1、An ACI Technical Publication SYMPOSIUM VOLUME SP-317 Sulfate Attack on Concrete: A Holistic Perspective Editors: Mohamed T. Bassuoni, R. Doug Hooton and Thanos DrimalasSulfate Attack on Concrete: A Holistic Perspective SP-317 Editors: Mohamed T. Bassuoni, R. Doug Hooton and Thanos DrimalasDiscussion
2、 is welcomed for all materials published in this issue and will appear ten months from this journals date if the discussion is received within four months of the papers print publication. Discussion of material received after specified dates will be considered individually for publication or private
3、 response. ACI Standards published in ACI Journals for public comment have discussion due dates printed with the Standard. The Institute is not responsible for the statements or opinions expressed in its publications. Institute publications are not able to, nor intended to, supplant individual train
4、ing, 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 individuals expert in the subject areas of the papers. Copyright 2017 AMERICAN CONCRETE INSTITUTE 38800 Country Club Dr.
5、 Farmington Hills, Michigan 48331 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 electronic or mechanical device, printed or written or oral, or recording for sound or visual reproduction or fo
6、r 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 Editorial production: Aimee Kahaian ISBN-13: 978-1-945487-67-5 First printing, June 2017Preface The papers presented in this volume w
7、ere included in a three-part session sponsored by ACI Committee 201, Durability of Concrete, about sulfate attack on concrete at the ACI Convention in Philadelphia, PA, on October 23-24, 2016. In line with the practice and requirements of the American Concrete Institute, peer review, followed by app
8、ropriate response and revision by authors, has been used. Deterioration of concrete due to sulfate attack is a complex process characterized by multiple damage manifestations including volumetric expansion, cracking, spalling, softening, and in some cases mushiness. Sulfate attack can generally be c
9、lassified as internal or external to the cementitious matrix, and the underlying damage modes can be chemical or physical. The scope of papers involves a multitude of theoretical and experimental aspects of different forms of sulfate attack. Readers are urged to critically evaluate the work presente
10、d herein, in the light of the large body of knowledge and scientific literature on this durability topic. We dedicate this volume of papers to the memory of Prof. Robert L. Day, past chairman of Canadian Standards Association (CSA) Committee A23.1/A23.2 (Concrete Materials and Construction), for his
11、 invaluable contributions to the field of durability of concrete. The editors sincerely thank all the presenters in this session and authors of the articles included in this SP, as well as the reviewers for their objective assessment of the papers. Their technical contributions provided a holistic p
12、erspective of sulfate attack on concrete. Mohamed T. Bassuoni, Chairman and Editor R. Doug Hooton, Co-chairman and Co-editor Thano Drimalas, Co-chairman and Co-editorTABLE OF CONTENTS SP-3171 Criteria for Concrete Mixtures Resistant to Chemical Sulfate Attack 1.1 Authors: Karthik H. Obla and Colin L
13、. Lobo SP-3172 Sulfate Resistance of Ternary Blend Concretes: Influence of Binder Composition on Performance .2.1 Authors: R. Brett Holland, Kimberly E. Kurtis, Lawrence F. Kahn SP-3173 Chemical and Mechanical Characterization of Damage Evolution in Concrete Due to External Sulfate Attack .3.1 Autho
14、rs: A. Bonakdar and B. Mobasher SP-3174 Performance of Alternative Binders in Sulfate Environments 4.1 Authors: L.E. Burris and K.E. Kurtis SP-3175 Durability of Two-Stage (Pre-Placed Aggregate) Concrete to Sulfate Attack 5.1 Authors: M. F. Najjar, A. M. Soliman, T. M. Azabi and M. L. Nehdi SP-3176
15、Efficacy of Composite-Strengthening on Axial Capacity of Concrete Subjected to Sulfate-Induced Damage 6.1 Authors: Yongcheng Ji and Yail J. Kim SP-3177 Criteria for Selecting Mixtures Resistant to Physical Salt Attack 7.1 Authors: Karthik H. Obla and Robert C. ONeill SP-3178 Efficacy of Ultrasonic P
16、ulse Velocity Testing to Assess Sulfate-Degraded Concrete 8.1 Authors: Julie Ann Hartell, Andrew J. Boyd, Patrice Rivard SP-3179 The Effects of Supplementary Cementitious Materials and Exposure Temperature on External Sulfate Attack 9.1 Authors: Ashlee Allison and Michael D.A. Thomas SP-31710 Sulfat
17、e Resistance of Mortar Bars in Calcium, Magnesium, and Sodium Sulfate Using A Vacuum Impregnation Technique 10.1 Authors: Federico M. Aguayo, Thano Drimalas, Kevin J. FolliardSP-3171 1.1 Criteria for Concrete Mixtures Resistant to Chemical Sulfate Attack Karthik H. Obla and Colin L. Lobo SYNOPSIS: T
