The Evaluation of Asphalt Mix Design in Order to Extend the Service Life in Asphalt Pavement
Pavement permanent deformation is a major distress in South African (SA) flexible roads. Pavement permanent deformation refers to the change in shape of a solid pavement due to stress and strain without the pavement changing back to its original form. Permanently deformed surfaces form a rut which is referred to as a permanent depression into a road as a result of deformation of the asphalt pavement or subbase material. Rutting might lead to the bigger structural failures in the pavements. Every load applied on the surface cause permanent deformation which leads to rutting.
The failure of asphaltic pavement to carry traffic loading without rutting is a major problem on Butterworth roads in the Eastern. Fatigue failure has been a huge problem in many roads in SA by not meeting the design service level. Aged binder also has a huge significance in the distress of asphalt mixtures. The stiffness of asphalt mix increases due to stiff or less elasticity in binder. This will result in fatigue damage and brittleness of the asphalt pavement in low temperatures.
The main aim of this study is evaluate the asphalt mix design in order to extend the service life of asphalt pavement. The study is limited in the evaluation of asphalt mixture design and its effect on asphalt mixes by means of laboratory tests only.
The methodology adapted to meet the objectives of this study implicated a field investigation and laboratory investigation. All the tests were carried using Testing methods - TMH1. The laboratory investigation was conducted to characterize permanent deformation property of asphalt mixtures by means of grading of aggregates, determination of suitable binder content, determination of resistance to flow and voids analysis by Marshall method and bulk relative density of the briquettes.
The study has discovered that rubberize asphalt has a higher resists to deformation. This is due to the characteristics of the rubber crumb binder which enables the HMA to resist fatigue on the road thus extends the road service life and performs well under extreme heavy traffic load.
Previous research states that the shear resistance of fine aggregate has a vital role on the mixture resistance (Verhaeghe et al, 2011)
Keywords - Deformation, Asphalt, Rutting, Hot Mix Asphalt (HMA)