ASTM D36 for softening point of bitumen (Ring-and-Ball apparatus)
ASTM D36 standard test method for softening point of bitumen (Ring-and-Ball apparatus)
1. Scope
1.1 This test method covers the determination of the softening point of bitumen in the range from 30 to 157°C (86 to 315°F) using the ring-and-ball apparatus immersed in distilled water (30 to 80°C), USP glycerin (above 80 to 157°C), or ethylene glycol (30 to 110°C).
1.2 The values stated in SI units are to be regarded as the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D92 Test Method for Flash and Fire Points by Cleveland Open Cup
D140 Practice for Sampling Bituminous Materials
D3461 Test Method for Softening Point of Asphalt and Pitch (Mettler Cup-and-Ball Method)
E1 Specification for ASTM Thermometers
3. Summary of Test Method
3.1 Two horizontal disks of bitumen, cast in shouldered brass rings, are heated at a controlled rate in a liquid bath while each supports a steel ball. The softening point is reported as the mean of the temperatures at which the two disks soften enough to allow each ball, enveloped in bitumen, to fall a distance of 25 mm (1.0 in.).
4. Significance and Use
4.1 Bitumens are viscoelastic materials without sharply defined melting points; they gradually become softer and less viscous as the temperature rises. For this reason, softening points must be determined by an arbitrary and closely defined method if results are to be reproducible.
4.2 The softening point is useful in the classification of bitumens, as one element in establishing the uniformity of shipments or sources of supply, and is indicative of the tendency of the material to flow at elevated temperatures encountered in service.
