Consequently, it behaves more like semi-solid matter.īitumen viscosity is determined by viscometers. In the following video, our team at Infinity Galaxy shows how rotary and capillary viscometers are used to measure dynamic (ASTM D4402) and kinematic (ASTM D2170 or IS 1206) viscosity of bitumen.īelow is a list of different ways of specifying viscosity and measuring it based on the Indian bureau standard definition: The higher the viscosity of the bitumen, the harder it is to flow. This property shows how easily bitumen flows. Viscosity measurement is recommended for all industrial and engine oils.The viscosity test of bitumen measures the bitumen viscosity. Results which fall outside of the applicable grade specification are considered abnormal. It provides a specific number to compare to the recommended oil in service. For engine oils it is classified according to SAE (Society of Automotive Engineers) grade. For industrial lubricants it is classified using the ISOVG system. Viscosity is measured at 40 degrees C for industrial applications and 100 degrees C for engine oil applications. The time is multiplied by the tube's calibration factor to give a result in centistokes (cSt). ASTM method - D445. The amount of time the sample takes to flow through the calibrated portion of the tube is recorded. Gravity causes the sample to flow through the tube. Selection of the optimum fluid viscosity grade will provide the most efficient machine performance at standard operating temperatures, therefore minimizing lost time and energy and fuel costs for the operator.Ī predetermined volume of lubricant is introduced into the viscometer tube. As oil temperature increases, viscosity decreases, resulting in lower volumetric efficiency, overheating, and wear. At low temperature, excessive viscosity may result in poor mechanical efficiency, difficulty in starting, and wear. It is an important criterion in the selection of a fluid. It is the measure of the oil’s resistance to flow (shear stress) under certain conditions. The single most important property of a lubricant is its viscosity.

This test is a measurement of a lubricant's resistance to flow at a specific temperature

How to test viscosity