Analysis of fly ash from PLTU Asam-Asam as a construction material in terms of its physical and mechanical properties

Abstract

Nowadays, PLTU Asam-Asam produced enormous amounts of combustion waste in the form of coal ash. On the contrary, only a little effort has been made to utilize coal ash from PLTU Asam-Asam, especially from the research side. In fact, due to its siliceous material, when reacting with CH in concrete, will form CSH hence improves concrete strength. In this study, in order to analyze the physical and mechanical properties of concrete using fly ash from PLTU Asam-Asam, 54 concrete samples were prepared according to SNI-03-2834-2000. The examination of concrete samples workability was conducted based on the slump test according to SNI 1972:2008. Moreover, the compressive tests were carried out in accordance with SNI 1974:2011. The slump test results show that the pozzolanic reaction of fly ash contributes to the improvement of concrete workability. Furthermore, the variation in w/b ratio was also affecting the results of the slump test. As for the compressive strength, in general speaking, the replacement ratio of 30% of cement with fly ash in concrete could produce concrete strength up to 30 Mpa. It is also important to note that due to the pozzolanic reactions tends to delayed, it is expected that at later ages (above 28 days) concrete with fly ash will gain much more strength compared to ordinary concrete.