Pull-out attempt

from Wikipedia, the free encyclopedia

As a pull-out test procedures for determining the compressive strength of hardened concrete called. Pull-out tests are one of the destructive material tests that are usually carried out directly on a building. A distinction is made between two types of procedure, the LOK test and the CAPO test, the measuring principle being the same in both cases.

Measurement principle and types of procedure

The determination of the compressive strength is based on the measurement of the force that is required to pull a steel rod out of the concrete to be tested. At the desired test time, e.g. B. 28 days after concreting, the rod is pulled with a hydraulically or mechanically operated device. A calibration on samples with known compressive strength is necessary for the tests .

One possible type of procedure is the LOK test, which, however, is only suitable for new structures or components. During the manufacture of the component, the steel bar is concreted in with a small head plate and later pulled out for testing.

The CAPO test ( Cut And Pull Out ), on the other hand, is also suitable for existing buildings where a pull-out test was not planned at the time of manufacture. At the end of the steel rod for the CAPO test there is an expansion ring that is inserted into a pre-drilled hole. Similar to a dowel , the expansion ring anchors the rod in the concrete, so that measurements can be carried out using the same principle as with the LOK test.

Web links