Handbook of Thermal Analysis of Construction Materials

Handbook of Thermal Analysis of Construction Materials

(Parte 1 de 5)

V.S. Ramachandran, Ralph M. Paroli, James J. Beaudoin, and Ana H. Delgado

Institute for Research in Construction National Research Council of Canada Ottawa, Ontario, Canada

WILLIAM ANDREW PUBLISHING Norwich, New York, U.S.A.

Copyright © 2002 by Noyes Publications

No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without permission in writing from the Publisher.

Library of Congress Catalog Card Number: 2002016536 ISBN: 0-8155-1487-5 Printed in the United States

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Library of Congress Cataloging-in-Publication Data

Ramachandran[et al.].

Handbook of thermal analysis of construction materials / edited by V.S. p. cm. -- (Construction materials science and technology series)

1. Building materials--Thermal properties--Handbooks, manuals, etcI.

Includes bibliographical references and index. ISBN 0-8155-1487-5 (alk. paper) Ramachandran, V. S. (Vangipuram Seshachar) I. Series

TA418.52 .H36 2002 691'.028'7--dc21 2002016536

Editor V. S. Ramachandran, National Research Council Canada

CONCRETE ADMIXTURES HANDBOOK; Properties, Science and Technology, Second Edition: edited by V. S. Ramachandran

CONCRETE ALKALI-AGGREGATE REACTIONS: edited by P. E. Grattan-Bellew

CONCRETE MATERIALS; Properties, Specifications and Testing, Second Edition: by Sandor Popovics

CORROSION AND CHEMICAL RESISTANT MASONRY MATERIALS HANDBOOK: by W. L. Sheppard, Jr.

HANDBOOK OF ANALYTICAL TECHNIQUES IN CONCRETE SCIENCE AND TECHNOLOGY; Principles, Techniques, and Applications: edited by V. S. Ramachandran and James J. Beaudoin

HANDBOOK OF CONCRETE AGGREGATES; A Petrographic and Technological Evaluation: by Ludmila Dolar-Mantuani

HANDBOOK OF FIBER-REINFORCED CONCRETE; Principles, Properties, Developments, and Applications: by James J. Beaudoin

HANDBOOK OF POLYMER MODIFIED CONCRETE AND MORTARS; Properties and Process Technology: by Yoshihiko Ohama

HANDBOOK OF THERMAL ANALYSIS OF CONSTRUCTION MATERIALS: by V. S. Ramachandran, Ralph M. Paroli, James J. Beaudoin, and Ana H. Delgado

LIGHTWEIGHT AGGREGATE CONCRETE; Science, Technology, and Applications: by Satish Chandra and Leif Berntsson

WASTE MATERIALS USED IN CONCRETE MANUFACTURING: edited by Satish Chandra

Contents xv

1 Thermoanalytical Techniques1
1.0 INTRODUCTION1
2.0 CLASSICAL TECHNIQUES2
Calorimetry2
2.2 DSC5
2.3Calibration of DTA and DSC7
2.4 Thermogravimetry12
2.5 High Resolution TG14
3.0 MODERN TECHNIQUES20
3.1 Thermomechanical Analysis (TMA)20
3.2 Dynamic Mechanical Analysis (DMA)2
3.3 Dielectric Analysis (DEA)23
3.4 Conduction Calorimetry26
REFERENCES30
2Introduction to Portland Cement Concrete35
1.0 PRODUCTION OF PORTLAND CEMENT36
2.0 COMPOSITION37
3.0 INDIVIDUAL CEMENT COMPOUNDS38
3.1 Tricalcium Silicate38
3.2 Dicalcium Silicate43
3.3 Tricalcium Aluminate4
3.4 The Ferrite Phase45
MINERALS46
6.0 PROPERTIES OF CEMENT PASTE51
6.1 Setting51
6.2 Microstructure52
6.3 Bond Formation53
6.4 Density54
6.5 Pore Structure54
6.6Surface Area and Hydraulic Radius54
6.7 Mechanical Properties5
7.0 PERMEABILITY OF CEMENT PASTE56
8.0 DIMENSIONAL CHANGES57
9.0 MODELS OF HYDRATED CEMENT57
10.0 MATHEMATICAL MODELS58
1.0 CONCRETE PROPERTIES60
1.1 Workability60
1.2 Setting61
1.3 Bleeding and Segregation61
1.4 Mechanical Properties61
12.0 DURABILITY OF CONCRETE62
13.0 ALKALI-AGGREGATE EXPANSION63
14.0 FROST ACTION63
15.0 SEA WATER ATTACK64
16.0 CORROSION OF REINFORCEMENT65
17.0 CARBONATION OF CONCRETE65
18.0 DELAYED/SECONDARY ETTRINGITE FORMATION6
REFERENCES67

