Aggregate Grading Analysis Using the Bailey Method of Gradation Selection

In the design of I-lot Mix Asphalt (I IMA) the aggregate gradation is one of the important
factors that have to be considered in pavement design and ultimately, in the
constriction, because it accounts for the overall strength of asphalt in terns of resisting
pennanent deformation such as pitting. The pui-hosc of' this project is to implement the
aggregate gradation analysis to a mix, which follows the standard of Malaysia in
accordance with the Jabatan Keija Raya (JKR) standard specification for road works of
Malaysia, using the Bailey method of gradation which follows a design and analysis
procedure that includes an examination of aggregate packing and aggregate interlock,
blending aggregates by volume, a new understanding of coarse and fine aggregate, and
analysis of the resulting gradation.
'l'he idea was to analyze and compare, based on the Marshall Mix design factors and the
I lamburg \Vhcel track test, a hot-mix asphalt (I IMA) constructed using aggregates with
it gradation limit that is in accordance with JKR and an I IMA constructed using
aggregates that are optimized by the Bailey method which uses aggregate packing
concepts to analyze the combined gradation and relate the packing characteristics to the
mixture volumetric properties and compaction characteristics. During the course of the
research, the findings gave us a basis in which to analyze whether this method can he
adopted and also if it will he useful and/or beneficial to the Malaysian pavement design
industry.
What the lindings yielded was that the I IMA designed following the JKR standards i. e.
ACVV 20 wearing course, according to the bailey method, is as follows:
- The mix yaS SusceptibIC to segregation
- Has a possibility of tenderizing
- May be difficult to compact
So the bailey method was able to yield it new and better performing HMA blend.