嗫?暁雲?
混凝土引剂试验报告 工程编号: 工程名 委托编号 委托单位 试验编号 施工单位 委托期 工程部位 试验日期 生产厂 出厂日期 型号、
掺量 % 取样人 见证单位 见证人 执行标
检测项目 标准要求 检
密度 g/mL
装 细度 %
pH值 订
含气量 %
线 减水率 %
泌水率
初凝
凝结
终凝
3d
抗压强度
28d
28天
200次
对钢
氨释
检测
主检人: 审核人: 批准人:
检测单位(公章) 本报告复制件无原检测单位盖章无效;对检测结果若有异议，限收到报告十五日向测单位提出。 理(建设单位)
表B4.06.03 81
C233混凝土引气剂检测标准
Designation:C 233–07
Standard Test Method for
Air-Entraining Admixtures for Concrete 1
This standard is issued under the ?xeddesignation C 233; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e ) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.
1. Scope*
1.1This test method covers the testing of materials pro-posed for use as air-entraining admixtures in the ?eld.
1.2The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information purposes only.
1.3This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.
1.4The text of this test method references notes and footnotes which provide explanatory material. These notes and footnotes (excludingthose in tables and ?gures)shall not be considered as requirements of the standard.
2. Referenced Documents 2.1ASTM Standards:2
C 33Speci?cationfor Concrete Aggregates
C 39/C39M Test Method for Compressive Strength of Cy-lindrical Concrete Specimens
C 78Test Method for Flexural Strength of Concrete (UsingSimple Beam with Third-Point Loading)
C 136Test Method for Sieve Analysis of Fine and Coarse Aggregates
C 143/C143M Test Method for Slump of Hydraulic-Cement Concrete
C 150Speci?cationfor Portland Cement
C 157/C157M Test Method for Length Change of Hard-ened Hydraulic-Cement Mortar and Concrete
C 172Practice for Sampling Freshly Mixed Concrete
C 173/C173M Test Method for Air Content of Freshly Mixed Concrete by the V olumetric Method
This test method is under the jurisdiction of ASTM Committee C09on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.23on Chemical Admixtures.
Current edition approved July 15, 2007. Published August 2007. Originally approved in 1949. Last previous edition approved in 2004as C 233–04. 2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org.For Annual Book of ASTM Standards volume information, refer to the standard’sDocument Summary page on the ASTM website.
1
C 185Test Method for Air Content of Hydraulic Cement Mortar
C 192/C192M Practice for Making and Curing Concrete Test Specimens in the Laboratory
C 231Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method
C 232Test Methods for Bleeding of Concrete
C 260Speci?cationfor Air-Entraining Admixtures for Con-crete
C 403/C403M Test Method for Time of Setting of Concrete Mixtures by Penetration Resistance
C 666/C666M Test Method for Resistance of Concrete to Rapid Freezing and Thawing
C 670Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials D 75Practice for Sampling Aggregates D 1193Speci?cationfor Reagent Water
E 70Test Method for pH of Aqueous Solutions With the Glass Electrode 2.2ACI Standards:
ACI 211.1Recommended Practice for Selecting Propor-tions for Normal, Heavyweight, and Mass Concrete 33. Signi?canceand Use
3.1This test method is used to develop data for comparison with the requirements of Speci?cationC 260. These tests are based on arbitrary stipulations permitting highly standardized testing in the laboratory, and are not intended to simulate actual job conditions.
4. Materials
4.1Cement —Thecement used in any series of tests shall be either the cement proposed for speci?cwork in accordance with 4.4, a Type I or Type II cement conforming to Speci?ca-tion C 150, or a blend of two or more cements, in equal parts. Each cement of the blend shall conform to the requirements of either Type I or Type II, Speci?cationC 150. If a blend of cements is used, it shall be a combination which produces an
American Concrete Institute Manual of Concrete Practice, Part 1, pp. 211-1to 211-38(1993).
3
*ASummary of Changes section appears at the end of this standard.
