Date of Graduation

12-2012

Document Type

Thesis

Degree Name

Bachelor of Science in Civil Engineering

Degree Level

Undergraduate

Department

Civil Engineering

Advisor/Mentor

Hale, W. Micah

Committee Member

Fairey, Julian

Second Committee Member

Coffman, Richard A..

Abstract

The prestressed industry is moving towards adopting the Standard Test for Strand Bond (STSB) to quantify the bond capacity of prestressing strand. In the test, strand is pulled through an 18 in. cylindrical casing filled with mortar. The force corresponding to the dead end displacement of 0.1 in. is recorded and this value is used to quantify strand bond. One of the concerns of the test is the requirement of a mean mortar strength of 4,500 to 5,000 psi during testing. There is concern that this 500 psi range may be too difficult to achieve. A study was conducted to examine the effects of mortar strength on the STSB. For the study, the bond capacity of 0.50 in. and 0.60 in., Gr. 270 strand was measured at mean mortar strengths that were inside and outside the specified range. The paper also provides guidance for developing mortar mixtures that will fall within the 4,500 to 5,000 psi range. With proper quality control and trial batching, mortar mixtures meeting the STSB specification can be developed.

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