The utilisation of palm kernel shell as partial coarse aggregate replacement in asphalt mixture for heavy traffic flow

Using Palm Kernel Shells (PKS) in road construction has a promising potential to minimise the agricultural waste that causes environmental problems and reduce overall road construction costs. This study uses varying percentages of 10, 20 and 30% PKS, an agricultural waste material, as a coarse aggregate replacement mixed with a 60/70 penetration grade bitumen. The sample compaction is 75 blows using the Marshall Method to simulate heavy traffic flow. This research evaluates the fatigue and rutting performances of the modified asphalt mixture through resilient modulus tests to determine the pavement performance in unaged, short-term and long-term aged conditions. The results revealed that the unaged PKS-10 has a 35% lower resilient modulus than PKS-O after being subjected to varying pulse repetitions. The resilient modulus of the asphalt mixtures with higher PKS contents, PKS-20 and PKS-30, is about 55 and 65% lower than the PKS-O. The lower resilient modulus of all PKS asphalt mixtures indicates that PKS replacement is unsuitable for higher traffic volumes since it does not improve fatigue and rutting at intermediate and higher temperatures when subjected to ageing and different pulse repetitions. However, the lower ageing index than the control sample indicates that replacement with PKS delayed the ageing of the asphalt mixture exposed to heavy traffic flow and could extend the pavement service life.