xvi Contents

Compounds71
1.0 INTRODUCTION71
2.0 RAW MATERIALS73
3.0 CLINKERIZATION7
4.0 SYNTHESIS OF CEMENT PHASES82
5.0 POLYMORPHISM IN SILICATES87
6.0 HYDRATION89
6.1 Calcium Silicates89
6.2 Calcium Aluminates9
6.3 Calcium Aluminates Plus Gypsum104
7.0 PORTLAND CEMENT1
8.0 CaO-SiO2-Al2O3-H2O AND RELATED SYSTEMS118
9.0 DURABILITY ASPECTS122
9.1 Aggregates122
9.2 Magnesium Oxide124
9.3 High Temperature Effects126
9.4 Freezing-Thawing Processes127
9.5 Carbonation131
9.6 Chemical Attack134
9.7 Aged Concrete135
4 Introduction to Concrete Admixtures143
1.0 INTRODUCTION143
2.0 ACCELERATORS145
2.1Effect of Calcium Chloride on Calcium Silicates146
2.2Effect of Calcium Chloride on Calcium Aluminate149
2.3Effect of Calcium Chloride on Cement150
2.4Effect of Calcium Chloride on Concrete151
2.5 Triethanolamine (TEA)153
2.6 Formates156
2.7 Other Non-Chloride Accelerators159
3.0 WATER REDUCERS AND RETARDERS162
3.1 Introduction162
3.2 Retarders164
3.3 Water Reducers167
4.0 SUPERPLASTICIZERS169
5.0 AIR-ENTRAINING AGENTS173
6.0 MINERAL ADMIXTURES174
6.1 Fly Ash175
6.2 Slag176
6.3 Silica Fume176
7.0 MISCELLANEOUS ADMIXTURES177
7.1 Expansion Producers178
7.2 Pigments178
7.3 Dampproofing and Waterproofing Admixtures178
7.4 Pumping Aids178
7.5 Flocculating Admixtures178
7.6Bacterial, Fungicidal, and Insecticidal Admixtures179
7.7 Shotcreting Admixtures179
7.8 Antiwashout Admixtures179
7.9 Corrosion Inhibiting Admixtures179
7.10 Alkali-Aggregate Expansion Reducing Admixtures180
7.1 Polymer-Modified Mortars/Concrete180
7.12Admixtures for Oil Well Cements180
7.13 Antifreezing Admixtures181
REFERENCES182
5 Accelerating Admixtures189
1.0 INTRODUCTION189
2.0 CALCIUM CHLORIDE190
3.0 NON-CHLORIDE ACCELERATORS202
REFERENCES218
6Retarding and Water Reducing Admixtures221
2.0 LIGNOSULFONATES2
2.1 Tricalcium Aluminate2
Lignosulfonate-Water224
Lignosulfonate-Water225
2.4 Tricalcium Silicate-Lignosulfonate-Water226
2.5 Dicalcium Silicate-Lignosulfonate-Water System229
Lignosulfonate-Water System230
2.7 Cement-Lignosulfonate-Water System232
3.0 SUGAR-FREE LIGNOSULFONATE235
4.0 HYDROXYCARBOXYLIC ACIDS238
5.0 SUGARS239
6.0 PHOSPHONATES240
RETARDERS245
8.0 SLUMP LOSS248
9.0 ABNORMAL SETTING251
10.0 READY-MIX CONCRETE252
1.0 OTHER ADMIXTURES254
12.0IDENTIFICATION OF WATER REDUCERS/RETARDERS254
REFERENCES257
7 Superplasticizing Admixtures261
1.0 INTRODUCTION261
2.0 TRICALCIUM ALUMINATE262
3.0 TRICALCIUM ALUMINATE-GYPSUM SYSTEM265
4.0 TRICALCIUM SILICATE269
5.0 CEMENT273
6.0 THERMAL ANALYSIS OF SUPERPLASTICIZERS287
REFERENCES289
Other Additions293
1.0 INTRODUCTION293
2.0 FLY ASH294
3.0 SILICA FUME300
4.0 SLAGS308
5.0 RICE HUSK ASH319
6.0 METAKAOLINITE323
7.0 NATURAL POZZOLANS328
MIXTURES332
9.0 MISCELLANEOUS ADDITIVES338

