Title page for ETD etd-11092012-040056


Type of Document Master's Thesis
Author Jamil, Khan Shahid
URN etd-11092012-040056
Title Effect of pre-stressing on the durability of portland cement concrete
Degree Master of Science
Department Civil Engineering
Advisory Committee
Advisor Name Title
Walker, Richard D. Committee Chair
Gray, George A. Committee Member
Morris, Henry M. Committee Member
Payne, William W. Committee Member
Keywords
  • Portland cement
Date of Defense 1964-12-05
Availability restricted
Abstract

In view of the fact that prestressed concrete is extensively used in bridge construction and that it holds potentialities for eventual use in pavement construction, and that methods must be investigated to utilize an otherwise rejected aggregate which cannot be used for its poor performance under natural weathering, it has become of paramount importance that further efforts be made to evaluate the effect of prestressing on the durability of concrete.

The purpose of this thesis was twofold: 1) To study the durability of prestressed concrete made of poor-performing aggregate; 2) To compare the freezing and thawing effects on prestressed concrete with those on ordinary concrete.

Two mix designs having different proportions of poor performing aggregate were used in this study. Half the number of specimens were post-tensioned after they had been cured for a period of 13 to 18 days in water, and were then replaced in the curing room for 24 hours, Level of prestress was 600 psi. Before transferring the specimens - both prestressed and non-prestressed - into freezing and thawing apparatus, they were tested for fundamental transverse frequency and initial weight and length measurements were recorded. Thereafter, transverse frequency, weight, length change and temperature change measurements were made periodically. The relative dynamic modules of elasticity and durability factor were then calculated for each specimen.

On the basis of the results furnished by these tests, it may be concluded that prestressing improves the durability of concrete made of poor performing aggregate and that the magnitude of improvement in the durability ef concrete tends to diminish with increasing proportion of good performing aggregate.

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