《ACI-SP-156-1999.pdf》由会员分享,可在线阅读,更多相关《ACI-SP-156-1999.pdf(219页珍藏版)》请在三一文库上搜索。
1、A C 1 SP-L5b 95 0bb2949 052Y890 2T INT AC FRACT AND EDITORS Oral Buyukozturk Methi Wecharatana SPI1 56 COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Servic
2、es I A C 1 SP-15b 95 m Obb2949 0524891 134 m EDITORS Oral Buyukozturk Methi Wecharatana SPI1 56 COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services A C
3、1 SP-156 95 = Obb2949 0524892 070 DISCUSSION of individual papers in this symposium may be submitted in accordance with general requirements of the AC1 Publication Policy to AC1 headquarters at the address given below. Closing date for submission of discussion is January 1, 1996. All discussion appr
4、oved by the Technical Activities Committee along with closing remarks by the authors will be published in the May/June 1996 issue of either AC1 Structural Journal or AC1 Materials Journal depending on the subject emphasis of the individual paper. The Institute is not responsible for the statements o
5、r opinions expressed in its publications. Institute publications are not able to, nor intended to, supplant individual training, responsibility, or judgment of the user, or the supplier, of the information presented. The papers in this volume have been reviewed under Institute publication procedures
6、 by individuals expert in the subject areas of the papers. Copyright O 1995 AMERICAN CONCRETE INSTITUTE P.O. Box 19150, Redford Station Detroit, Michigan 48219 All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo proces
7、s, or by any electronic or mechanical device, printed or written or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. Printed in the United States of America Editoria
8、l production Victoria Lunick Cover design Steven Kronenberg Library of Congress catalog card number 95-77208 COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling
9、Services A C 1 SP-156 95 Ob62949 0524893 TO7 PREFACE Interfaces, such as mortar-aggregate interfaces and cement matrix-fiber interfaces, affect the mechanical behavior of concrete composites. Signifi- cant considerations in understanding the mechanical behavior of concrete are the nature of the defo
10、rmation and failure of these interfaces and the interaction between the constituent elements of the composite. Develop- ment of advanced concrete materials with improved toughness and durabil- ity requires a fundamental understanding of the behavior of the interfaces which are intrinsic to the concr
11、ete composite. Therefore, there is a need to characterize the interfacial behavior and to study the role of the interfaces on the global material behavior as a basis for the development of high per- formance cementitious materials. As part of its activities, Committee 446, Fracture Mechanics, sponso
12、red a technical session on interface fracture and bond at the Vancouver Spring convention of the American Concrete Institute, March 28-April 2, 1993. This book is a collection of papers from that session and some additional papers. The papers were reviewed by members of the AC1 committee, as well as
13、 other experts in the field. These original, reviewed, and revised papers constitute this AC1 Special Publication. It is hoped that the publi- cation w i l l contribute to the understanding of fundamental issues and stim- ulate further interaction between researchers on this important topic. The edi
14、tors gratefully acknowledge the contribution of members of the AC1 Committee 446, the reviewers, the authors, and the staff of AC1 who have made this volume a timely contribution. Oral Buyukozturk and Methi Wecharatana AC1 Committee 446 iii COPYRIGHT ACI International (American Concrete Institute) L
15、icensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services A C 1 SP-256 95 W 0662749 0524894 943 AC1 Committee 446 FRACTURE MFCHANCIS Vellore S. Gopalaratnam Walter H. Gerstle Chairman Farhad Ansari Zdenk P. Bahnt Oral
16、 Buyukozturk Ignacio Carol Luigi Cedolin Vladimir Cervenka David Darwin Jarmila Davies Manuel Elices Rolf Eligehausen Shu-Jin Fang Pietro G. Gambarova Ravindra Gemi Toshiaki Hasegawa Neil M. Hawkins Hideyuki Horii Anthony R. Ingraffea Jeremy Isenberg Yeou-Sheng Jenq Christopher K. hung Victor C. Li
17、Feng-Bao Lin Jacky Mazars Steven L. McCabe Christian Meyer Richard A. Miller Sidney Mindess Antoine E. Naaman C. Dean Norman Josko Ozbolt Secretary Philip C. Perdikaris Phillip A. Pfeiffer Gill Pijaudier-Cabot Pere C. Prat Jan G. Rots Victor E. Saouma Surendra P. Shah Robert L . Sierakowski Wimal Su
18、aris Stuart E. Swartz Mazen R. Tabbara Tatsuya Tsubaki Cumaras Vipulanandan Methi Wecharatana Yunping Xi iv COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling S
