Abstract:
Hot mix asphalt mix design is the process of determining appropriate proportion of the
materials that would give long lasting performance paving mixture during its service life.
HMA is a mixture of mineral aggregate, binder and air indifferent relative proportions.It
is well recognized that the properties of hot-mix asphalt /HMA/ mixture depends up on
its different constituent materials. Among which, mineral fillers are one of the constituent
element which play an important role on the properties hot-mix asphalt. So, better
understanding of the effects of fillers on the properties of HMA mixtures is crucial to
good mix design and high performance of HMA mixtures. This paper presents a
comparative laboratory investigation into the effects of partially replacing conventional
filler /crushed stone dust/ by bagasse ash and groundnut shell ash on some properties of
HMA mixtures. A number of trial mixes/120/ have been prepared by the Marshal Mix
design procedure using three different percentage of crushed stone dust filler/5%,5.5%
and 6%/and five varying bitumen contents 4-6% at 0.5% increment to determine the
optimum filler and bitumen contents from which the design bitumen/filler content was
selected which was later utilized while crushed stone dust was partially replaced by
bagasse ash /at 0,5,10,15,20,25and100%/ and groundnut shell ash/at 0,5,10,15and100%/
all passing No. 200 sieve/0.075mm/ as a filler to determine optimum replacement percent
and their effect on hot-mix asphalt properties. The properties of HMA mixtures evaluated
include indirect tensile /ITS/ strength, tensile strength ratio /TSR/, marshal and
volumetric properties. The results obtained shows that, crushed stone dust, GSA and
SCBA mixes exhibit satisfactory trend result with a design bitumen content of 5.248%.
However, partial replacement of crushed stone dust with bagasse ash and groundnut
shell ash as filler in hot mix asphalt has no significant effect on performance, or
volumetric properties of asphalt concrete except on tensile property, Va content, stability
and flow at 10% and 15% replacement percentage of GSA and SCBA satisfying the
allowed range of control specification requirement. Having this into consideration, in this
research it is found that the optimum replacement percentage of GSA and SCBA as a
filler is 10% and 15% respectively.
