THE INFLUENCE OF COMPACTION METHODS ON THE PROPERTIES OF HOLLOW CONCRETE BRICKS UTILIZING FLY ASH AND BOTTOM ASH

摘要

This study focuses on the maximal use of industrial waste from burning coal, i.e. fly ash and bottom ash, in making hollow concrete bricks (HCB). Fly ash (FA) and bottom ash (BA) obtained from East Java, Indonesia, is incorporated to partly replace the use of Portland cement and natural sand. The purposes of the study are to determine the appropriate mix proportion incorporating the maximal use of waste products and to evaluate the effectiveness of three compaction methods, i.e. Manual, Vibration with load and Static compaction. This study is part of an effort to produce environmentally friendly construction materials for sustainable development. The optimum composition of the mixtures was found to be the use of 31% FA of the total binder and 24% BA of the total filler, with the filler-to-binder ratio of 8.6 by mass. Among the three compaction methods studied, it was found that the maximum compressive strength of 66.9 kg/cm2 was achieved when applying the Vibration-with-load compaction method with 3 layers, 7 second vibration period and 40 kg block weight. This compressive strength satisfies the requirement for Grade II concrete brick in accordance to Indonesian National Standard SNI 03-0349-1989. The water absorption of HCB produced from all the mixes was found small, less than 15%, satisfies the requirement of maximum water absorption in accordance to the standard.