Excerpt from Properties of Portland Cement Having a High Magnesia Content Further investigations on this subject are needed because Of the failures of mortars and concretes which have been attributed to such cements. The specifications under which cements are usually bought do not demand the making Of test pieces of the material to be tested at late periods'; but high-magnesia cements are gener ally conceded to be able to pass all the requirements demanded of the short-time tests. However, with the hydration Of the com pounds present in such cements it is claimed by some that there is a Slow but gradual increase in volume, which is manifested at late periods by low results for the strength of test pieces and finally by complete disintegration of the materialf While such cements may be satisfactory at early periods and pass the usual specifica tions, there is a strong belief in the minds of many that ultimately they will fail. As this phenomenon Of the large increase in volume accompanying the slow hydration of the constituents in high-magnesia cements can be Observed apparently only at late periods, it is essential to Obtain some. Definite information in regard to this property, if it exists. It might be possible with this infor mation to make definite predictions as to the ultimate behavior of such cements, even though short-time tests should Show them to be satisfactory. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.