Contents xix

Binders and Concrete355
1.0 INTRODUCTION355
2.0 MAGNESIUM OXYCHLORIDE CEMENT356
2.1 Description356
2.2 Hydration Reactions356
2.3 Microstructure Development357
2.4 Strength Development357
2.5 Resistance To Water360
3.0 MAGNESIUM OXYSULFATE CEMENT360
3.1 Hydration360
3.2 Strength Development361
4.0 CALCIUM ALUMINATE CEMENTS362
4.1 Description362
4.2 Hydration363
4.3 Strength Development365
4.4Strength and the Conversion Reaction365
4.5 Inhibition of C3AH6 Formation366
4.6 Durability367
4.7 Chemical Admixtures367
4.8 Refractory Applications369
CEMENT BLENDS370
5.1 Introduction370
5.2 Hydration370
5.3Setting Behavior and Ettringite Nucleation372
5.4 Early Strength Development373
5.5 CAC-Based Expansive Cement Reactions375
5.6 Chemical Admixtures378
6.0 PHOSPHATE CEMENT SYSTEMS379
6.1 Description379
7.0 MAGNESIA PHOSPHATE CEMENT BINDERS381
7.1 Mechanical Properties381
7.2 Additives385
7.3 Calcium Phosphate-Based Materials386
7.4 Lime Silico-Phosphate Cement387
8.0 REGULATED-SET CEMENT388
8.1 Description388
8.2 Paste and Mortar Hydration388
JET SET-BASED CEMENT SYSTEMS392
9.1Strength, Microhardness, and Modulus of Elasticity392
9.2 Durability395
9.3 Gypsum395

9Introduction to Non-Portland Cement 5.0PORTLAND CEMENT–CALCIUM ALUMINATE 9.0MECHANICAL PROPERTIES AND DURABILITY OF REFERENCES ......................................................................................... 397

