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New testing equipment for short fibres |
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IIBCC 2010, Aarlborg
Dr. Ulrich Mörschel, Erich Ingelsberger
Textechno Herbert Stein GmbH & Co. KG,
Mönchengladbach/Germany
ABSTRACTFibres for cement reinforcement generally are added in short-cut form of e.g. 6 mm length. To control the
quality of the reinforced cement in an early stage, the tensile properties of the fibres need to be monitored.
Because the testing of short-cut fibres is highly difficult, as a common practice fibre producers provide a
segment of uncut tow for testing purposes. This practice bears the risk of mix-up and does not consider
damage due to fibre stress during cutting. This paper introduces a new approach using a single-fibre tensile
tester equipped with specially designed clamps, which open a window for precise determination of the tensile
properties of even short-cut fibres. In addition, a special software algorithm allows to compensate the inherent
error in elongation measurement, resulting in correct modulus and breaking elongation determination. In case
of uncut long filaments the instrument can not only test the tensile properties, but also the linear density
according to the well-proved vibroscopic principle. Since the linear density is related to the effective crosssection
of the fibre, breaking tensions (e.g. in MPa) can be directly determined with this instrument, too. In
the standard version as well as in the automated version the discussed tester it is already widely used by
leading producers of PVA and PP fibres world-wide. Finally, for further tests on the uncut filament, the
instrument can be equipped with wrap-bollard clamps to measure even coarse and highest-tenacity fibres, and
with a special device to measure the friction along an individual fibre, which makes the instrument
outstandingly suitable for tests on PVA reinforcement fibres |
