This investigation covered a general study of the effects of the partial loads on the twenty-eight day strength of concrete. Special emphasis was placed on those loads and times of loading that produced the greatest strengths. The work was done using one mix. However, the results for this mix will probably be characteristic of other mixes. all the work,including the making and testing of cylinders, tests for aggregates, slump tests, etc., was done according to the A. S. T. M. standards. It is quite natural that,while investigating one problem, many other interesting problems are thought of in relation to the work, There are some problems related to partial loads that might warrant future study and research, some of these being as follows: 1. A study of the effects of partial loads during the early curing period on concrete beams. 2. A study of the effects of partial loads during the early curing period on various mixes of concrete. 3. A study of conditions actually existing in structures. 4. A study of sections of concrete cylinders cut in various planes which would include concrete that had been partially loaded and concrete that had not been partially loaded. This might lead to a discovery of why the effects of partial loading are produced. / Master of Science