10 Non-Portland Rapid Setting Cements403
1.0 INTRODUCTION403
2.0 CALCIUM ALUMINATE CEMENTS404
2.1 Basic Reactions404
Aluminate Cements405
3.0 JET SET (REGULATED-SET) CEMENT422
3.1 Hydration of 11CaO•7Al23•CaFS422
OXYSULFATE CEMENT SYSTEMS430
5.0 ZINC OXYCHLORIDE CEMENT437
6.0 MAGNESIA-PHOSPHATE CEMENTS438
7.0 HYDROXYAPATITE4
REFERENCES446
1 Gypsum and Gypsum Products449
1.0 INTRODUCTION449
DIFFERENTIAL SCANNING CALORIMETRY (DSC)450
3.0 THERMOGRAVIMETRIC ANALYSIS (TG)454
4.0 DEHYDRATION OF GYPSUM455
5.0 SIMULTANEOUS TG-DTG-DTA459
6.0 CONVERSION REACTIONS462
6.1 Dihydrate to β-Anhydrite462
6.2Conversion of Soluble to Insoluble Anhydrite467
ANALYSIS (CRTA)467
7.1 CRTA and Kinetic Modeling473
8.0A THREE STEP GYPSUM DEHYDRATION PROCESS477
9.0 INDUSTRIAL APPLICATIONS480
9.1 Portland Cement and Stucco480
9.2 Gypsum–Based Cements482
9.3 Sedimentary Rocks Containing Gypsum484
9.4Quality Control of Commercial Plasters484
9.5 White Coat Plaster487
9.6 Expanding Cement488
REFERENCES488
12 Clay-Based Construction Products491
1.0 INTRODUCTION491
CLAYS AND ACCESSORY MINERALS492
2.1 DTA of Clay Minerals492
2.2 Other Thermal Methods500
3.0 APPLICATIONS508
3.1 Analysis of Brick Clays508
3.2 Thermal Efficiency of Kilns508
3.3 Dark Color of Soils508
3.4 Bloatability of Clays510
3.5 Weathering of Roofing Slates513
3.6 Soil Stabilization514
3.7 Structural Ceramics514
3.8 Solid Waste in Clay Bricks517
3.9 Archaeological Investigations518
4.0 DURABILITY OF CLAY BRICKS519
4.1 Dimensional Changes519
4.2 Saturation Coefficient521
4.3Firing Temperature of Clay Brick521
4.4Brick Particulate Additives for Concrete526
REFERENCES529
13Introduction to Organic Construction Materials531
1.0 INTRODUCTION531
2.0 ADHESIVES AND SEALANTS538
2.1 Adhesives538
2.2 Sealants547
3.0 PAINTS AND COATINGS553
4.0 ASPHALT - BITUMINOUS MATERIALS560
5.0 ROOF COVERING MATERIALS563
5.1 Polymers565
5.2 Membrane Characteristics568
REFERENCES573
14 Sealants and Adhesives579
1.0 INTRODUCTION579
2.0 TEST METHODS580
3.0 APPLICATIONS584
3.1 Sealants584
3.2 Adhesives599
REFERENCES606
15 Roofing Materials611
1.0 INTRODUCTION611
2.0 BITUMINOUS ROOFING MATERIAL612
3.0 SYNTHETIC ROOFING MEMBRANES613
4.0 APPLICATIONS615
16 Paints and Coatings633
1.0 INTRODUCTION633
2.0 PAINTS634
3.0 COATINGS640
3.1 Intumescent Coatings640
3.2 Silicone Coatings645
3.3 Organic Coatings Degradation (Service-Life)647
3.4 Inorganic Coatings649
3.5 Miscellaneous Coatings650
REFERENCES652

xi Contents Index .......................................................................................... 655

Preface

A substance subjected to thermal treatment may undergo physicochemical processes involving weight changes, crystalline transitions, mechanical properties, enthalpy, magnetic susceptibility, optical properties, acoustic properties, etc. Thermal techniques follow such changes, generally as a function of temperature, that could extend from subzero to very high temperatures. Several types of thermal techniques are in use and examples include thermogravimetry, differential thermal analysis, differential scanning calorimetry, thermomechanical analysis, derivative thermogravimetry, dynamic thermal analysis, dielectric analysis, and emanation thermal analysis. A related technique that is extensively applied to investigate inorganic construction materials is called conduction calorimetry which measures the rate of heat changes, as a function of time or temperature.

Thermal analysis techniques have been employed to study various types of inorganic and organic construction materials. They have been applied more extensively to the investigation of inorganic materials. Useful information generated by the use of these techniques includes: characterization, identification of compounds, estimation of materials, kinetics of reactions, mechanisms, synthesis of compounds, quality control of raw materials, rheological changes, glass transitions, and causes leading to the deterioration of materials. Thermal techniques are also used in combination with other techniques such as chemical analysis, x-ray diffraction, infrared analysis, and scanning electron microscopy.

x Preface

There is no book at present that provides a comprehensive treatise on the application of thermal analysis techniques to various types of construction materials. This book comprises sixteen chapters and includes information on almost all important construction materials. Four chapters, Chs. 2, 4, 9 and 13, are devoted to the general introduction of these materials because of the complex nature and behavior of these materials.