19、ervices A C 1 SP-1.56 95 Ob62949 0524895 8T CONTENTS . PREFACE . 1 1 1 MECHANICAL PROPERTIES OF THE INTERFACIAL TRANSITION ZONE: A REVIEW byS.Mindess . 1 SOFTENING SLIP AND SIZE EFFECT IN BOND FRACTURE by A. P. Baiant and R. Desmorat . 11 FRACTURE AND INTERNAL CRACKING OF HIGH-STRENGTH CONCRETE UNDE
20、R AXIAL COMPRESSION by L. R. Taerwe 25 EXPERIMENTAL STUDIES AND MODELING OF THE CONCRETE/ROCK INTERFACE by J. Wang and A. K. Maji 45 THE ROLE OF INTERFACIAL FRACTURE TOUGHNESS IN CRACKING BEHAVIOR OF HIGH-STRENGTH CONCRETE by K. M. Lee, O. Buyukozturk, and Y. Kitsutaka 69 A LATTICE APPROACH FOR ANAL
21、YZING STEEL-CONCRETE BOND-SLIP-LAYER FRACTURE by A. Vervuurt and J. G. M. Van Mier . 85 FRACTURE MECHANICS ANALYSIS OF BOND BEHAVIOUR UNDER DYNAMIC LOADING by C. Yan and S. Mindess . 107 PREDICTION AND VERIFICATION OF INTERFACE DEBONDING FOR FIBER REINFORCED CEMENTITIOUS MATERIAL by S. H. Li, S. P.
22、Shah, Z. Li, and T. Mura 125 V COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services A C 1 SP-156 95 m 0662749 0524896 Lb EFFECI OF LATERAL STRESS ON THE
23、DEBONDING AND PULLOUT OF STEEL FIBERS I N A CEMENTITIOUS MATRIX by C. K. Y. hung and Y. Geng 153 FLUORESCENCE MICROSCOPIC STUDY OF FRACTURE PROCESS OF THE INTERFACIAL ZONE BETWEEN A STEEL FIBER AND THE CEMENTITIOUS MATRIX UNDER PULLOUT LOADING by M. Kawamura and S. I, Igarashi 173 THE INFLUENCE OF S
24、ILICA FUME ON THE STRENGTH OF by C. Perry and J. E. Gillot . 191 THE CEMENT-AGGREGATE BOND SI (Metric) TABLES .213 INDEX 215 vi COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by In
25、formation Handling Services A C 1 SP-LSb 95 0bb2949 0524897 652 SP 156-1 Mechanical Properties of the Interfacial Transition Zone: A Review by S. Mindess Svnois; The mechanical properties of the cement-aggregate bond are reviewed, with particular reference to the inherent difficulties in determining
26、 these properties. The properties that are determined experimentally appear to be largely artifacts of the specimen preparation and the test procedures. In particular, bleeding effects, the roughness of the rock surface, and the heterogeneity of the interfacial region make it very difficult to compa
27、re experimental results amongst the different investigations that are found in the literature. It is concluded that we are stiii far from being able to make useful measurements of the properties of the cement-aggregate interfacial zone. We cannot, therefore, yet try to control the properties of conc
28、rete by systematidy altering the nature of the interfaciai region. Kevwords: Aggregates; bleeding (concrete); bonding; cements; fracture properties; hardness; interface; mechanical properties; specimens; strength; toughness 1 COPYRIGHT ACI International (American Concrete Institute) Licensed by Info
29、rmation Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services A C 1 SP-156 95 = 0662749 0524898 599 2 Mindess AC1 Feilow Sidney Mindess is a Professor in the Department of Civil Engineering at the University of British Columbia. He is a
30、 member of AC1 Committee 370 - Short T e r m and Vibratory Load E f f e c t s , and of ACI Committee 446 - F r a c t u r e Mechanics. He is also a member of the Co- ordination commi#eeof RILEM. It is now commonplace to consider concrete as a material coI1sisting of t h r e e phases: the hardened cem
31、ent paste (hcp), the - , and the transition zone 0 between the hcp and the aggregate particles. In fact, of course, there are a number of other interkes within modern concrete, including those between i) thevariousphasesinthehcp U) the hcp and anhydrous cement s iii) the hcp and pozzolanic additions
32、 or mineral fillers. Ali of these interfaces are important in determuiin * * g the mechanical properties of the concrete. This is particularly the case as we move from normal strength concrete, in which the properties of the hcp largeiy control the concrete properties, t o high strength concrete, in
33、 which the composite behaviour of the concrete must be considered. Clearly, the strength of concrete must depend upon the intrinsic streigth of the hcp (and possibly of the aggregate), and upon the strength of the bond between the hcp and the aggregate. Unfortunately, it has s o far not been possibl
34、e to determine, in a meaningfd way, the bond strengths between the various phases in concrete, and consequently it has not been possible to quantify the effect of the properties of the iTZ on the properties of concrete. It is generaily assumed that the TZ is the “weak l i n k “ in normai strength co
