Field and Laboratory Investigation of the Influence of Fine Aggregate Angularity on Rutting of Flexible Pavement

Abstract

The primary purpose of this study is to identify the causes of rutting in highway pavements in the form of channelization particularly on wheel tracks resulting from high traffic repetitions and environmental effects. The rutting reduces the required performance due to poor hot mix asphalt (HMA) components and construction to mention a few. The study focused on the impact of fine aggregate angularity (FAA) to increase Asphalt layer stability. AASHTO testing method (T 304) was applied at the expense of uncompacted void content as a measure to determine the fine aggregate angularity index. Through the selection of samples of fine aggregate natural and crushed used in the production of hot mixt asphalt in Khartoum State by adopting Asphalt Institute requirements as described in Superpave design method, in Relation between Angularity and Traffic volume (ESAL) . This study applied Marshall Design method in the evaluation of properties of asphalt mixture voids, stability and other indicators to assess the results in producing accepted mixture with good performance. The study also included data collection on producing crushed aggregate, quarry sources and suitability for hot mix asphalt within Khartoum state to study the cause of rutting in the Ring road and Elsteen Street as case study in order to link the angularity and texture with the both process of crushing aggregate and various type crushers available. Data analysis has shown the high FAA value increase the stability. For the proper matching between all mixes properties, the mix should not be design to optimize one particular property mixes. Also the finding from this study indicate that regarding the existing HMA in the Ring road the fine aggregate angularity with blended natural and crushed aggregate is suitable for the current ESAL according to Asphalt Institute requirements.