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Parametric Study of Self -Consolidating Concrete UNLV Retrospective Theses & Dissertations 1-1-2008 Parametric study of self -consolidating concrete Hamidou Diawara University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/rtds Repository Citation Diawara, Hamidou, "Parametric study of self -consolidating concrete" (2008). UNLV Retrospective Theses & Dissertations. 2837. http://dx.doi.org/10.25669/kdxy-kly0 This Dissertation is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Dissertation in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Dissertation has been accepted for inclusion in UNLV Retrospective Theses & Dissertations by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. PARAMETRIC STUDY OF SELF-CONSOLIDATING CONCRETE by Hamidou Diawara Bachelor of Science National School of Engineering, Mali 1987 Master of Science Southern Illinois University at Carbondale 1998 A dissertation submitted in partial fulfillment of the requirements for the Doctorate of Philosophy Degree in Civil and Environmental Engineering Department of Civil and Environmental Engineering Howard R. Hughes College of Engineering Graduate College University of Nevada, Las Vegas December 2008 UMI Number: 3352169 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI UMI Microform 3352169 Copyright 2009 by ProQuest LLC. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 E. Eisenhower Parkway PC Box 1346 Ann Arbor, Ml 48106-1346 Copyright by Hamidou Diawara 2008 AU rights reserved Dissertation Approval UNTV The Graduate College University of Nevada, Las Vegas December 15 20^8 The Dissertation prepared by Hamidou Diawara Entitled Parametric Study of Self-Consolidating Concrete is approved in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Civil and Environmental Engineering Examination Committee Chair Dean of the Graduate College Exmnination Committee MeiftBer Examinatiàé Committee Member Examination Committee Member/ Graduate College Faculty Representative Efâarnmanon Commi/tee 1017-52 11 ABSTRACT Parametric Study of Self-Consolidating Concrete by Hamidou Diawara Dr. Nader Ghafoori, Examination Committee Chair Professor and Chairman of Civil and Environmental Engineering Department University of Nevada, Las Vegas The research investigation presented herein was intended to study the influence of parameters, such as aggregate size, admixture source, hauling time, and temperature on the fresh and hardened properties of three distinct groups of self-consolidating concretes (SCC). Within each group, the selected SCCs were made with a constant water-to- cementitious materials ratio, a imiform cementitious materials (cement and fly ash) content, and a constant coarse-to-fme aggregate ratio that provided the optimum aggregate gradation. Three coarse aggregate sizes (ASTM C 33 # 8 , #7, and #67) obtained from two different quarries were investigated. Four sources of polycarboxylate- based high range water-reducing admixtures (HRWRA) and viscosity modifying admixtures (VMA) were used. All raw materials were evaluated for their physico­ chemical characteristics. The investigation presented herein was divided into two major phases. The first 111 phase aimed at: ( 1) comparing the optimum dosage requirements of four different sources of polycarboxylate-based HRWRA and VMA in attaining the target slump flow of 508 mm (20 inches), 635 mm (25 inches), and 711 mm (28 inches), T 50 of 2 seconds or more, and a visual stability index (VSI) of 0 (Highly stable concrete) or 1 (Stable concrete), (2) evaluating the flow rate/plastic viscosity, static and dynamic stabilities, passing ability, and filling ability of the selected self-consolidating concretes, and (3) examining the properties of the trial self-consolidating concretes as related to air content, bleeding, time of setting, adiabatic temperature, demolded unit weight, compressive strength and modulus of elasticity. In the second phase, the influence of hauling time, temperature, and combined hauling time and temperature on the fresh properties of the selected self-consolidating concretes was evaluated. Seven different temperatures (43, 36, 28, 21, 14, 7, and -0.5 °C (109, 96, 83, 70, 57, 44, and 31 °F)) and nine different hauling times (10, 20, 30, 40, 50, 60, 70, 80, and 90 minutes) were used to determine the loss in unconfined workability, dynamic stability, and flow ability rate of the designed matrices. The adverse effect of the above-mentioned variables was remediated by way of overdosing and retempering techniques which resulted in achieving the desired fresh characteristics of the designed self-consolidating concretes for different hauling times and temperatures. IV TABLE OF CONTENTS ABSTRACT..................................................................................................................................iii LIST OF TABLES......................................................................................................................xii LIST OF FIGURES....................................................................................................................xv ACKNOWLEDGEMENTS.......................................................................................................xx CHAPTER 1 INTRODUCTION............................................................................................1 1.1 General background on self-consolidating concrete .............................................. 1 1.2 Constituent’s materials and their physico-chemical properties ........................... 4 1.2.1 Aggregates ............................................................................................................ 4 1.2.2 Portland cem ent ....................................................................................................5 1.2.2.1 Manufacturing process of Portland cem ent .........................................7 1.2.2.2 Chemistry of Portland cement ...............................................................8 1.2.2.3 Portland cement hydration ................................................................... 12 1.2.3 Chemical admixtures.........................................................................................15 1.2.3.1 Air-entraining admixtures .................................................................... 17 1.2.3.1.1 Function ....................................................................................... 17 1.2.3.1.2 Chemical composition ...............................................................19 1.2.3.1.3 Mechanism of action .................................................................20 1.2.3.2 Water-reducing admixtures or normal plasticizers .......................... 21 1.2.3.2.1 Function .......................................................................................21 1.2.3.2.2 Chemical composition ...............................................................22 1.2.3.2.3 Mechanism of action .................................................................24 1.2.3.2.3.1 Adsorption ...................................................................... 25 1.2.3.2.3.2 Electrostatic repulsion ...................................................29 1.2.3.3 High range water-reducing admixture or superplasticizers ............ 32 1.2.3.3.1 Function .......................................................................................32 1.2.3.3.2 Chemical composition ...............................................................32 1.2.3.3.3 Mechanism of action .................................................................33 1.2.3.3.4 Superplasticizer in cement hydration products ..................... 35 1.2.3.3.5 Time of addition of superplasticizer ........................................35 1.2.3.3.6 Effect of chemical structure on polycarboxylate polymer .......................................................................................36 1.2.3.4 Viscosity modifying admixture (VMA) .............................................38 1.2.3.4.1 Function .......................................................................................38 1.2.3.4.2 Chemical composition ...............................................................39 1.2.3.4.3 Mechanism of action ................................................................40 1.2.3.5 Admixture compatibility ...................................................................... 41 1.2.4 Mineral admixtures............................................................................................ 42 1.2.4.1 Fly ash .....................................................................................................42
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