The effect of limestone and reheating temperature on cold paving hot mix asphalt

The objective of the study is to evaluate the effect of the limestone proportion and reheating temperature to the Marshall characteristics of the cold paving hot mix asphalt (CPHMA) using a natural asphalt from Buton, Indonesia. The mix is prepared and mixed in hot temperature like hot mix asphalt, but laid and compacted at normal temperature. The normal application of this mix is for patchwork, due to its lower performance. In order to upgrade its performance, the research attempts to add limestone material and reheat the mix before laying and compacting. As many as 60 Marshall specimens were prepared with varied asphalt content, percentage of limestone, and reheating temperatures. The specimen were prepared in two stages: mixing process and compaction process. The mixing process was performed like regular hot mix asphalt. After the mixing, the specimens were placed in a batch for 24 hours. The mixes were then placed in the Marshall tube to prepare the Marshall specimens, compacted, and tested. The results showed that heating the mix to about 42oC significantly improves the mix performance, particularly on its Marshall stability. The existence of limestone in the mix also improved its performance. Based on the results it can be concluded that given some treatments, the CPHMA can be used not only as patching material but also as structural layer material, particularly for low to medium traffic rural road.