Optimization of fly ash and bottom ash substitution against paving block manufacture according to SNI 03-0691-1996

Abstract

The waste of coal burning has a very negative impact on the environment if the waste is not managed as well as possible. The remaining waste of coal combustion consists of fly ash and bottom ash. FA and BA can be developed into substitution materials in the process of making paving blocks. The purpose of this study was to determine the quality of paving block in accordance with SK SNI 03-0691-1996 with optimization in the use of FA and BA. This study uses a 351 paving block sample size of 20x10x6 cm. Paving blocks are divided by 4 categories, namely normal paving block, paving block with FA substitution, BA substitution and combination of FA-BA with each variation 0%, 25%, 50%, 75% and 100%. Each variation amounted to 27 samples. Paving block quality measurement is done through 4 tests: absorption, compressive strength, sodium sulphate resistance and Los Angeles tests. The result of the test shows the absorption of normal paving block is 3,229%, paving block with 25% FA is 3,889%, paving block with 50% BA is 5,560% and paving block with 25% FA-BA combination is 5,794%. Compressive strength in normal paving block is 25,50 MPa, paving block with 25% FA is 25,28 MPa, paving block with 25% BA is equal to 27,61 MPa and paving block with 25% FA-BA is 26, 00 MPa. In testing of sodium sulfate resistance, almost all test specimens are eligible except for paving block with 50% FA and 75% FA. In the test of wear resistance, no specimen is eligible according to SK SNI 03-0691-1996. The comparison of the strength of the test specimen can be seen in substitution with 25% BA which reaches maximum strength.