A group of students from the Ten November Institute of Technology (ITS) in Surabaya, East Java, has discovered ways to produce self-compacting concrete using waste from palm oil production, a report quoted by the Indonesian Association of Palm Oil Producers (GAPKI) said on Friday (14/12).
The WcFlurry Group that comprises three students — Cita Nanda Kusuma Negari, Agus Bastian and David Gideon— used palm oil fuel ash (POFA) in the making of the cement. POFA has so far become problematic for the palm oil industry because of its large quantity and the need for an increasingly wider plot to dump them, GAPKI said in a report it carried in its official webpage.
“So, we wanted to come out with a sustainable concept from those points,” said Negari, a student from the university’s civil work department.
The POFA which is used as a substitute to cement has to be first passed through a sieve and have to pass sieve number 325 to obtain the right particle size. POFA contains pozzolan that is high in silica, alumina, and iron, which together contribute to triggering a secondary hydration reaction which would increase the strength of the concrete. “If the size of the particle is bigger than that of cement particles, the POFA would only act as filler, not as a binder,” Negarti said.
The resulting cement has a high fluidity level and would not need to be compacted first with a compactor. “The Pozzolan content exceeds 70 percent and therefore it is already in line with the Indonesian National Standards 9SNI),” she added.
In its project, the group was mentored by Faimun and Professor Tavio and the concrete has already gone through a slump flow test, an L-Box and compressive strength tests. The two first test is to define the workability of the concrete mixture. The tests yielded a value of 685 millimeters, thereby meeting the standards of the European Federation of Specialists Construction Chemicals and Concrete Syst3ems (EFNARC).
The compressive strength test is to determine the limit of compression the concrete can stand and yield an average value of 26 megapascals. The concrete has already won the third price in the international Concrete Competition (ICC) 2018held at the Eleventh of March University (UNS) in Solo, Central Java, recently.