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Various studies have shown that the properties of mineral fillers have significant effect on the performance of asphalt concrete pavements. This study was intended to investigate the effect of different content of mineral fillers in hot-mix-asphalt performance. The mineral fillers, with different percentages by total volume of the mixture, used in the study were crushed stone, and diatomaceous earth passing 0.075mm sieve. Using the different content of the mineral fillers, a number of trial mixes have been prepared using the Marshal Mix design procedure to arrive at asphalt concrete mixtures that fulfill the Marshal criteria. The effects of each mineral filler content on Marshal Properties of the asphalt mixtures at their respective optimum asphalt content were evaluated and possible basis for such difference in properties was discussed. Generally, different characteristics of bituminous mixtures were observed by varying the fillers in the mixture by content. This indicates that, mineral fillers are recognized as an important ingredient in the mixture property. From the test results obtained, there is a common trend in obtaining different mixture properties with varying filler content, which shows, there exists optimum filler content that best mix performance could be achieved. The results of this research work is hoped to be used as the basis for further investigation on the effects of mineral fillers and improve asphalt concrete mixtures as well as find alternative materials.
The results of this study indicate that the range fulfills all the design requirements at 3%5% diatomaceous earth filler content. This implies that diatomaceous earth which has being used as a filler material in hot mix asphalt has a good performance in the construction of bituminous pavements in Ethiopia. Therefore, overlooking of the test result of diatomaceous earth it has a good Marshall test result as the traditional filler material which indicates it can be used as a substitute filler material in Asphalt paving. Considering their cost AC prepared by the diatomaceous earth and filler materials have less cost than the traditional filler (crushed stone dust). But comparing the two filler types diatomaceous earth have a lower cost of construction than crushed stone dust at 5% of filler content. Therefore, this research work is hoped to be used as a basis for future studies about different types of mineral fillers in provision of strong durable bituminous pavements from industrial waste materials. |
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