Effects of Concrete with the Implementation of Spent Coffee Grounds

During this study, compression tests were performed on three different concrete mix designs to evaluate the effects of spent coffee grounds as an admixture. The initial mix design was the control mix, composed of a general concrete mix design containing aggregate, cement, and water. The second mixture utilized was high strength concrete; this included aggregate, cement, and water, fly ash. The third mixture tested consisted of aggregate, cement, water, and spent coffee grounds. The purpose of evaluating these three different mixtures is to see whether spent coffee grounds can be implemented into concrete without compromising the compressive strength. Substituting 15% of the cement with spent coffee grounds would reduce the greenhouse gas and carbon footprint impact of cement and spent coffee grounds. These tests were comprised of a 7-day, 14-day, and 28-day cure in a controlled environment. The results of the tests showed that the implementation of spent coffee grounds in concrete would not be a suitable admixture, displaying a significant decrease in compressive strength. Due to human error, there was an absence of considering the water to cement ratio and it was not adjusted implying that there may need to be further testing to accurately evaluate the effects of spent coffee ground.