Temperature Changes in Mass Concrete

If free to move, all structural materials undergo changes in length due to changes in temperature, and, if not free to move, a stress in the material is produced equal to that required to produce the deformation in length. In order to determine the extent of this change in length, or the corresponding stress in the material, it becomes necessary to know the range in temperature to which the material is to be subjected. In large masses of masonry, the changes in temperature at varying distances from the exposed faces are not known, and, largely due to this fact, the changes in length of large masses of masonry, together with the actual internal distribution of temperature stresses, are among the most indefinite factors in the design of such structures. The purpose of this paper is to place before the Society the results, thus far obtained, of experiments being made to determine the changes of temperature in the concrete of the Arrowrock Dam, together with a description of the apparatus used.