Influence of polyester fibre on the performance of Asphalt mixes

Abstract

Paper presented at the 26th Annual Southern African Transport Conference 9 - 12 July 2007 "The challenges of implementing policy?", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT:In order to determine the influence of polyester fibre on the performance of asphalt mixes, two types of polyester fibre were selected. One is locally made and the other is imported. Using the wheel tracking test device, the Marshall test device and the material test system (MTS), the high-temperature stability, water stability, low-temperature crack resistance and fatigue resistance of asphalt mixes with the same gradation were studied by means of comparative tests, in which one mix had added polyester fibres and the other mix did not. The results showed that polyester fibres do improve the performance of the asphalt mix. Polyester fibres are able to improve the high-temperature stability, mainly due to their stabilising and multi-directional reinforcing function. They also absorb the bitumen and thicken the bitumen film adhering to the aggregate, which strengthens the resistance of the asphalt mix to environmental disruption and water damage. Polyester fibres remain flexible at low temperatures. By interlacing vertically and horizontally, the fibres increase the elasticity of the asphalt mix and prevent cracks from developing and propagating in the mix at low temperature. Therefore, polyester fibres can improve the low-temperature performance of asphalt mixes significantly. As a result of their three-dimensional random distribution, the polyester fibres are able to block the propagation of cracks, increase the elastic recoverability and delay the loss of material stability and the appearance of rupture, which improves the fatigue resistance of the asphalt mix. Because the polyester fibres could improve the field performance of asphalt mixes comprehensively, they will be of great benefit to the engineering field.