Please send information on slump loss in concrete pump lines and strength tests on pumped concrete.
Slump loss generally does not occur in small line pump systems. If long lengths of flexible hose are used, a slump loss may occur because of the higher coefficient of friction in the hose line. There are no specific data available on slump loss in small line systems. However, the American Concrete Institute JOURNAL, November 1970, page 950, contains an article which points out the possible slump losses in eight-inch line systems. Strength test data before and after pumping have also not been extensively reported. The May and August 1970 issues of CONCRETE CONSTRUCTION magazine reported on several tests where the concrete was sampled before pumping and after pumping through both steel and aluminum pipe lines. Other unpublished data seem to indicate that there is no appreciable strength gain after pumping the concrete. The May 1971 American Concrete Industry JOURNAL contains the Committee Report, "Placing Concrete by Pumping Methods." This is the latest state of the art on the subject of pumping.