Copyright ?ASTM International, 100Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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air content of less than 10%when tested in accordance with Test Method C 185(Note 4).
4.2Aggregates —Exceptwhen tests are made in accordance with 4.4, using the aggregates proposed for speci?cwork, the ?neand coarse aggregates used in any series of tests shall come from single lots of well-graded, sound materials that conform to the requirements of Speci?cationC 33, except that the grading of the aggregates shall conform to the following requirements:
4.2.1Fine Aggregate Grading —The?neaggregate shall meet the requirements for the ?neaggregate in Speci?cationC 33.
4.2.2Coarse Aggregate Grading —Thecoarse aggregate grading shall meet the Size 57grading requirements of Speci?cationC 33.
N OTE 1—Takecare in loading and delivery to avoid segregation.
Sieve 37.5-mm 25.0-mm 12.5-mm 4.75-mm 2.36-mm
Speci?cationC 33, No. 57
Percent Passing
10095to 10025to 600to 100to 5
Maximum variation from
average/passing
001.04.04.01.0
N OTE 3—Allof the results required for demonstrating compliance under this speci?cationare dependent on the uniformity of the aggregate samples prepared and used. Careful, skilled and well-supervised work is essential.
4.2.3The coarse aggregate used for the reference concrete and test concretes shall be essentially the same. Provide sufficient coarse aggregate for the reference concrete, the test concrete, and for the grading analysis. Concrete consists of one reference concrete and as many test admixture-containing concretes as are intended to be compared.
4.2.3.1Prepare required quantities of coarse aggregate as follows:Fill tared containers, one for sieve analysis, one for a batch of reference concrete, and one for a batch of test concrete, to the required mass from the aggregate stockpile (SeeNote 2). Accomplish this by placing equal quantities into each container, successively, and repeat the procedure until all the containers have their required mass (SeeNote 2).
N OTE 2—Seethe Appendix of Practice D 75, Sampling from Stock-piles, and the section on Sampling Aggregates in the Manual of Aggregate and Concrete Testing 4for guidance on procedures for sampling from stockpiles.
4.3Reference Admixture —Forthis test method, unless oth-erwise requested by the purchaser, the reference admixture used in the concrete mixture speci?edin Section 4shall be “neutralizedVinsol resin.”5
4.4Materials for Tests for Speci?cUses —Whenit is desired to test an air-entraining admixture for use in speci?cwork, the cement and aggregates used shall be representative of those proposed for use in the work, and the concrete mixtures shall be designed to have the cement content speci?edfor use in the work (Note 4). If the maximum size of coarse aggregate is greater than 25.0mm (1in.), the freshly mixed concrete shall be screened over a 25.0-mm (1-in.)sieve prior to fabricating the test specimens in accordance with the wet sieving proce-dure described in Practice C 172.
4.5Preparation and Weighing —Allmaterials shall be pre-pared and all weighings shall be made as prescribed in Practice C 192/C192M .
N OTE 4—Itis recommended that whenever practicable, tests be made in accordance with 4.4using the cement and pozzolanic or chemical admixtures, if any, proposed for speci?cwork.
4.2.4Perform sieve analysis on the coarse aggregate sample prepared in 4.2.3.1by Test Method C 136. Discard any set for which the sample does not comply with Size 57. Average test results for samples that comply with Size 57for each sieve size. Discard any set for which the sample deviates from this average by more than the amount shown in column 3. Continue the process of preparation, testing and averaging until sufficient sets of aggregate within tolerance are obtained.
5. Concrete Mixtures
5.1Proportions —UsingACI 211.1, all concrete shall be proportioned to conform to the following requirements:
5.1.1The cement content shall be 30763kg/m3(51765lb/yd3) except when tests are being made for speci?cuses (see4.4).
5.1.2The ?rsttrial mixture shall contain the amount of coarse aggregate shown in Table 6.3.6of ACI 211.1for the maximum size of aggregate and for the ?nenessmodulus of the sand being used.
Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards , V ol 04.02.
