During 1945 it was apparent that the use of aluminium would greatly increase in building and civil engineering and, at the request of the Aluminium Development Association, BRS undertook a programme of work intended to give a clearer understanding of embedding aluminium in various building mortars, plasters and concretes. The tests were planned under defined conditions of exposure up to 10 years, and were commenced in 1948. The work has been completed and is described and discussed in the present paper.