INVESTIGATION OF CREEP IN CONCRETE. REPORT 4. EFFECT OF SPECIMEN SIZE AND WET-SIEVING TO REMOVE AGGREGATE LARGER THAN 1-1/2 IN,
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS
Pagination or Media Count:
Creep measured on 6- by 16-in. concrete cylinders made and tested in 1957 was compared with that measured on 30- by 60-in. cylinders made and tested in 1954 for two concrete mixtures. In one series of tests both sizes of specimens were made from the same mixture proportions the maximum size of aggregate for this mixture was 1-12 in. In the other series of tests the 30- by 60-in. cylinder was made from concrete containing 6-in. maximum size aggregate, whereas the 6- by 16-in. cylinders were made from identical concrete wet-sieved to remove all aggregate larger than 1-12 in. The creep of the small specimens was corrected for autogenous length change. Since there were no control specimens of 30- by 60-in. size, the creep of specimens of that size was not corrected for autogenous length change. Test results generally confirm theories regarding creep, and show that, if practicable, testing should be done on large specimens containing the full concrete mixture. At very early loading ages, the creep of large specimens was greater than that of small specimens. At later ages, the reverse was true.
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