1、THIN REINFORCED CEMENT-BASED PRODUCTS AND CONSTRUCTION SYSTEMS Editor Ashish Dubey American Concrete Institute“ Advancing concrete knowledge S P-224 Thin Reinforced Cement-Based Products and Construction Systems Editor Ashish Dubey American Concret e Ins t tu te“ Advancing conmete knowlei SP-224 Fir
2、st printing, November 2004 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 May 2005. All discussion approved by the Te
3、chnical Activities Committee along with closing remarks by the authors will be published in the September/October 2005 issue of either AC1 Structural Journal or Materials Journal depending on the subject emphasis of the individual paper. The Institute is not responsible for the statements or opinion
4、s 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 by indiv
5、iduals expert in the subject areas of the papers. Copyright O 2004 AMERICAN CONCRETE INSTITUTE P.O. Box 9094 Farmington Hills, Michigan 48333-9094 All rights reserved, including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by any
6、 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. Cover Page Photonraph The Clubhouse at Abu Dhabi - The build
7、ing demonstrates the use of thin cementitious panels as exterior cladding. Photograpli courtesy of Fibrex LLC, Abu Dhabi Printed in the United States of America Editorial production: Lindsay K. Kennedy Library of Congress catalog card number: 20041 14457 ISBN: 0-8703 1-1 59-X PREFAE The use of thin
8、reinforced cementitious products continues to grow rapidly today in a variety of construction applications worldwide. Thin reinforced cementitious products are strong and tough, dimensionally stable, fire resistant, and possess excellent moisture resistance and environmental durability. With the con
9、tinued rapid decline in the use of asbestos fibers as reinforcement in thin cementitious products, several advancements have occurred in the field as a result of the development of new types and forms of reinforcement for thin cementitious products. Also, several advancements have taken place in the
10、 material science and manufacturing methods of cementitious materials for thin reinforced cementitious products. This publication contains the papers originally presented in a symposium on the topic of thin reinforced cementitious products organized by AC1 Committee 549 on Thin Reinforced Cementitio
11、us Products and Ferrocement during the AC1 2003 Spring Convention held in Vancouver, Canada. The symposium explored current state-of-the-art and recent advances in material science, manufacturing methods, and practical applications of thin reinforced cementitious products. The topics covered in this
12、 publication include material science oftextile reinforced concrete, use of textile reinforced concrete for integrated formwork and exterior cladding panels, prestressed thin-sheet concrete products, ultra-high-performance thin precast concrete products, production of concrete tubes by centrifugatio
13、n method, freezing-and-thawing durability of commercial fiber-reinforced cement boards, structural evaluation of cernent- skin sandwich building systems, microwave accelerated curing method for producing precast cementitious products, history of glass fiber-reinforced concrete (GFRC) products, and n
14、iodeling of cement-based laminate composites. The papers presented in this publication have beeu peer reviewed by experts in the field, according to the guidelines established by the American Concrete Institute. The future of thin reinforced cementitious products depends largely on their ability to
15、compete cost effectively with similar products made using other materials such as metals and plastics. For future research and development, this entails understanding and optimizing fiber-reinforced cementitious compositions from a fundamental material science perspective; developing and implementin
16、g the use of cost-effective raw materials, particularly reinforcing fibers and other forms of reinforcement; and developing efficient manufacturing methods to produce thin reinforced cementitious products. Ashish Dubey Editor Chair, ACI Committee 549 Thin Rei forced Cenrentifious Pi-odircts and Ferr
17、ocement iii iv TABLE OF CONTENTS . Preface 111 SP-224-1: GFRC-30 Years of High Fiber Cement Composite Applications Worldwide . 1 by G. T. Gilbert SP-224-2: Towards Prestressed Thin-Sheet Glass Concrete Products 2 1 by G. Vilkner and C. Meyer SP-224-3: Textile Reinforced Concrete: Investigations at D
18、ifferent Levels . 33 by J. Hegger, A. Sherif, O. Bruckermann, and M. Konrad SP-224-4: Textile Reinforced Concrete (TRC) for Integrated Formworks 45 by W. Brameshuher, M. Koster, J. Hegger, S.Voss,T. Gries,M. Barl, H.-W. Reinhardt, and M. Krger SP-226.5: Exterior Cladding Panels as an Application of
