Piles of material suspected to be B3 waste (hazardous and toxic material) were found in Kemloko Hamlet, Jotangan Village, Mojosari District, Mojokerto Regency. The pile of material suspected to be waste from coal with the type of bottom ash and fly ash was discovered first by Gangsar Aji Santoso, Friday (05/31/2019). Gangsar added, the effect that may occur if people exposed by bottom ash is that they will experience itching on the skin. If rain comes and the water absorbs the material, it will pollute the flow of water around and can not be consumed (jatimnow.com, 2019).
Concerned with these environmental problems, Peliteknik Negeri Semarang PKM Research Team, leaded by Havilah Probahapsara, with his members, Gana Sasena Aji P S and Aqil Alifian, students of the S.Tr Study Program - Building Maintenance and Repair Engineering, Department of Civil Engineering and Drs. Sutarno, MM. as the advisor lecturer succeeded in developing concrete without cement with a polymerization method from coal waste basic material in the form of fly ash from the Tanjung Jati PLTU that was reacted with alkaline and bottom ash as a substitute for sand.
From the results of this research, the composition of the geopolymer concrete mix is able to approach the minimum quality of conventional concrete, K100 quality, so that it can be used as a non-structural building material, in addition from the results of the B3 waste content test, it is found that the concrete that is produced has a heavy metal content of Cd, Cr , Pb and Zn below the quality standard stipulated by Government Regulation of the Republic of Indonesia No. 101 of 2014. This research is expected to be able to overcome the coal waste produced by the PLTU as an alternative material for building concrete in order to realize sustainable development and of course produced environmentally friendly concrete products that has high quality, inexpensive and safe to use as building construction materials.