemon Juice As A Bio-Admixture: A Comprehensive Study On Workability, Setting Time, And Compressive Strength

Abstract

Conventional chemical concrete admixtures contribute to environmental pollution, high energy consumption, and high import costs in developing nations. While plant-based alternatives are being explored, the potential of locally available lemon juice remains under-researched. This study experimentally evaluates the impact of lemon juice on concrete workability, setting time, and compressive strength, comparing its performance against a commercial water-reducer and retarder, Sika Plastiment BV40. Concrete samples with a target strength class of 25/30 MPa were created using the ACI mix design procedures and ASTM testing standards. Specified amounts of lemon juice were added at levels of 0.5%, 1%, 1.5%, 2%, 3%, and 5% by weight of cement, while some of the mixing water was replaced with lemon juice. It has been observed that testing the wet and hard states of the mixture is necessary for this study. Slump, Vicat setting time, and compressive strength tests were performed to determine how lemon juice affects the fresh and hardened features of concrete. Experts claim that the test results showed that lemon juice improved the workability of concrete. When the amount of lemon juice was 5%, the slump value increased by approximately 716.7% compared to the control mix. It was observed that 2% lemon juice increased the first setting time by 410 min. This delay was 57.7% more than the delay produced by the market chemical at the same amount. The best strength behavior was achieved when the lemon juice content was 1.5 %, where the 28-day compressive strength reached 29.11 MPa. This measurement was approximately 5.2% higher than that of the control concrete and was 0.9 MPa higher than the highest strength achieved by the market chemical. Because there was too much acid and more water, lemon juice amounts higher than 2% caused the strength to drop and the concrete quality to worsen. The study concludes that lemon juice has strong potential as a sustainable and eco-friendly bio-admixture capable of improving the fresh properties of concrete while maintaining or enhancing compressive strength at a lower dosage. The optimum dosage range was found to be between 1% and 1.5% by weight of cement. Further studies are recommended to investigate the long-term durability performance, microstructural characteristics, and large-scale practical applications of lemon juice in sustainable concrete technology.

Keywords: Bio-Admixture, Citric Acid, Compressive Strength, Concrete Workability, Lemon Juice, Retarding Admixture, Sustainable Concrete