The first chapter describes the more common thermoanalytical techniques that are adopted in the study of construction materials. The general principles and types of equipment used are given with typical examples. The described techniques include differential thermal analysis, differential calorimetry, thermogravimetry, thermomechanical analysis, dynamic mechanical analysis, dielectric analysis, and conduction calorimetry.

The physicochemical characteristics of concrete depend on the behavior of the individual components of portland cement as well as on the cement itself. The second chapter provides essential information on cement and cement components so that the information presented in subsequent chapters can easily be followed. In this chapter, the formation of cement, the hydration of individual cement compounds and cement itself, physicochemical processes during the formation of the pastes, the properties of the cement paste, and the durability aspects of concrete are discussed.

The information presented in Ch. 3 clearly demonstrates the extensive applicability of thermal techniques for investigations of raw materials for the manufacture of cement, clinker formation, hydration of cement compounds and cement, the oxide systems of relevance to cement chemistry, and durability processes. Some examples of the usefulness of associated techniques for these investigations are also given

Incorporation of chemical and mineral admixtures in concrete results in many beneficial effects such as enhanced physical and mechanical properties and durability. Many types of admixtures are currently in the market and their effect on concrete is determined by complex factors. Hence, Ch. 4 has been included to describe types of admixtures and their roles in concrete technology. This chapter should serve as an introduction to the subsequent chapters devoted to the application of thermal analysis techniques for the investigation of the role of admixtures in concrete.

The versatility of the thermal analysis techniques such as TG, DTG,

DTA, DSC, and conduction calorimetry for evaluating the role of admixtures in concrete is demonstrated in Chs. 5 through 8. The actions of accelerators, retarding/water-reducing admixtures, superplasticizers and supplementary cementing, and other admixtures are described in Chs. 5, 6,

Preface xi

7, and 8, respectively. Various types of valuable information may be derived by applying these techniques. Examples include: heats of hydration, mechanisms of reactions, composition of the products, cement-admixture interactions, compatibility of admixtures with cement, prediction of some properties, abnormal behavior of concrete, material characterization, development of new admixtures and techniques, and quick assessment of some properties. In many instances, the results obtained by thermal techniques can be related to strength development, microstructure, permeability, and durability aspects in cement paste and concrete. Thermal analysis techniques are shown to be eminently suited to characterize supplementary cementing materials and for determining the potential cementing properties of wastes and byproducts. The relative activities of supplementary materials such as silica fume, slag, pozzolans, etc., from different sources may be quickly assessed by thermal methods.

Portland cement-based concretes are extensively used in the construction industry. Non-portland cement based systems, although not produced to the same extent as portland cement, have found applications especially for repair of concrete structures. Chapter 9, an introduction to non-portland cements, provides a description of the hydration and engineering behaviors of cements such as oxychloride/oxysulfate cements, calcium aluminate cement, portland-calcium aluminate blended cement, phosphate cement, regulated set cement, and gypsum. Chapter 10 provides information on the application of thermal techniques such as DTA, DSC, DTG, TG, and conduction calorimetry to selected groups of rapid setting cements. Studies on the degree of hydration at different temperatures, identification and estimation of products, and heats of hydration are discussed in this chapter.

Gypsum is an essential ingredient in portland cement. Calcined gypsum finds many uses in the construction industry. It is also used as an insulating material. Thermal methods are shown to be applicable to the rapid evaluation of these systems. Chapter 1 deals with the studies on gypsum and α and β forms of CaSO4•½H2O. The effect of environmental conditions on the determination of various forms of calcium sulfate is also given along with the development of recent techniques. A subchapter on the industrial products such as portland cement stucco, gypsum-based cement, sedimentary rocks, plasters, and expanding cement is also included.

One of the first applications of thermal techniques was related to the characterization of clay minerals. Extensive work has been carried out on thermal analysis of clay products. Identification and characterization of clay raw materials and accessory minerals, reactions that occur during the firing xii Preface process, and durability aspects of clay products can be examined conveniently by DTA, TG, TMA, and dilatometry and these aspects are discussed in Ch. 12.

