Abstract:
This paper presents the utilization of coal fly ash in pavement construction that acts as
filler replacement which could improve the performance of its properties, particularly improving the
foundation of road bases, which would be also considering the seasonal effects such as frost. Frost
damage in cold regions is a phenomenon of great practical importance in highway engineering
design and construction. One of the objectives of this study is to investigate the effect of coal fly
ash (CFA) as a filler replacement on the mechanical properties of bitumen-aggregate mixtures at
various percentages 1%, 2%, 3%, 4%, 5% and 6% by weight of aggregate. Freeze and thaw cycle
test was conducted to simulate cold region countries condition, and compared with normal
condition. Marshall Test was done to evaluate the suitability of coal fly ash as mineral filler for
normal and frost conditions. Result obtained from test was compared between control sample and
sample with CFA. Marshall Parameters can be improved by adding CFA as filler replacement to the
HMA as compared to normal filler, although, results showed that by addition of CFA some
specifications of ST RK 1218-2003 «Materials on the basis of organic binders for road and airfield
construction. Test Methods» were not met requirements. It was observed that there was a definite
increase in Marshall stability and decrease in flow values. Optimum CFA was determined to be in
range of 1% to 3% by applying the range method. The mechanical properties, namely modulus of
resilient and tensile strength were determined by carrying out modulus test and indirect tensile test
respectively. The results revealed that the highest value of modulus of resilient for both conditions
when CFA content was 3%. Indirect tensile test conducted for frost condition only and found that
the highest value was in range of 2% to 3%.