4
The sole source of supply of Vinsol resin known to the committee at this time is Hercules Inc., Wilmington, DE. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, 1which you may attend. Neutralization may be accomplished by treating 100parts of the Vinsol resin with 9to 15parts of NaOH by weight. In an aqueous solution, the ratio of reagent water (SeeSpeci?cationD 1193) to the resinate shall not exceed 12:1by
weight.
5
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N OTE 5—Thevolumes of coarse aggregate recommended in ACI 211.1are intended to ensure workable mixtures with the least favorable combinations of aggregate likely to be used. It is suggested, therefore, that for a closer approximation of the proportions required for this test, the recommended values in ACI 211.1be multiplied by 1.07for the ?rsttrial mixture.
5.1.3The air content used in the computation of proportions for all concrete shall be 5.5%except where the admixture under test is for use in speci?cwork (see4.4). In this case the air content used in selecting proportions shall be the median of the range to be permitted in the work. If lightweight aggregates are be used in speci?cwork, the unit weight of concrete used in selecting proportions shall be the median of the range permitted in the work.
5.1.4The water content and sand content shall be adjusted to obtain a slump of 90615mm (31?261?2in.). The workability of the concrete mixture shall be suitable for consolidation by hand rodding and the concrete mixture shall have the minimum water content possible. These conditions shall be achieved by ?naladjustments in the proportion of ?neaggregate to total aggregate, in the amount of total aggregate, or both, while maintaining the yield and slump in the required ranges.
5.2Conditions —Concretemixtures shall be prepared both with the air-entraining admixture under test and with the reference admixture. The admixtures shall be added in the amounts necessary to produce the air content selected in accordance with 5.1.3within a tolerance of 60.5%of the volume of concrete.
6. Mixing
6.1Machine mix the concrete as prescribed in Practice C 192/C192M .
7. Tests and Properties of Freshly Mixed Concrete
7.1Test samples of freshly mixed concrete from at least three separate batches for each condition of concrete in accordance with the following methods and the minimum number of tests shall be as prescribed in Table 1. 7.1.1Slump —TestMethod C 143/C143M .
7.1.2Air Content —TestMethod C 231. When lightweight aggregates, air-cooled blast furnace slag, or aggregates of high porosity, for which the aggregate correction factor de?nedin
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Test Method C 231exceeds 0.5%,are used under the provi-sions of 4.4, use Test Method C 173/C173M . 7.1.3Bleeding —TestMethods C 232.
7.1.4Time of Setting —TestMethod C 403/C403M , except that the temperature of each of the ingredients of the concrete mixtures, just prior to mixing, and the temperature at which the time of setting specimens are stored during the test period shall be 23.062°C(7363°F).8. Preparation of Test Specimens
8.1Specimens for test of hardened concrete, representing each test and age of test and each condition of concrete being compared, shall be made from at least three separate batches, and the minimum number of specimens shall be as prescribed in Table 1. On a given day at least one specimen shall be made for each test and age of test from each condition of concrete except that at least two specimens for the freezing and thawing test shall be made from each condition of concrete. The preparation of all specimens shall be completed in three days of mixing.
8.2Manifestly Faulty Specimens —Eachgroup of specimens representing a given test or a given age of test, including tests of freshly mixed concrete, shall be examined visually before or during the test, or both, whichever is appropriate. Discard any specimen found to be manifestly faulty by such examination without testing. Visually examine all specimens representing a given test at a given age after testing, and should any specimen be found to be manifestly faulty, the test results thereof shall be disregarded. Should more than one specimen representing a given test at a given age be found manifestly faulty, either before or after testing, the entire test shall be disregarded and repeated. The test result reported shall be the average of the individual test results of the specimens tested or, in the event that one specimen or one result has been discarded, it shall be the average of the test results of the remaining specimens. 9. Test Specimens of Hardened Concrete
9.1Number of Specimens —Makesix or more test speci-mens for the freezing and thawing test and three or more test specimens for each other type of test and age of test speci?edin Table 1for each condition of concrete to be compared.
