Needle penetration

Experimental setup of needle penetration. Left at the beginning, right at the end of the experiment. The experiment takes place in a water bath.

The needle penetration is a test method in road construction . The values ​​determined can be used to make statements about the hardness of the bitumen used . The procedure is described in DIN EN 1426.

features

During needle penetration, a standardized needle (100 g) is loaded with a weight for a certain time (5 seconds) at a specified temperature (25 ° C) and the penetration depth of the needle is determined in tenths of a millimeter. The numerical values ​​in the name of a bitumen (for example bitumen 50/70, 70/100, 160/220) indicate the range in which the penetration depth of the needle lies with these types. For example, 50/70 means that the penetration depth is between 5 and 7 mm.

So that the results of different tests can be compared with each other, the test conditions are specified in the test designation. The designation test DIN EN 1426 25-100-5 means that the needle penetration must take place at 25 degrees Celsius, whereby the needle must be loaded with 100 grams. The exercise interval is 5 seconds. The experiment takes place in a water bath. The test is carried out three times, whereby the points of attachment of the needles on the bitumen surface must be about 1 cm apart.

See also

• Fraass breaking point
• RuK softening point

swell

• Joachim Lorenz: Road Construction Manual , Fraunhofer IRB Verlag, 2006, ISBN 3-8167-7083-5