On the basis of freezing and thawing tests of air-entrained concretes having poor quality cherts as course aggregates subjected to three different treatments for improving durability, the following conclusions have been derived: 1. Removal of cherts lighter than the BSSD specific gravity of 2.5 by heavy liquid definitely improved the durability of the concrete. 2. Combining 50 percent durable aggregate (1/2"-1/4" size) with 50 percent cherts (1"-1/2" size) did not show any significant improvement in durability over that containing 100 percent chert. 3. As much as 12 percent chert could be blended with durable aggregate without an appreciable reduction in durability. / Master of Science

The effects of maximum size coarse aggregate on the relationship between accelerated strength and 14-day normally cured strength of normal and superplasticized concrete have been investigated. The results obtained show that differences among maximum size coarse aggregates are greater in normal concrete than in superplasticized concrete in strength-producing properties. Among the various sizes of aggregates investigated, one-half inch maximum size of coarse aggregate exhibited higher strength producing properties. This report includes the test results as well as the procedures for the preparation and testing of concrete specimens. These specimens were prepared and tested at the concrete laboratory at Virginia Polytechnic Institute and State University. / Master of Science / incomplete_metadata

Master of Science

This thesis is an investigation of the effect of welding heat on the properties of hardened concrete. In precast concrete structures, where the bearing plates are embedded in the concrete, the welding heat on these plates, generated by the electric arc, penetrates into the concrete. It has been known for many years that high temperatures will lower the modulus of elasticity and the ultimate strength. This thesis is concerned with the “critical” temperatures at which losses begin and the arc energy required to develop this temperature at a reasonable depth into the concrete. In the investigation, the “critical” temperature, using limestone aggregate concrete that might be typical for precast construction, was found to be between 900°F and 1,000°F. The investigation, to determine the arc energy required to develop this temperature, was halted when under severe heating, where the arc burned through both plates, the maximum temperature at a point one half inch from the bearing plate was 710°F. Although cracking was severe in the immediate vicinity of the plate, the moduli of elasticity were lowered only slightly and the welding heat was not high enough to affect the ultimate strength. / Master of Science

"June 2002" Includes bibliographical references (leaves 349-374)

"June 2002" / Includes bibliographical references (leaves 349-374) / xxxix, 416 leaves : ill., plates ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2002

This report details the design and construction of an AASHTO Type IV prestressed girder and a PCI BT-56 prestressed girder. It also details the shear testing and shear performance of the BT-56 girder. The results are compared with results from previous research dating back to 1986. Finally, all research was compared with the AASHTO Standard (2002), AASHTO LRFD (1998) and AASHTO LRFD (2004) Specifications to examine thier overall accuracy in predicting shear strengths.

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / The major contribution of this thesis is towards the shear capacity and shear failure mechanism of reinforced concrete beams with adhesively bonded transverse near surface mounted fiber reinforced plastic plates. In shear strengthening, there are two forms of plate debonding that interact with each other consisting of intermediate crack debonding that is governed by the axial forces in the plate are induced by shear deformations. This research considers both forms of debonding and in particularl their interaction. -- From abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1283733 / Thesis (Ph.D.) -- University of Adelaide, School of Civil and Environmental Engineering, 2007

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / The major contribution of this thesis is towards the shear capacity and shear failure mechanism of reinforced concrete beams with adhesively bonded transverse near surface mounted fiber reinforced plastic plates. In shear strengthening, there are two forms of plate debonding that interact with each other consisting of intermediate crack debonding that is governed by the axial forces in the plate are induced by shear deformations. This research considers both forms of debonding and in particularl their interaction. -- From abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1283733 / Thesis (Ph.D.) -- University of Adelaide, School of Civil and Environmental Engineering, 2007

Call number: LD2668 .T4 1985 K57 / Master of Science