TABLE 1Types and Minimum Number of Specimens and Tests
Test
Slump
Air content Bleeding
Time of setting
Compressive strength Flexural strength E
Freezing and thawing Length change E
A B
Number of Types of Specimens A
11111111
Number of Test Ages
111
D
Number of Conditions of Concrete B
22222222
Minimum Number of Specimens
C C
3311
66181812F 6
See Section 7and 9.2. See 4.2. C
Determined on each batch of concrete mixed. D
See 7.1.4. E
Optional tests, see 10.1.5. F
Specimens for duplicate tests from each
batch.
9.2Types of Specimens —Preparespecimens made from concrete with and without the air-entraining admixture under test in accordance with the following:
9.2.1Compressive Strength —Makeand cure test specimens in accordance with Practice C 192/C192M .
9.2.2Flexural Strength —Makeand cure test specimens in accordance with Practice C 192/C192M .
9.2.3Resistance to Freezing and Thawing —Testspecimens shall consist of prisms made and cured in accordance with the applicable requirement of Practice C 192/C192M . Test speci-men dimensions shall be as required by Test Method C 666/C 666M . Make one set of specimens from the concrete mixture containing the air-entraining admixture under test and from the reference concrete mixture, the air content of each mixture being as speci?edin 5.2.
9.2.4Length Change —Makeand cure test specimens in accordance with Test Method C 157/C157M . The moist-curing period, including the period in the molds, shall be 14days.
10. Tests on Hardened Concrete
10.1Test specimens of hardened concrete in accordance with the following test methods:
10.1.1Compressive Strength —TestMethod C 39/C39M . Test specimens at ages of 3, 7, and 28days. Calculate the compressive strength of the concrete containing the admixture under test as a percentage of the compressive strength of the reference concrete as follows:
10.1.1.1Divide the average compressive strength of the specimens made from the concrete containing the admixture under test at a given age of test by the average compressive strength of the specimens made from the reference concrete at the same age of test and multiply the quotient by 100.
10.1.2Flexural Strength —TestMethod C 78. Test speci-mens at ages 3, 7, and 28days. Calculate the ?exuralstrength of the concrete containing the admixture under test as a percentage of the ?exuralstrength of the reference concrete as follows:
10.1.2.1Divide the average ?exuralstrength of the speci-mens made from the concrete containing the admixture under test at a given age of test by the average ?exuralstrength of the specimens made from the reference concrete at the same age of test, and multiply the quotient by 100.
10.1.3Resistance to Freezing and Thawing —ProcedureA of Test Method C 666/C666M . Place specimens under test at the age of 14days.
10.1.4Length Change —TestMethod C 157/C157M . The drying period shall be 14days.
10.1.5The ?exuralstrength and length change tests are applicable only when speci?callyrequired by the purchaser. 11. Check Tests for Uniformity
11.1The check tests enumerated in Speci?cationC 260in the section on Optional Uniformity Requirements shall be determined as follows:
11.1.1pH —ThepH of liquid air-entraining admixtures shall be determined in accordance with Test Method E 70. Non-liquid admixtures shall be prepared in solution to determine pH. Unless there is reason to do otherwise, dissolve the
material in reagent water in the proportions speci?edfor job use as shown on the package or in other manufacturer’sinstructions. The temperature of the check test sample shall be within 61°C(62°F)of that for the acceptance sample and preferably in the range of 21to 27°C(70to 80°F).
11.1.2Air Content of Mortar —Usingthe same amounts of successive lots of air-entraining admixtures with the same cement, determine the air contents of mortars in accordance with Test Method C 185. The air-entraining admixture shall be combined with the mixing water prior to the start of the mixing procedure. The determinations for both the check test sample and acceptance sample shall be made on the same day. 12. Procedure for Residue by Oven Drying
12.1Determine the mass of an aluminum dish (about57mm diameter, 15mm height, and about 1g in weight) to the nearest 0.0001g. Using a pipet, evenly distribute 1ml of the liquid air entraining admixture in the dish, and weigh to the nearest 0.0001g. Place the weighing dish in a drying oven (12.2). Dry for 2562min at 12561°C.At the end of the drying period transfer the weighing dish to a desiccator, cool to room temperature, and weigh to the nearest 0.0001g.
