As was stated before, the purpose of this problem was to find out the effect of freezing on mortar at different hours after mixing. This was a continuation of the work done by G.H. Harris in 1945. It was hoped that by using different materials, steel molds, and by molding, freezing and testing the specimens as accurately as was possible to do so with the equipment available the peculiar results obtained by Harris could either be verified or disproved. The results obtained by this problem were very irregular but did show a slight trend and did not show the great difference in strength over a short period of time as was shown by Harris’s results. To get a definite answer a large number of samples should be run for each different time of set before freezing. A large variety of materials should be used and it is also believed that test cylinders 6”x12” would give better results. / Master of Science