Browsing by Author "Gonza Edgar"

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    Assessing the Use of Calcined Quartzite Dust as a Filler to Enhance Rut Resistance in Asphalt Concrete
    (Uganda Christian University, 2025-04-16) Gonza Edgar
    Road construction is a crucial aspect in infrastructure development and choosing the right materials for road ways can significantly impact their durability, maintenance requirements and overall performance. The two most common materials in road construction are concrete and asphalt concrete. Asphalt concrete, which is widely used for road and highway construction and consists of bitumen aggregate and a mineral filler combined through a hot mix process prior to laying on the roadway. Its flexible and has excellent water proofing and adhesive properties. to improve on asphalt concrete performance, researchers have been working to create more sustainable asphalt concrete pavements over the years with several attempts to modify the binder or filler materials of asphalt such as incorporating fly ash or plastic waste in the bitumen and using fillers such as lime stone dust. This study aims at ascertaining whether calcined quartzite dust can be used as an additive in asphalt concrete to enhance rutting resistance. The road sections along climbing lanes are subjected to slow heavy moving traffic and repeated heavy loading under high temperatures that reduce its ability to resist shear stresses that result into the formation of ruts. Ruts are the permanent deformation along the wheel part in asphalt concrete layer due to softening of the binder under high temperatures and heavy loads. A case study on the Bweyogerere stretch climbing lane along the jinja Kampala highway despite previous renovations has revealed premature deterioration in the form of instability rutting in the asphalt concrete layer. Aggregates and bitumen, using mechanistic and empirical approaches were assessed in order to understand such failure. While the aggregate performance was found to be good, the susceptibility of bitumen to temperature variations resulted in reduced stiffness at high temperatures. Introduction of calcined quartzite dust as filler has the potential to improve the thermal stability and load distribution of asphalt mixtures, with consequent improvements in stiffness modulus and rut resistance to permanent deformation without compromising durability.