12.2The drying oven shall be either a forced circulation type or one with provision for free access of air. There shall be precise control of temperature and time of drying so that the degree of volatilization of the material other than water from sample to sample will not vary. 12.3Calculation :
12.3.1Record the following weights:
M 1=mass of weighing dish and admixture prior to heat-ing,
M 2=mass of empty weighing dish, M 3=M 1?M 2=mass of sample,
M 4=mass of weighing dish and dried residue, and M 5=M 4?M 2=mass of dried residue.
12.3.2Calculate the residue by using the following equa-tion:
Residue by oven drying ~%by mass ! 5~M 53100! /M 3
(1)
13. Report
13.1Report the following information:
13.1.1Results of the tests speci?edin this method as compared with the requirements of Speci?cationC 260,
13.1.2Brand name, manufacturer’sname and lot number, character of the material, and quantity represented by the sample of the admixture under test,
13.1.3Brand name, manufacturer’sname, and other data on the reference admixture,
13.1.4Brand name, manufacturer’sname, type, and test data on the portland cement or cements used,
13.1.5Description of, and test data on the ?neand coarse aggregates used,
13.1.6Detailed data on the concrete mixtures used, includ-ing amounts and proportions of admixtures used, actual cement factors, water-cement ratios, ratios of ?neto total aggregate, consistency, and air
content.
13.1.7In reporting on check tests for uniformity, report both the initial and current air contents of mortar for the acceptance sample, and the air content of the check test sample, all as determined by Test Method C 185.
14. Precision and Bias 614.1Precision :
14.1.1The single-laboratory coefficient of variation of resi-due by oven drying has been found to be 0.79%.Therefore, the results of two properly conducted tests on the same material in the same laboratory are not expected to differ by more than 2.24%of their average. 7
N OTE 6—Asan example, two tests conducted on the same material yield residues by oven drying of 6.14%and 6.04%,respectively. The
average of these two measurements is 6.09%.The acceptable range of results is then 2.24%of 6.09%or 60.136%.As the difference between 6.14%and 6.04%is 0.10%the results are within the acceptable range.
14.1.2The multilaboratory coefficient of variation of resi-due by oven drying has been found to be 2.35%.Therefore, the results of two properly conducted tests on the same material in different laboratories are not expected to differ by more than 6.65%of their average. 7
14.1.3Other procedures referenced in this test method use results obtained from other ASTM test methods listed in Section 2. These documents are to be referred to for their respective precision statements.
14.2Bias —Sincethere is no accepted reference material suitable for determining the bias of this test method, no statement on bias is made.
15. Keywords
15.1air content; air-entraining admixture; cement; concrete; pH; residue; speci?cgravity
Supporting data have been ?ledat ASTM International Headquarters and may be obtained by requesting Research Report RR:C09-1005. 7
These numbers represent, respectively, the (1s%)and (d2s%)limits as described in Practice C 670
.
6
SUMMARY OF CHANGES
Committee C09has identi?edthe location of selected changes to this test method since the last issue, C 233–04, that may impact the use of this test method. (ApprovedJuly 15, 2007)
(1) Revised 4.2.2, 4.2.3, 4.2.3.1, and 4.2.4.
(2) Added new Note 2and renumbered subsequent notes.
ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
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This standard is copyrighted by ASTM International, 100Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. Individual reprints (singleor multiple copies) of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585(phone),610-832-9555(fax),or service@astm.org(e-mail);or through the ASTM website (www.astm.org).