18、his paper presents research on the sulfate resistance of concrete mixtures as it relates to ACI 318 Code requirements for sulfate resistance. The study evaluates the provisions of ACI 318 for various concrete mixtures containing sulfate resisting portland cements and supplementary cementitious mater
19、ials with w/cm varying between 0.40 and 0.60. The sulfate resistance of concrete mixtures was evaluated using prolonged exposure in a concentrated sulfate solution in accordance with USBR Test 4908. The results on the concrete evaluation reveal that the ACI requirements are considerably conservative
20、 for most concrete mixtures that contain a sulfate resisting cementitious system with supplementary cementitious materials. Sulfate resisting portland cements did not perform as well in the associated exposure class defined in ACI 318. While a performance-based alternative to the requirement for a m
21、aximum w/cm was attempted, no clear criteria could be achieved. The paper proposes alternative criteria to those in ACI 318 for sulfate resistance based on the performance of concrete mixtures evaluated in this study. KEYWORDS: ACI 318, chemical sulfate attack, Code requirements, specifications, sul
22、fate resistance Karthik H. Obla and Colin L. Lobo 1.2 AUTHOR BIOGRAPHY: Karthik H. Obla, FACI, is Vice President of Technical Services at NRMCA, Silver Spring, MD. He serves on several ACI committees, including 201, Durability of Concrete; 211, Proportioning Concrete Mixtures; 214, Evaluation of Res
23、ults of Tests Used to Determine the Strength of Concrete; 232, Fly Ash in Concrete (Past Chair); 236, Material Science of Concrete; 240, Natural Pozzolans; 329, Performance Criteria for Ready Mixed Concrete; 365, Service Life Prediction; 555, Concrete with Recycled Materials; and C601-B, Concrete Qu
24、ality Technical Manager. He is a winner of ACIs Young Professional Achievement Award. He served as Vice-President and President for the ACI San Antonio Chapter. He received his BS in Civil Engineering from IIT (BHU) Varanasi, India and his MS and PhD in Civil Engineering from the University of Michi
25、gan, Ann Arbor, and is a licensed engineer in the state of Maryland. Colin L. Lobo, FACI, is Senior Vice President of the Engineering Division at NRMCA, Silver Spring, MD. He serves on several ACI committees, including 132, Responsibility in Concrete Construction; 211, Proportioning Concrete Mixture
26、s; 214, Evaluation of Results of Tests Used to Determine the Strength of Concrete; 228, Nondestructive Testing of Concrete; 301, Specifications for Concrete; 318, Structural Concrete Building Code; and 329, Performance Criteria for Ready Mixed Concrete, and E701, Materials for Concrete Construction.
27、 He received his BE in civil engineering from Mysore University, India; his MS from Northeastern University, Boston, MA; and his PhD from Purdue University, West Lafayette, IN. He is a licensed engineer in the state of Maryland. INTRODUCTION Exposure of concrete members to water-soluble sulfates fro
28、m external sources can be a significant cause of deterioration. This type of durability problem is typically prevalent where higher sulfate concentrations are present in soil or water in contact with concrete. It can also be an issue in facilities that generate sulfate bearing solutions that will co
29、me in contact with concrete. There are three types of phenomenon observed when concrete members are exposed to an external source of sulfates 1 chemical sulfate attack 2 ; physical sulfate attack resulting from crystallization of some salts of sulfate 3, 4, 5 ; and thaumasite formation when concrete
30、 mixtures contain finely divided carbonates 6, 7 . This paper is limited to chemical sulfate attack, often referred to as classical sulfate attack. Chemical sulfate attack is governed by two factors 1, 8, 9 : 1. Type and characteristics of cementitious materials Increased quantity of tri-calcium alu
31、minate phase, C 3A, in portland cement decreases its sulfate resistance. Aluminate phases in some supplementary cementitious materials (SCM), such as in some Class C fly ash 10 , or higher alumina content in slag cement 11 , can contribute to sulfate attack. 2. Permeability of concrete Water-soluble
32、 sulfates penetrate concrete by a combination of capillary sorption and diffusion. Concrete mixtures with a low w/cm and containing SCM reduce the rate of penetration of sulfates into the concrete. The ACI 318 Building Code, ACI 318-14 12 , limits its durability provisions to chemical sulfate resist
33、ance in the sulfate exposure category. It defines sulfate exposure classes based on the concentration of sulfate in soil or water concrete members will be exposed to. The requirements for concrete mixtures that will be exposed to these exposure classes are summarized in Table 1. ACI 318-14 also perm
34、its a cementitious materials combination that has been qualified when tested by ASTM C1012 13with expansion criteria listed in Table 1. Service records of acceptable performance of concrete mixtures containing SCM are also permitted in lieu of ASTM C1012 tests. The objective of this research project
