Evaluation of compactive effort and time available for compaction on hot mix asphalt

Abstract

The objective of this study was to determine the effect of compaction effort on marshall properties of two types of mix design which is from asphaltic concrete (AC) and bituminous Macadam (BM). The types of mix design are AC14 and BMW20 which is for Hot Mix Asphalt (HMA). This study also determined the time available for compaction for AC14 and BMW20. Compaction is one of the important factor in constructing a pavement. According to JKR specification, the number of blow is 75 per face. For this study, the number of blow used were 35, 50 and 75. Bitumen content that has to be used for asphaltic concrete is between 4 to 6 percent. Compaction, flow and stability test for AC14 were carried out to determine the optimum bitumen content for each blow. The result of OBC for 35 blow was 5.54%, 5.32% for 50 blow and 5.23% for 75 blow. The results show that the increase of the number of blow would decrease the optimum bitumen content. After comparing the parameter, the result for AC14 show that 35 blow and 50 blow of compaction do not meet the specification except for 75 blow. For BMW20, the bitumen content used was 4.9% for each blow. The results for BMW20 show that for each blow which is 35 blow, 50 blow and 75 blow comply to the specification. On the other hand, the time available for compaction of AC14 is 108 minutes and the time available for compaction of BMW20 is 100 minutes.