ITS students use waste to create concrete

(from the right) Tim Abhinaya S60: Cita Nanda Kusuma Negara, Kuntoro Tanoto, and Patricia Mayang Putri. (photo: IO/ITS)

IO, Surabaya – The increase in demand for concrete as the main material for building construction has not been balanced by the supply of cement, its main ingredient. Seeing this phenomenon, a team of students from Institut Teknologi Sepuluh Nopember (ITS) Surabaya has attempted to create a more economically-viable and environmentally-friendly concrete.

In trials, fly ash, better known as pulverized fuel ash (PFS) was chosen as a substitute for cement. According to a member of the team, Cita Nanda Kusuma Negari, fly ash is a residue left over from burning coal which contains various heavy metals and if not properly processed could harm the environment.

Besides that, the use of fly ash was able to decrease the cost of creating the concrete, while helping fight global warming. “When using normal Portland cement, the production process releases carbon dioxide which impacts on global warming,” she said.

Furthermore, she explained, substituting cement with fly ash also involved the use of rice husks and clamshell waste. Both these waste products were used as a mix in the creation of the concrete as they contained chemicals which could increase the concretes strength. “The main thing we are offering is recycling waste into material which has additional benefits,” said the second-year civil engineering student.

Fly ash, husk ash, and clamshell contain large amounts of silica and alumina. High silica content plays a role in secondary hydration reactions in concrete which can improve long-term concrete strength. “They can react for a long time and can increase the compressive and tensile strength of concrete.”

Cita admits that the results obtained by her team, named “Tim Abhinaya S60” needed hard work. In the process of making the concrete, her team went through a series of trials and errors to ensure the concrete was strong, one of which was a slump test. “This test was done to ensure the concrete mix stiffness in determining the concrete’s level of workability.”

With this innovation, Cita, together with Patricia Mayang Putri and Kuntoro Tanoto, hopes that the results could be useful in the construction industry. The advantage of concrete created by the team advised by Professor Tavio ST MT Ph.D. is good strength, environmental friendliness, and high quality. “Hopefully, our product will be able to address challenges in waste management while cutting back on cement consumption” she added.

Tim Abhinaya S60 has proven their excellence by placing first in the Warmadewa High Strength Concrete Competition in Universitas Warmadewa Bali last October. (ITS Public Relations)