ANALYSIS OF MARSHALL CHARACTERISTICS WITH FLY ASH MATERIAL FOR STONE DUST SUBSTITUTION AS FILLER IN HRS-WC MIXTURE

Abstract

Lataston asphalt mix is a thin layer of asphalt concrete that is often used on light-traffic roads because it produces roads with good flexibility and durability. An economical way of doing this is to vary the asphalt mix, especially by modifying fillers, to improve the quality of the road pavement and asphalt mix. So, an alternative was found, namely the use of fly ash, residue from the Asam-Asam PLTU. The filler material for fly ash which will be varied with the filler for stone dust, plays a role in filling the voids between aggregate grains in the Hot Rolled Sheet-Wearing Course (HRS-WC) mixture with each predetermined composition. This study aims to determine the characteristics of the HRS-WC asphalt mixture with respect to the utilization rate of rock dust and fly ash fillers. To find out the characteristics of a HRS-WC mixture with mixed variations of the two fillers, the method that will be used is the Marshall Test by analyzing each characteristic of the parameters to be obtained in accordance with the 2018 Revised Highways Specifications II Year 2018 to make the mixture hot asphalt. The bitumen content used in this study was 4.5%, 5.0%, 5.5%, 6.0%, and 6.5%, with varying levels of fly ash and rock dust filler, namely 100%: 0%, 80%: 20%, 50%: 50%, 20%: 80%, and 0%: 100%. The results of the Marshall characteristic calculation analysis show that the asphalt mixture with lataston is very influential in the substitution of rock ash as a fly ash filler. Lataston asphalt mixture tends to be stiff and easily cracked because it has a high stability value of 1,615.38 kg and the lowest flow value of 4.10% in the 100% fly ash filler variation. At optimal asphalt content, the HRS-WC asphalt mixture for each variation in the range of fly ash and rock dust produces a decreased asphalt content because the water absorption capacity of rock dust is less than that of fly ash filler, so less asphalt is needed. In addition, the HRS-WC asphalt mixture also shows increasing durability, along with the replacement of rock dust filler with fly ash filler, which can be seen from the increased stability values, MQ values, and VFB values.