混凝土引气剂原理
混凝土引气剂原理
混凝土引气基本上都属于阴子表面活性剂，其分子构由憎水基团亲水基团组成，亲水基团在分子溶于水解离后会因释出阳离子而
概括起来讲，引气剂作用机理在于:在混凝土搅拌过程能使其大量裹微小的气泡，而这些微小的气泡又能稳定地在于混凝
具体地分析，引气的作
1) 界面
不加引气剂时，搅拌混凝土程中，也裹入一定量的气泡。但是当加引气剂后，在水泥-水-空气体系中，引气剂子很快吸附在各相界面上。水泥-水界面上，形成憎水基指向泥颗粒，而亲水基指向水的单分子(或多子)定向吸附膜;在气泡(也即水-界面)上，形成憎水基向空，而亲基指向水的定向吸附层。由于表面活性剂的吸附作用，大降了整个体系的自由能，使得在拌过程中，容易引入小气
2) 起泡作用
泡可分为泡、泡沫和溶胶性泡三
清净的水不会起，即使在剧烈或振荡作下，使水中卷入搅成细碎的小气泡混浊，但静置后，气泡立即上浮而破灭。但是当水中加入气剂(比如洗衣粉)后，过振或搅动，便引入大量气泡。其原因是:表面具有自动缩小的趋势，而起泡是一种界面面大量增加的过程，在表面张力变的情况下，然导致体系自由能大大增，是热力不稳定的统，会导致气泡缩小、破灭。但在引气剂存在的情况下，由于它吸气-液界面上，降了界面能，即低了表面张力，因而使起泡较容
3)稳泡作用
通过试验发现，将些表面活性剂加入混凝土中，在搅拌过程中也能引入大量微小泡，但是当将混凝土静置一定时间，或经运输、装卸、浇注后，混凝含气量却大大下降，大部气泡都溢出消了，而引气剂则不同，掺入后，不但能使混凝土在拌程中引入大量微小泡，而且这些气泡
定地存在，是使硬化混凝土存在
研究表明，泡的稳定与静表面力并非简单的关系，还取于一些其它的条件，包括在气周围形成有一定机械度和弹性的膜、要有适当的膜表粘度、适当的液相介质粘度、使泡膜易流失、泡膜动电位提高等，
凝土这样的多项
由于上作用，使得掺加气剂的混凝土在搅过程中所形成的气泡大小均(20-1000μm)，迁移速度小，且相互聚并的可能性也很小，基本上都稳定地存在与
还有一项试验据，也能够帮助说掺加引气剂混凝土中引入气泡的稳定性:一些阴离子引气在含钙量高的水泥浆液中有钙盐沉淀，当微细的水泥粒周围和气泡膜上的这种沉淀物浓度当时，能防止气泡
表1 由香溶液产生的泡在清
松香皂溶液浓度泡沫
(%) 清水 饱和石灰水
0.02 31 380
0.04 54 410
0.08 103 390
引气剂对混凝土性能的影响
高新技术
引气剂对混凝
贺候平
（延安公路局宝
●
’
７１
６０００）
摘要；通过对引气剂工机理的分析。研究引气荆对于混土性能的响，通过试验研究表明，混凝土中添加引气荆，可
爱土的抗冻性，但引气量过高会导致凝土抗冻性能的降。因此，制混凝土中的适宜的引气卉畸掺量将是凝土引气
关键词：混翼土性中
引气荆
舍气量
抗冻性
文献标识码：Ａ
文章编号：１６７２－３７９１（２００８）０５（ｃ）一Ｏ００４～０２
混凝土外加剂技术的展虽然只有５０～６０年历史，比混凝土历史短了１００多，但它的发展速度却非常快，并且在当今的高性能混土技术发展中扮演着重要的角。我国正处于大规模基础建设时期，高，大跨度建筑及桥梁、水工等混凝土工程日益多，这些重大工程的使用寿命接关系到国计生，其耐久性至关重要。混凝土久性的研已经成为土木工程领域的研究热点。在混凝土中掺加引气剂，量均匀、稳定的微小气泡，能够有改善混凝土的孔结构，能大幅
