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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/1483

Title: Effect of Different Types of Filler Materials on Characteristics of Hot-Mix- Asphalt Concrete
Advisors: Dr. – Ing. Girma Berhanu
Copyright: 2007
Date Added: 18-Oct-2008
Publisher: Addis Ababa University
Abstract: 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 types of mineral fillers in hot-mix-asphalt performance. The mineral fillers, with different percentages by total weight of the mixture, used in the study were crushed stone, volcanic-cinder, and limestone passing 0.075mm sieve. Using the different types and contents 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 type 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. Using the different mineral fillers at their respective optimum asphalt content, specimens were prepared to investigate moisture susceptibility of asphalt mixtures. The Marshal Immersion test method was adopted to determine the moisture effect of mixtures. The test results show that all mineral fillers do have an effect on various mixture properties. Mixtures prepared with volcanic-cinder require higher asphalt content to fulfill all the Marshal requirements. This makes these mixtures more costly from practical point of view. Higher stability values were however, obtained by mixes with volcanic-cinder as compared to limestone and crushed stone fillers. Moreover, higher retained stability values are obtained by mixes prepared with limestone and volcanic–cinder as compared to the widely used crushed stone. The dynamic moduli values, estimated using the formula developed by the Asphalt Institute, were higher for mixtures prepared with limestone fillers and crushed stone as compared to volcanic-cinder at higher filler contents starting from 5% in the mixture. x From the study, similar trend of mixture properties, particularly Marshal properties, were observed for mixes made with limestone and crushed stone fillers as compared to that of volcanic-cinder. This indicates that limestone can be used as a substitute for the widely used crushed stone where available. This, of course, requires further investigation that better simulates the field condition. On the other hand, inconsistent mixture properties were observed from mixes made with volcanic-cinder. This also entails further investigation if it is deemed to be used as filler materials in asphalt concrete. Generally, different characteristics of bituminous mixtures were observed by varying the fillers in the mixture by type and 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.
Description: A thesis submitted to School of Graduate Studies of Addis Ababa University in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering (Road and Transport Engineering)
URI: http://hdl.handle.net/123456789/1483
Appears in:Thesis - Civil Engineering

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