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Ductility test for bitumen

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 The ductility test for bitumen is an essential quality control procedure to evaluate the material's ability to stretch under stress without breaking. It determines the bitumen's elasticity and adhesiveness, which are critical properties for its performance in road construction. This test ensures the bitumen used in pavements can withstand temperature variations and traffic loads without cracking or deforming excessively.


The test involves heating the bitumen to a pouring consistency and filling it into a standard briquette mould. The mould, containing the bitumen sample, is cooled to room temperature and then placed in a water bath maintained at 27°C. Once prepared, the sample is tested in a ductility testing machine, where it is stretched at a uniform rate of 50 mm per minute until the bitumen thread breaks. The distance it elongates before breaking is recorded as the ductility value, measured in centimeters.


A higher ductility value indicates better flexibility and durability, which are crucial for road pavements to resist cracking under stress. Typically, a minimum value of 75 cm is recommended for paving-grade bitumen. This test ensures the material meets performance requirements, providing safe and long-lasting road surfaces.

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