In Kenya there has been high occurrence of asphalt pavement failure sometime after the construction. This begs the question, what causes the pavement failure? This question implies that there are changes in stressstrain relations of asphalt materials when exposed to traffic loading and climatic conditions more so the high temperature causes the pavement to fail. These changes in stress-strain characteristics causes changes in the strength properties of asphalt thus causing the asphalt mixture to perform poorly as a paving material. With greater truck carrying capacity in Kenya, trucks are imposing more stresses on Kenya's flexible pavements, resulting in elastic deformation of the pavement through bulging and cracking. Larger truck loads will undoubtedly have a negative influence on current pavements, necessitating further investigation into the possibility of revamping the pavement with better material. Larger loads cause the pavement to crack and disintegrate. The road surface is distorted by this bulging, also known as road shoving. Because the road gradient is twisted, the surface water on the pavement no longer drains to the roadside ditches. Water on the surface will most likely cause potholes because it seeps through tiny fractures, causing pore water pressure to build up, ripping the asphalt substance apart. Water trapped between the bulges will gradually lead to the creation of more potholes in the pavement, which will eventually lead to full pavement failure. The problem of road shove and corrugations forces the government to set aside significant maintenance and repair costs, making the project costly. Truck owners have decided to invest in large carrying capacity, which entails higher axle load limitations, due to transportation economics. This indicates that tire pressures have risen over time, resulting in increased pressure exerted on the flexible pavement, resulting in elastic deformations. As a result, increased stresses on asphalt materials are unavoidable, and engineers must develop asphalt material combinations that can sustain high pressures. Asphalt mixtures are made up of a combination of bitumen and aggregates. Because bitumen components are temperature sensitive, they breakdown in hotter climates like Kenya, resulting in pavement deformation in the form of road shove. This means that the asphalt strength qualities must be changed to create a safe bearing capacity that matches the increased weight limitations
BSC CIVIL ENGINEERING
Eng. Miracle Wachira
Achoki Brian Orango. F16/101182/2017.