Evaluation of the Hot Asphalt Mix Aggregate Gradation Using Bailey Method: A State-of-the-Art

Abstract

The selection of the aggregate gradation, in the process of the asphalt mix design, is one of the most critical steps because it accounts for the overall strength of the asphalt mixture in terms of resisting the permanent deformation or rutting. This paper focuses on evaluating the current aggregate gradation selection procedure for the hot asphalt mix (HAM) using the three Bailey ratios. Additionally, this study analyzes, theoretically, the compaction and performance characteristics of the resulting HAM designed using the traditional design procedures which follow the trial-and-error technique in order to have a mix that satisfies the specification range. Results show that 14% of the samples prepared using the traditional technique satisfy the Bailey method guidelines and thus indicate good performance in the field. However, almost 80% of the asphalt mixes are tender asphalt mixes that are prone to segregation in the field, and 6 to 7% of the asphalt mixes are hard to compact. Based on the findings of this research, it is recommended that the Bailey Method analysis process should be incorporated into the mix design process as an additional tool to develop and select trial blends for the design of the asphalt mixes in Egypt.