35、ncrete. Thus, the focus of this review is on the ITZ, and in particuiar, on the difficulties that arise when trying to measure its mechicai properties. Unfortunately, here are no test methods specified in any national standards dealing with the propertie3 (or even the extent) of the ITZ, and so one
36、is left with trying to draw conclusions f r o m the disparate COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services A C 1 SP-156 95 m 0bb2949 0524899 425
37、m Interface Fracture and Bond 3 oollection of experimentai studies that have been repored in the literature. Since there has been virtually no work a t aii on the other intedaces mentioned above, they wil not be discussed in this review. HOW D T H E R O P E R OF THEIlX AFFECT THE MECHANICAL PROPERTE
38、S OF CONCRETE? For the purposes of this review, the precise nature of the composition and morphology of the ITZ is not very important; what we know of this zone has, in any event, been reviewed extensively in recent years (e.g. 1 - 9 ) . It is sufficient to note that the thickness of the IlZ is gene
39、raiiy taken to be about 50 pm, with the major differences from the bulk hcp occurring within about the first 20 pm from the physical interface. We must also recognize the extent of the I T Z . while it is oniy 50 pm thick, Diamond et al. (10) have shown that, in normal concrete, the average minimum
40、spacing between adjacent aggregate particles is oniy about 75-100 pm. Thus, a reiatively large proportion of the hcp lies within the ITZ. While it is generaiiy accepted that increasing the cement-aggregate bond strength will lead to an increase in the concrete strength, the experimental evidence for
41、 this is not consistent. A number of studies have shown that, in going from “no bond“ to “perfect bond“ (insofar as either case can be simulated experimentally) strength increases have been in the range of 15% to 4096, with increases in tensile or flexural strength being higher than the increases in
42、 compressive strength. For instance, Alexander and Toplm (11,12), based on a regression analysis of the data then available to them, developed a relationship of the form o = bo + b,ml + b2m2 where o = concrete strength (compression or flexure) bo,bl,b2 = linear regression coefficients = 480, 2.08, 1
43、.02, respectively, for compression = 290, 0.318, 0.162, respectively, for flexure = flexural strength of the paste and of the cement- ml,m2 aggregate bond, respectively, From these regression coefficients, it may be seen that a change in the strength of the paste has about twice as much effect in th
44、e concrete strength as does a change in the bond strength. Similar results were reported by Darwin and Slate (1 3 ) . COPYRIGHT ACI International (American Concrete Institute) Licensed by Information Handling Services COPYRIGHT ACI International (American Concrete Institute) Licensed by Information
45、Handling Services A C 1 SP-L5b 95 Obb2949 0524900 T77 4 Mindess other investigations, however, have yielded different results. For insiance, Chen and Wang (14) showed that an improvement in cement-aggregate bond strength would significantly increase the tensile strength, and to a lesser extent the c
46、ompressive strength, of concrete. Similar results were obtained by Wu et al. (15) and Wu and Zhan (16). One can only assume that the differences between these results and those referred to above (11- 13) are due to differences in test techniques. Results of numerical simulations (17) have also shown
47、 that changing the bond strength should increase the tensile and flexural strengths, but should have little effect on the compressive strength. On the other hand, a numerical study by Schlangen and van Mer (18) showed that “the specimen strength is mainly governed by the matrix strength“. Thus, “num
48、erical“ concrete appears to be at least as inconsistent with regard to bond strength as does “reai“ concrete! RELATIONSIIIP BETWEEN SPECIMEN PREPARATON AND MEASUREMENT OF INTERFACIAL MECHANICAL PROPERTIES The inconsistencies in the effects of bond strength on the mechanical properties of concrete ap
49、pear to be due t o inconsistencies in the measurements of the properties of the IT2 or of the cement-aggregate bond. There are a number of reasons for this: 1. It is not possible to make direct tests of the strength of the materiai in the TZ, because it is not possible to isolate this material, which is only about 50 pm thick. Moreover, the ITZ is itself variable in its composition, and thus its mechanical properties must also vary from point to point, as shown by the microhardness data that have been reported (19-20). These data indicate that the weakest part of th
链接地址:https://www.31doc.com/p-3729883.html