The CBR test – California Bearing Ratio
Since 2008, the dynamic CBR test (California Bearing Ratio) according to TP Gestein-StB Part 5.6 has been undertaken in the laboratory on crushed samples with a maximum grain size of 22 mm and with an oversize portion of not more than 50% as a rule. This test can also be used as an alternative to the static CBR test according to TP BF – StB Part B 7.1 . Due to the short time required, it is used above all during in-house monitoring tests for production control during the manufacture of mineral aggregate mixtures from steel slag. Advantageous in comparison to the CBR test according to TP BF – StB Part B 7.1  is the elimination of the need for the loading frame and the related static loading device.
The dynamic CBR value is a complex strength characteristic that is dependent on the strength, the grain shape, the frost resistance and the grain roughness of the individual grain, the grain composition, the fines content, the water content and the compaction of the mineral aggregate mixture.
It can be used, e.g., to assess the sensitivity to frost or to estimate suitability for traffic and the compactability, as well as the load-bearing capacity of the mineral aggregate mixtures laid.