The paper presents details of the development of a deep freeze cabinet and of a cold room for carrying out the Road Research Laboratory frost heave test and the results obtained in the two testing facilities are compared. The majority of the tests reported were undertaken on burnt and on unburnt colliery shale, both in their natural state and when stabilised with cement, and an indication is given of the scatter in the results of tests on nominally similar specimens. The paper includes mention of a commercial deep freeze unit developed as a result of the work reported in the paper.