19、Textile Reinforced Concrete 55 by J. Hegger, H. Schneider, A. Sherif, M. Molter, and S. Voss SP-224-6: Ultra-High Performance Concrete with Ductility: Design, Prototyping, and Manufacturing of Panels and Boxes 7 1 by D. Zakariasen and V. Perry SP-224-7: New Cement Composites for Thin Structural Prod
20、ucts 89 ,by E. Parant and P. Rossi SP-224-8: Structural Evaluation of Cement Skin Sandwich Building System . 10 1 by Y. Shao, E. Blain-Cosgrove, and B. Robinson SP-224-9: Properties of Short Fiber Reinforced Cement Paste for Concrete Tubes Produced by Centrifugation Method . 1 I3 by D. Hesselbarth a
21、nd J. Kaufmann SP-224- 1 O: Temperature Controlled Microwave Acclerated Curing of Precast by K. C. G. Ong, C. P. Teo, C. H. Shum, L. H. J. Wong, S. T. Tan, and C. T. Tam Ferrocement Secondary Roofing Slabs 1 27 SP-224- 1 I : Freeze-Thaw Durability of Commercial Fiber-Reinforced Cement Board . 145 by
22、 K. G. Kuder and S. P. Shah V SP-224-12: Crack Growth Resistance of Thin Mortar Layers with Hybrid Fiber by L. Sorelli, N. Banthia, and G. A. Plizzari Reinforcement . 161 SP-224-13: Modeling of Cement Based Composite Laminates i 79 by B. Mobasher SP-224-14: Effect of Crack Growth on Overall Mechanic
23、al Properties of Cement Composites . 193 by M. Boulfiza and N. Banthia vi GFRC-30 Years of High Fiber Cement Composite Applications Worldwide by G. T. Gilbert Syxwpsk Thin, fiber reinforced cementitious products offer a useful balance of properties such as strength, toughness, environmental durabili
24、ty, moisture resistance, dimensional stability, fire resistance, aesthetics and ease of handling and installation. For more than 30 years, AR glass fibers have been at the forefront in the development of new applications of such products throughout the World. Glass Fiber Reinforced Concrete GFRC is
25、a thin, cement composite based on AR glass fibers with an excellent strength to weight ratio. Extensive early laboratory work produced a test method for determining long term strength. The validiy of this work has been proven by the large number of buildings clad with GFRC, as well as a vast range o
26、f other GFRC products, used over a this 30 year period. This paper explains the fundamental principles behind GFRC and gives examples of some of its uses. These applications range from high quality, architectural wall panels and decorative elements through to modular buildings down to low cost chann
27、el sections and utility components. New developments and techniques will also be discussed. Keywords; AR glass fibers; AR mats; AR meshes; decorative elements; durability; engineering properties; fiber cement; fiber reinforcement; manufacturing methods; modular buildings; thin cementitious products;
28、 wall panels 1 2 Gilbert Graham T Gilbert, CChem. MRSC is a Chartered Chemist and a Member of the Royal Sociey of Chemistry. He is currently with Vetrotex Cem-FIL, a subsidiary company of the Saint-Gobain Group, one of the Worlds leading suppliers of building materials. Based in the UK, he has worke
29、d on the use of AR Glass fibers as a fibrous reinforcement for cement based composites and concrete for more than 30 years. During this period, he has traveled extensively encompassing all the major European countries as well as the Middle East and North America providing techno-commercial support t
30、o both new and existing manufacturers. He is also a member of the American Concrete Institute, The PrecastPrestressed Institute and the International Glassfibre Reinforced Concrete Association. 1 .O INTRODUCTION Cement based materials have inherent defects such as flaws in the matrix due to shrinkag
31、e and debonding at interfaces. AR glass fibers in this brittle cementitious materials help to enhance the composite toughness and tensile strength by synergistically interacting with the micro cracks that develop when the composite is loaded. The AR glass fibers restrain crack opening and crack grow
32、th by effectively bridging across the micro cracks. The most common form of glass fibers, E-glass, is used as a reinforcing material in resin composites referred to as FRP. However, when E-glass fibers are exposed to portland cement based mixtures, such as mortars or regular concrete, the alkaline n
33、ature of the cementitious mixtures rapidly deteriorates the glass fiber. Because of this, AR glass fibers were developed by intrinsically modifying the chemical composition of the glass fibers such that they are inherently more chemically resistant to the alkaline nature of cementitious matrix. The
34、actual dose rate used will determine the final composite properties with O.6kgku.m. llb/cu.yd being used for plastic shrinkage cracking of regular concrete. However, thin section 12mm 1/2” GFR Concrete will use much higher dose rates ranging from 2-5% of total weight being the normal range. Recently
