Varieties of Viscosity Grade Bitumen and Their Applications
- weblognews1
- Oct 14, 2023
- 2 min read
Viscosity grade bitumen, often known as asphalt, stands as the most prevalent asphalt type in road construction and hot mix asphalt projects, featuring a suite of exceptional properties. Viscosity grade bitumen, denoted as VG bitumen, is the preferred choice for producing hot mix asphalt. Among the various viscosity grades available at Vira Petroleum, a leading VG bitumen exporter, you'll find four distinctive types: VG10, VG20, VG30, and VG40. Viscosity, a parameter signaling bitumen hardness, determines these grades, with higher numbers indicating harder bitumen. The standards set by AASHTO M226-80 and ASTM D3381-09 prescribe the grading of bitumen viscosity, expressed in degrees Celsius (140°F).
Advantages of Viscosity Grade Bitumen
VG bitumen has gained favor over penetration bitumen as it undergoes more comprehensive testing, conducted by experts in two phases. Initially, bitumen penetration was measured at the average temperature of 25 degrees Celsius. However, recognizing the limitations of this approach in hot weather conditions, testing has extended to 60 degrees Celsius and 135 degrees Celsius. The results of these tests provide several key advantages:
Savings in time and resources, as VG bitumen undergoes 7 tests compared to the 14 tests needed for penetration bitumen.
VG bitumen exhibits consistent rutting performance under hot summer conditions, distinguishing it from penetration grade bitumen.
VG bitumen is assessed for temperature susceptibility, with 25°C for fatigue cracking and 135°C for construction.
Tailored for high-traffic roads, pavements constructed with VG bitumen enjoy extended lifespans, thanks to the insights derived from viscosity testing at 135°C, which guides mixing and compaction temperatures, thus enhancing pavement durability.
By specifying a minimum kinematic viscosity value at 135°C, construction tender mix potential can be minimized.
Applications of VG Bitumen
VG bitumen boasts an array of applications, with various viscosity grades tailored to specific contexts dictated by weather and traffic conditions. VG bitumen has found utility in over 250 diverse applications, making it an irreplaceable material.
VG-30 bitumen, for instance, is widely deployed in constructing heavy-duty bitumen pavements designed to withstand substantial traffic loads. It also features prominently in the production of cutback bitumen, waterproofing materials, and in the construction of both roads and buildings. In regions characterized by hot, rainy weather or milder climates, VG-30 is a commendable choice.
Viscosity Testing
Prior to embarking on road construction, conducting a viscosity test on a bitumen sample is of paramount importance. Viscosity serves as a gauge of bitumen's fluidity. Assessing the fluidity of bitumen at specific temperatures ensures binder quality. An excessively low-viscosity bituminous binder, when used in pavement, acts merely as a lubricant, failing to fulfill its primary function of binding particles.
Highly viscous binders, on the other hand, impede the filling of voids between aggregates and the even distribution of the binder during pavement construction. This not only necessitates more effort but may also lead to a non-uniform mix. Furthermore, high-viscosity bitumen can affect workability. Selecting a binder with the appropriate viscosity is critical for achieving a uniform coating and effectively filling the gaps between aggregate particles.
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