There is a great potential for the application of thermal analysis techniques to study the behavior of organic construction materials such as adhesives, sealants, paints, coatings, asphalts, and roofing materials. Different types of polymers constitute these materials. Chapter 13 is an introduction to the organic construction materials and provides essential information on aspects such as the sources, structure, classification, general characteristics, applications, and durability. Next, Chs. 14, 15, and 16, discuss the application of thermal analysis techniques for studies pertaining to sealants/ adhesives, roofing materials, and paints/coatings, respectively.

Many physical and chemical processes are involved in the degradation of sealants and adhesives. Thermal analysis techniques have been used to characterize polymeric adhesives and sealant formulations and also to study the processes of degradation when they are exposed to natural elements. The application of techniques such as TG, DSC, DTG, Dynamic Mechanical Analysis, Dynamic Mechanical Thermal Analysis, Thermomechanical Analysis, and Dynamic Load Thermomechanical Analysis for such materials has been discussed in Ch. 14.

Although bituminous and modified bituminous roofing materials are well known in the construction industry, several types of synthetic polymers such as PVC, EPDM, KEE, TPO, and polyurethane are also adopted in various applications. Many types of thermal techniques have been applied to investigate glass transition temperatures, vulcanization reactions, oxidation stability, weight, and dimensional, rheological and phase modifications in the roofing material systems. These techniques have also provided useful information on the degradation processes. Chapter 15 provides several examples of the applicability of thermal analysis techniques for investigating the traditional as well as new types of roofing materials.

Thermal analysis techniques also find applications in the study of paints and coatings. Chapter 16 describes the utilization of these techniques for investigations related to characterization, drying phenomenon, decomposition and cross linking, thermal stability, mechanism of decomposition, degree of curing, kinetics of reactions, influence of impurities, differences in crystallinity during pigment formation, heats of reaction or mixing, effects of environmental conditions, and waste utilization.

This comprehensive book containing essential information on the applicability of thermal analysis techniques to evaluate inorganic and

Preface xiii organic materials in construction technology should serve as a useful reference material for the scientist, engineer, construction technologist, architect, manufacturer, and user of construction materials, standardwriting bodies, and analytical chemists.

February 5, 2002V.S. Ramachandran Ottawa, OntarioRalph M. Paroli

James J. Beaudoin Ana H. Delgado

1.0 INTRODUCTION

Thermal analysis has been defined by the International Confederation of Thermal Analysis (ICTA) as a general term which covers a variety of techniques that record the physical and chemical changes occurring in a substance as a function of temperature.[1][2] This term, therefore, encompasses many classical techniques such as thermogravimetry (TG), evolved gas analysis (EGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC), and the modern techniques, such as thermomechanical analysis (TMA) as well as dynamic mechanical analysis (DMA), and dilatometry, just to name a few. The application of thermal analysis to the study of construction materials stems from the fact that they undergo physicochemical changes on heating.

Thermoanalytical Techniques

2Chapter 1 - Thermoanalytical Techniques

2.0 CLASSICAL TECHNIQUES

Ever since the invention of DSC, there has been much confusion over the difference between DTA and DSC. The exact ICTA definition of DTA is a method that monitors the temperature difference existing between a sample and a reference material as a function of time and/or temperature assuming that both sample and reference are subjected to the same environment at a selected heating or cooling rate.[1][2] The plot of ∆T as a function of temperature is termed a DTA curve and endothermic transitions are plotted downward on the y-axis, while temperature (or time) is plotted on the x-axis. DSC, on the other hand, has been defined as a technique that records the energy (in the form of heat) required to yield a zero temperature difference between a substance and a reference, as a function of either temperature or time at a predetermined heating and/or cooling rate, once again assuming that both the sample and the reference material are in the same environment.[1][2] The plot obtained is known as a DSC curve and shows the amount of heat applied as a function of temperature or time. As can be seen from the above definitions, the two techniques are similar, but not the same. The two yield the same thermodynamic data such as enthalpy, entropy, Gibbs’ free energy, and specific heat, as well as kinetic data. It is only the method by which the information is obtained that differentiates the two techniques. A brief history on the development and a comparison of the two techniques are given.*

(Parte 1 de 5)

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