Fibre mastic asphalt

Fibre Mastic Asphalt (FMA) is a technology that utilizes a specific aggregate gradation and matrix for high stability. FMA is used to hold the aggregate matrix in place while providing extended durability. This formulation would be able to handle heavy loading from commercial trucks and thus minimizing pavement surface distress. Some of the major applications of this technology would be at high loading or areas with intensive traffic frequency such as ports and expressways. It uses a binder which is a cellulose fibre in the formulation of the fibre mastic. These primary binders are found to give better performance in terms of stability and drain down capability of the asphalt mix.

FMA is a gap-graded mix with a high coarse aggregate (stone) content of 70–80 %, binder (asphalt) content of 6 % and filler (limestone sand) content of around 7–11 %. The percentage of cellulose fibre that is required for the FMA is 0.4 % and air voids of around 4 %. The skeletal formation of the coarse aggregate provides high resistance to deformation. Adding the fibres to the binder will prevent the asphalt from draining off during storage, transport and paving. The mastic fills the voids and retaining the aggregate in place. It has an additional stabilising effect, as well as providing the designed air voids. The result is a highly durable rut resistant asphalt mix. FMA can be used on all types of road and it is suitable for roads with heavy traffic loads and frequency. It is high binder content gives a longer lifetime than conventional mixes. Furthermore, it allows for the bitumen to bulk or thicken in order to prevent it from running off the aggregate before compaction. Its coarse and open texture generally provides high skid resistance at all speeds, as well as good drainage and fewer spray problems. Modification and stabilization of the asphalt binder is the approach to improve the pavement performance especially for the gap-graded mixtures such as FMA, which required higher viscosity asphalt binder. The method for this asphalt binder modification is by adding cellulose fibre and other oil- based materials are being used to enhance the viscosity of the base binder.

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