Assessment of Palm Kernel Shells as Partial Replacement of Coarse Aggregates in Highway Pavements

摘要

This paper looked at the potentials of partially replacing palm kernel shells with coarse aggregates in road binder course with emphasis on strength of the asphalt concrete as given by the Marshal Stability and flow values. The aim of the study was to assess the suitability of replacing coarse aggregates with palm kernel shells in highway pavements. The following methodology was adopted in the research, Specified proportions of each material such as 4% filler of size 0.075mm, 35% quarry stone dust of maximum size 5mm, 6% river sand of maximum size 5mm also and 20% crushed stone of size 5-16mm, 35% crushed stone of size 16-20 mm with 6% bitumen of penetration grade 60/70 was mixed together at 163. The mixture was compacted with 50 blows both at the top and bottom to obtain cylindrical samples for the Marshall Stability tests. Palm kernel shells were partially replaced at 0%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 100% by weight of total coarse aggregate in the mixture. The study found that palm kernel shells can be used to replace coarse aggregate up to 20% before drastic reductions become noticeable. It is therefore recommended that for heavily trafficked roads, palm kernel shells up to 10% can be used for the replacement while even above 70% replacement is possible for lightly trafficked roads in the rural settings.