Enhancing concrete strength and sustainability: the role of Medan Barangan banana skin powder as a cement substitute

Cement is commonly utilized as a binding agent in the construction industry, making it the most essential component in concrete production. Globally, cement production contributes to 8% to 10% of anthropogenic carbon dioxide (CO2) emissions. With the rapid expansion of the cement sector, CO2 emissions are expected to rise. Therefore, reducing cement consumption is crucial to mitigate global warming. This study employed experimental research conducted in a laboratory (Civil Engineering Laboratory, Universitas Medan Area, Indonesia), creating 60 cylindrical and cubic test specimens. It investigates how agricultural waste can yield innovative, sustainable, and eco-friendly concrete, thereby decreasing environmental issues and CO2 emissions. Agricultural waste contains pozzolanic materials that, when finely ground, initiate a pozzolanic reaction where calcium oxide (CaO) and silica combine to form calcium silicate, enhancing concrete's strength. In this research, banana skin powder (BSP) from Medan Barangan, a by-product of agriculture, was tested as a substitute for cement in 2.5%, 5%, and 7.5% variations. The high silica content in Medan Barangan BSP is likely to induce a pozzolanic reaction in the concrete mix, thus improving the concrete's strength. The results indicated that a 2.5% substitution of Medan Barangan BSP increased the concrete's compressive strength but decreased at 5% and 7.5% substitutions. Therefore, the concrete mix can feasibly include Medan Barangan BSP waste. These findings are particularly beneficial to the community, especially in Medan, for application in the construction sector. However, it is advised to limit the substitution to no more than 5% of the total cement weight.