Asphalt breaking point

Breakings Point (FRAAS, IP 80/53). This test of the Institute of Petroleum is an approximate indication of the temperature at which an asphalt possesses no ductiUty and would reflect brittle fracture conditions. 

Rheology of SA Binders. Conventional test methods such as softening point, viscosity, penetration, Fraas break point, ductilities, etc. have been used to characterize the rheology of SA binders (11). The physical structure of SA binders is complex, and the sulfur-asphalt and sulfur-aggregate interaction make correlations to asphalt and to binder properties for aggregate rather difficult. 

Stability of the emulsion is of prime importance. If the emulsion breaks, the advantages of adding sulphur are completely lost, with the impact on strength and durability properties particularly detrimental. As sulphur in asphalt emulsions are unstable by nature, due attention has to be paid to this point. 

If an emulsion of this type is allowed to cool in the open air, it should be checked to see that no emulsion breaking occurs (the sulfur droplets remain separate) but that sulfur enrichment at the lowest points is discernible. This sedimentation only occurs when asphalt is relatively fluid, as a result of the substantial difference in density between sulfur and asphalt and where the total sulfur content is greater than 20%. 

The tank of the delivery vehicle should always be clean, before loading bituminous materials. Small proportions of foreign matter, usually petrol, diesel, oils and so on, directly influence bitumen s properties and, hence, the bituminous mixture and the quality of pavement. Furthermore, safety is affected since the presence of these substances may lower the flash point of the bitumen substantially. It has been found that 0.1% of diesel in bitumen can decrease the flash point up to 28°C and increase the bitumen penetration by 10 units (Asphalt Institute MS-4 2007). In case of transporting bitumen emulsions, the presence of foreign substances will certainly affect the breaking time of the emulsion. 

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