Performance Evaluation of Solanum Incanum Juice as aSustainable Bio-Admixture for Concrete

Abstract

Cement production harms the environment and often relies on chemically produced admixtures imported from developing countries like Ethiopia. This reliance has encouraged efforts to find alternatives to conventional cement and concrete technologies. The use of Solanum incanum (əməbʷay juice (EJ)) is a potential additive to Portland cement. EJ contains compounds that demonstrate similar properties to currently produced water-reducing and retarding chemical admixtures. A C25/30 mix was created according to ACI 211.4R-08 and was treated with EJ at percentages of 0.5%, 1%, 1.5%, 2%, 3%, 4%, and 5% of the weight of the cement. Both the partial water replacement and additive methods were used. The fresh properties of the concretes were tested according to ASTM C143 for slump, ASTM C191 for setting time, and the hardened properties were tested according to BS EN 12390-3 for compressive strength. Samples of 150 mm cubes were cured for 3, 7, 14, and 28 days before testing. The physicochemical analysis of EJ indicated a pH of 4.2. The main components of EJ were found to consist of % of fatty acids, which ranged from 26.64% to 50.41% (on a dry basis). This crude EJ significantly enhanced the workability of concrete, up to 863.6% increase in slump value at 5% dosage by weight of cement. The effect of EJ on the cement showed retarding effect on the setting of cement. The results of this study also indicated that higher dosages (3%–5%) of EJ accelerate the setting time of cement by up to 57.14% than that of control sample. Based on the experimental results, the work identified the optimal percentage of EJ to be used as a bio-admixture for concrete under partial water replacement conditions. The result indicated that 2% of EJ yielded a 28-day compressive strength of 28.6 MPa, which corresponded to an increase of 3.36% over that of the reference specimen (M40 mix) and was almost comparable to that of Sika Plastiment BV40 (commercial admixture). Higher dosages (3%–5%) of EJ caused a decrease in the strength of concrete and even led to the disintegration of specimens. In the long-term perspective, the study revealed that the use of EJ is a more economically viable option than the usage of imported admixtures for a period of ten years within the Ethiopian market. The findings revealed that EJ has great potential as a sustainable, cost-effective, and locally available bio-admixture for use in concrete.

Keywords: Bioadmixture, Solanum incanum, ʾəməbʷay juice, Sustainable concrete, Workability, Setting time, Compressive strength