35、 was to evaluate the current requirements for sulfate resistance in ACI 318 and to evaluate whether a rapid index test that provides an indicator of the permeability of concrete could be proposed as an alternative to the maximum w/cm. The maximum w/cm limit is invoked as a prescriptive requirement t
36、o reduce the permeability of concrete that controls the rate of penetration of water-soluble sulfates from external sources into the concrete. Besides w/cm, however, the permeability of concrete is also impacted by the composition of the cementitious materials used in the mixture and this benefit fr
37、om using SCMs is not accounted for in the current provisions. The sulfate resistance of concrete was evaluated by a long-term immersion test used by the US Bureau of Reclamation (USBR) in their research work on sulfate resistance. A modified version of USBR 4908 14test was used Criteria for Concrete
38、 Mixtures Resistant to Chemical Sulfate Attack 1.3 in this study. The level of sulfate resistance of concrete in USBR 4908 was related to the performance of cementitious materials in ASTM C1012 and other mixture characteristics. Based on these comparisons alternative requirements for chemical sulfat
39、e resistance are proposed. MATERIALS AND MIXTURES The following materials were used: ASTM C150 13Type I portland cement (PC-I) with C 3A = 12%; ASTM C150 Type II portland cement (PC-II) with C 3A = 8%; ASTM C150 Type V portland cement (PC V-1) with C 3A = 3%, ASTM C150 Type V portland cement (PC V-2
40、) with C 3A = 5%, ASTM C618 15Class F fly ash (FA) CaO = 0.7% ASTM C989 15Grade 120 Slag Cement Al 2O 3 = 11.8% ASTM C778 13standard graded sand for C1012 tests ASTM C33 15natural sand, fineness modulus 2.88 ASTM C33 No. 57 crushed stone coarse aggregate ASTM C494 15Type A polycarboxylate-based wate
41、r reducing admixture and Type F polycarboxylate-based high range water reducing admixture ASTM C1012 was conducted on mortar mixtures with selected combinations of cementitious materials as indicated in Table 2. Twenty two non air-entrained concrete mixtures were made with ASTM C150 Types I, II and
42、V portland cements, varying quantities of slag cement and Class F fly ash, and with w/cm varying between 0.40 and 0.60. The mixtures were evaluated in two separate series. Mixture parameters were selected for different levels of sulfate resistance and to attempt to characterize mixture performance w
43、ithin the four ACI 318 exposure classes for sulfate resistance. Mixture designations were provided to denote the type of mixture: “w/cm; SCM type; SCM quantity: and portland cement type”. Mixtures with only portland cement are denoted with “PC”. Mixture designations and parameters are provided in Ta
44、ble 3. TEST PROCEDURES Several cementitious material combinations were tested for sulfate resistance in accordance with ASTM C1012. Mortar bars were immersed in 5% sodium sulfate solution after achieving the minimum strength required by the test method. This method uses a fixed w/cm of 0.485 and its
45、 purpose is to evaluate the cementitious materials for sulfate resistance. Expansion criteria in ACI 318 extend to 18 months for the more severe exposure class. In this study, the duration of immersion in sulfate solution was extended to 36 months. Mixture parameters and test results for ASTM C1012
46、are provided in Table 2. The concrete mixtures were mixed in a revolving drum laboratory mixer in accordance with ASTM C192 15 . A dosage of 3 oz/cwt. (195 mL/100 kg) of the Type A water-reducing admixture was used for all concrete mixtures. The dosage of the Type F high-range water-reducing admixtu
47、re was varied to attain a target slump between 4 and 7 in. (100 and 175 mm). Fresh concrete was tested for slump in accordance with ASTM C143 15 , temperature in accordance with ASTM C1064 15 , air content by the pressure method in accordance with ASTM C231 15 , and density in accordance with ASTM C
48、138 15 . The gravimetric air content was also calculated in accordance with ASTM C138. Compressive strength of test specimens from the concrete mixtures was tested in accordance with ASTM C39 15 . The strength reported is the average of two 4 8 in. (100 200 mm) cylindrical specimens at an age of 28
49、days. From the concrete mixtures, samples were prepared to measure the transport properties of concrete mixtures. Only results of the rapid chloride permeability tests, ASTM C1202 15 , are reported here. For these tests 4 8 in. (100 200 mm) cylindrical specimens were cast. Specimens were subjected to three curing procedures and durations: Accelerated curing, in accordance with ASTM C1202, and tested at an age of 28 days; Moist cured and tested at an age of 56 days; and Karthik H. Obla and Colin L. Lobo 1.4 Moist cured and tested at an
