Ductility test

The ductility test indirectly measures the tensile properties of the bituminous materials and may be used for specification requirements. Because most of the typically used paving bitumens meet the specification requirement at 25°C, its usefulness is questioned by many researchers. 

During the ductility test, the bitumen specimen is pulled apart at a specified speed and temperature condition (50 mm/min, 25°C) until it ruptures or reaches the length limitations of the machine. The elongation length at rupture, measured in centimetres, is defined as the bitumen s ductility value. The test is performed on three briquette specimens and the average of the three values is determined. In the event of discrepancy of results, they should be within the acceptable range set by the specification (AASHTO T 51 2009 ASTM D 113 2007). 

The specimens are prepared by pouring the heated bitumen into ductility brass moulds assembled on a brass or metallic plate. Before pouring the bitumen, the surface of the metallic plate is coated with a release agent (typically a mixture of glycerin and talc powder). This prevents specimen from sticking to the plate and to the detachable middle part of the mould (side pieces), after allowing the filled mould to cool to room temperature. 

It should be pointed out that the same apparatus is used for the elastic recovery test. For details, see Section 4.6. 

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Ductility Tests. The ductihty of plated metals differs considerably from the corresponding thermally cast metals. Additionally, ductihty which is an important property if parts are to be deformed after plating, varies with the chemical composition of the plating solution, as well as the operating conditions of a given plating process. Ductihty can also be important when plated parts are stressed in use. Some metal deposits have coefficients of... 

Tensile testing or a hardness test is a basic requirement of most metal specifications. Some product specifications also require impact-testing, bend and other ductility tests, proof testing, flange or flare tests. The size of the sample may limit which tests can be performed. Macro, superficial, and micro-hardness tests are routinely done in failure analysis even if the original product specification did not require them. 

Finally, a criterion was discovered. It was the notched beam ductility test, which seemed to pinpoint the abnormal behavior and to discriminate between acceptable and unacceptable materials of this type. 

Figure 4-2. Typical results from notched-beam ductility test.

ASTM D256 Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics. Used to determine the resistance of a plastic specimen to impact by a pendulum-type hammer. Specimens contain a milled notch and depending upon the test method, failure may be brittle or ductile. Test results are reported in terms of energy absorbed per unit of specimen width or per unit of cross-sectional area under the notch. 

The force ductility test is performed on bituminous binders, in particular those of polymer-modified bitumens, for the determination of the conventional energy of bituminous binders from tensile characteristics. 

The force ductility test is carried out in accordance to CEN EN 13589 (2008), using the ductilometer apparatus, which is equipped with an additional device capable of measuring the tensile force within the range of 1 to 300 N to an accuracy of 0.1 N (see Figure 4.3). 

The force ductility test is also described in AASFITO T 300 (2011). 

The test is carried out in accordance to CEN EN 13398 (2010) and ASTM D 6084 (2006), or AASHTO T 301 (2013), by using the same apparatus, mould and procedure as in the ductility test. The testing temperature is usually 25°C. The only difference is that the bituminous specimen is not stretched until rupture but only up to a predetermined elongation (200 mm by CEN EN 13398 2010). 

The elastic recovery test, because of its similarity to the ductility test, is also sometimes called the modified ductility test. 

The tensile test is an alternative to the force ductility test for the determination of the tensile properties and cohesion of bituminous binders, particularly polymer-modified binders. 

The test is performed according to CEN EN 13587 (2010) at a temperature of 5 C using the ductilometer apparatus as in the force ductility test but at a constant traction rate of... 

AASHTO T 300.2011. Force ductility test of asphalt materials. Washington, DC American Association of State Highway and Transportation Officials. 

This theory is illustrated graphically for the four states of biaxial stress shown in Figure 1-3. This theory correlates even better with ductile test specimens than the maximum shear stress theory. 

Ger] Dilatometry, density, hardness (Brinell), stress and ductility tests Tensile elongation, density, hardness, porosity, ductility... 

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