Masters Theses

Kristian Krc

Keywords and Phrases

Cold-Joint; Lightweight Aggregate; Lightweight Concrete; Monolithic; Push-off; Shear-Friction

Abstract

"This thesis reports the results of research initiated to evaluate the influence of lightweight aggregate type and casting procedure on shear transfer across an interface of concretes cast at different times. The topic of shear transfer has been evaluated and revisited in recent PCI Design Handbooks. In this test program, a series of cold joint as well as monolithic specimens are evaluated. The peak shear strength and post peak behavior are examined. The experimental matrix included 28 push-off specimens that were either cast monolithically or cast at different times creating the condition referred to as a cold joint. The variables included lightweight aggregate type (expanded shale, expanded slate, expanded clay); unit weight (88 - 148 pcf); and shear interface condition (monolithic uncracked, monolithic pre-cracked, cold joint roughened, cold joint smooth). A load cell, six DC-LVDTs, and three strain gages were used to monitor the behavior of each specimen.

Results suggest that the shear strength of monolithic specimens increased with increasing concrete unit weight. The shear strength of cold joint specimens with an intentionally roughened interface increased as the concrete unit weight increased. The shear strength of cold joint specimens with smooth interface was independent of concrete unit weight. The shear strength was predicted conservatively by the PCI Design Handbook 7th Edition and the ACI 318-14 code for all cold joint interface specimens. The effective coefficient of friction µe used by the PCI Design Handbook was found to be conservative for both sand-lightweight and all-lightweight cold joint specimens regardless of the type of lightweight aggregate used. This research was sponsored by Precast/Prestressed Concrete Institute (PCI) and the American Concrete Institute (ACI) Concrete Research Council (CRC)"--Abstract, page iii.

Advisor(s)

Sneed, Lesley

Committee Member(s)

Myers, John
ElGawady, Mohamed
Meinheit, D. (Donald F.)

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering

Sponsor(s)

Precast/Prestressed Concrete Institute
American Concrete Institute. Concrete Research Council

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2015

Pagination

xix, 167 pages

Note about bibliography

Includes bibliographical references (pages 163-166).

Rights

© 2015 Kristian Krc, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Lightweight concrete -- Testing
Precast concrete -- Testing
Aggregates (Building materials)
Shear (Mechanics) -- Mathematical models
Friction -- Mathematical models

Thesis Number

T 10788

Electronic OCLC #

936207720

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