File:An investigation of hooped concrete columns (1914) (14775172664).jpg

Identifier: investigationofh00thom (find matches)
Title: An investigation of hooped concrete columns
Year: 1914 (1910s)
Authors: Thomas, Howard Rice
Subjects: Columns, Concrete Theses
Publisher:
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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of Mr. D. A. Abrams,by mem experienced inmaking concrete, who havemade the test specimens used in thelaboratory for a number of years. The materials were measured inbuckets, and then weighed as a check on the measurements. Thematerials were thoroughly mixed while dry, and then mixed forfive minutes after the water was added. Enough water was usedto give a medium wet mixture which would thoroughly cover thespirals. The amount of water used was measured in each case. In some cases two five-ft. columns were made from onebatch cf concrete, but in no case we^e these two columns ofthe same series. In putting the concrete into the forms wheretwo columns were made from the same batch, alternate bucketfulswere placed in each in order to secure both columns as nearlyalike as possible. This precaution of not making two columns of the same series from the same batch has been found necessary in order that any accidental variation in a given batch may not cause phenomena===== —=■ ■ — — 1
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13 that might otherwisebe ascribed to the effect of the variableof that series. This precaution has too often been disre-garded in making concrete test specimens. In making the 30-ft. columns, two batches of concretewere necessary. The first batch was mixed and turned out onthe floor, and then the second mixed and dumped on it. Thesetwo were then thoroughly stirred together to secure a homogenousconcrete. A planed cast iron bed plate was used for each column.In setting up the form, this bed plate was carefully leveled.The spiral in the form was placed on the plate and plumbed,braces being used to hold it in position. The concrete washandled by the bucketful, and was thoroughly stirred as eachbucketful was added. The tamper, which was used for stirring,rather than tamping, consisted of an iron head about 3-in. indiameter with a sectional pipe handle. The concrete was toowet to be tamped, but it was thoroughly stirred in order to causeit to flow around and cover the spirals and also to

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