35、, dose rates as high as 15-18% of continuous filament have been used for newly developed filament wound poles. The exceptional high tensile strength of AR glass fibers imparts tensile properties to the resultant composite as well as improving its toughness and impact strength. Because GFRC has both
36、good tensile and compressive strength as well as being lightweight with good fire properties and low maintenance, it has been used throughout the World in a wide range of applications and these will be highlighted later in this paper. Thin Reinforced Cement-Based Products 3 2.0 AR GLASS FIBERS 2.1 G
37、eneral Data and Fiber Twes In order to make glass fibers resistant to the lime generated during the setting of Portland cement, zirconium is added to the glass mixture composition prior to melting and fiberising the raw materials. The added zirconium becomes part of the glass fiber molecular structu
38、re in the manufacturing process and is not just a protective coating. The minimum zirconium content in the composition for good durability is about 16% by weight. The glass fibers with this zirconium modification are usually referred to as aikaii-resistant glass fibers or AR glass fibers. AR glass f
39、ibers are chemically stable resisting both alkali and acid conditions. Chemical composition of the AR glass fibers is shown in Table 1 and the physical and mechanical properties in Table 2. AR glass fibers for use in concrete are available in three basic forms - discrete chopped strands CS, continuo
40、us rovings and meshes. 2. i. i AR Glass Fiber Discrete Chomed Strands- are used primarily in premix glass fiber reinforced concrete high dose rate and in crack control of concrete low dose rate where the glass is added directly to the cement or concrete slurry. Typically, AR glass fiber CS are avail
41、able in two types, integral and water dispersible. Glass fiber CS are made up of bundles of individual filaments with the typical diameter of these filaments being 12-20 microns. 2.1.2 Inteu-al Chopped Strands- are designed to stay as bundles of filaments through mixing and placing, with as little b
42、reakdown o( the bundle as possible Fig IA. Integral strand bundles can contain as many 400 and as few as 50 filaments. The number of filaments per bundle is usually referred as strand geometry. The diameter of the individual filaments, the number of filaments that are bundled together, and the integ
43、rity of the bundle are the key factors that determine performance characteristics of the strand. The typical length of discrete AR glass fiber strands used in thin-reinforced products ranges between 6 i /Y to 40 1 %”I mrn. The strand geometry, strand length, and glass fiber content all contribute to
44、 the processing characteristics of the composite and its final properties. 2. i .3 Water dispersible Chomed Strands- are designed to disperse quickly into individual strands on contact with water or an aqueous cementitious mixture. These fibers are used in composites where a fine dispersion of indiv
45、idual monofilaments is desired rather than intact fiber bundles. In particular, water dispersible AR glass fibers are commonly used to reduce cracking in concrete, mortars and stucco application and in manufacturing processes that involve cementitious slurries with initial high water content such as
46、 modified Hatschek process or for calcium and sodium silicate applications frequently using the filter-press processes. Typical length of water dispersible AR glass fiber strands used in thin-reinforced cement products ranges between 6 1/47 to 25 i” mm. 2.1.4 Continuous AR Glass Fibers- are availabl
47、e in the form of roving Fig. iB. A roving is an assemblage of several continuous AR glass fiber monofilaments. The 4 Gilbert manner in which the monofilaments are assembled varies and differentiates one roving type from another. Fundamentally, the construction of an AR fiber roving is as follows: Se
48、veral continuous alkali-resistant glass fiber monofilaments are gathered together to form a continuous strand. The typical diameter of the individual alkali-resistant glass fiber monofilaments ranges between 10 to 20 microns. Typically, the number of monofilaments that are gathered together to form
49、a continuous strand ranges between 50 to 400. continuous roving. assembled to form a continuous roving ranges between 20 to1 OO. Several continuous strands as explained above are assembled together to form a Typically, the number of continuous strands that are 2.1.6 Glass Fiber Meshes and Mats- are woven or dipped, non-woven products from assembled glass fiber rovings or strands whilst mats are chopped fibers bonded together with a polymeric coating. Traditionally they were woven products of heavily coated E- glass fiber yarn used mainly in the production
