The CBR value must be determined by laboratory testing in accordance with the principles of BS 1377 (soil) or BS1924 (material with hydraulic binder), with the following requirements:
Conventional steel test moulds may be unsuitable for some TMF materials (owing to the requirement to remove coarse aggregate >20 mm in size) and in-situ testing may therefore need to be considered. The preparation of TMF test samples may include test cores extracted from site.
Following preparation, the test samples are stored at ambient temperature for up to 90 days after the placement of the material on site.
The laboratory CBR test is performed on samples in a soaked condition (soaked for 4 days before testing).
The tests are carried out by a UKAS accredited laboratory unless mutually agreed otherwise.
On site, a recognised appropriate direct or indirect equivalent test method may be used.