土路用性能。引气混
掺入引气剂后，增加的气泡使得混土的
颗粒可以减小下沉的趋势，同气泡
差异。４．５％含气量的混凝抗冻性指标都能达３００～４００次。引混凝土的折压比普通混凝土提高约２０％，折压比的提高表明了混凝的韧性提高和
混凝土在受压，由于引气剂的掺，引入
１．１．３
泌水的减少可能会
的抹平加工，一般采金属（一般镁制或铝制）工或是适当
于泌水小。经适宜加
力，从而使抗压强度低。混凝土的量一定时，抗压强度的降低还受骨料粒形、最粒径和单位水泥用量等因素的影响。粗骨料的最大粒径大则混凝土抗压强度降低越小。凝土抗弯拉强度主要是由骨料和硬化水浆体之间的界面薄弱程度决定的。在掺用引气剂，由于引气作用减小沉降和泌水象，使混凝土弯拉强度在含气量适当大的情况反而得到善。与普通混凝土相比，引气混凝土的弹性模量降低，含气量对量的影响与对抗压度相近，一般况下不改变强度与弹性模量之间
１．２．３提高了混凝士的久性１．２．３．１善了混凝土抗性混凝土中气体的引入主要是为了改善混凝的抗冻融循环耐久性。冻作用对水泥砂浆和粗细骨料都有一定的影响。混土结构可能受到的冻害可以分为两：单的冻融循环作用和盐冻作用。混凝土受到冻融循环作，由于混凝土气孔中的非结晶水冻结产生了９％的体积膨胀，因产生了膨胀压力，同使得未冻的自由产生迁移，迁移受约束时就会产生渗透压力。混凝土膨胀压力和透压力的作下薄弱环节会产裂缝，经过一定次数循环会最终造成混凝土破坏。当混凝土中掺入引剂入大量均匀分布的微小气，由于气泡的压缩和可以容纳自由水的迁入，因而可以缓解
膨胀压力和渗透压力。目前引气剂作为提
土表面的耐久性。
随着施工技术和高层建筑发展需要，混凝可泵性愈来重。实际上，可泵性是混凝土工作性良的一种特殊表现，由于引气剂增加了混凝土的内聚性和物料间的润滑用，降低了胀流，使泵送时不会度析和泌水，因此加入引气可以可提高混凝上的性。但泵送混凝土的含气量也不宜太高，过大的含气量会成空气可压缩性提高生不饱和状态，加泵压损失，降泵送效率。《混凝土外加剂应技术规范》中规定此类凝土的含气量般要小于６％。混凝土的可泵性还于混凝土的压力泌水量有关，条件下，减少泌水可提混凝士的可泵性。国外和我国大部分城市８０％的泵送
有引气剂成分。
混凝土提高约２０％，提高了混凝土韧性
混凝土裂纹的一个措
时还能明显减少混凝土水。目前．，引气剂作为提混凝士抗冻性的最主要的技术措已经被广泛应用于工程实践中，其效果也得了认可。国内外学者对加入引剂的混凝土性能做了大量研工作，本文作通过对引气剂工作机理的分析，探讨掺入引气剂对土性能的影响，对工实践有很强的指导
１引气剂对
１．１加入引气剂
１．１．１改善
１．２加入引气剂对
１．２．１改变
黄士元教授研究表
由于引气剂的掺入，混凝土中引入大量均匀分，相互独的类球形微小气泡。大量的类球形气泡在混
了滚珠的作用，而大
４％的含气量，可使
１５％以上。原因是
的体积、浆体粘度和应力，因此混凝土拌合的和易性得到了极大的改善和高，坍落度与含气量关系如图ｌ所示。掺引气剂以后，在混凝土配比设计上具有了一定的优：由于引气剂有一定的减水作用，在用水量一定的情况下，掺引气剂可以提高混凝的坍落度，或在
和单位水泥用相同的情况下。掺引气
孔结构体系，封闭了多毛细孔通，同时在水泥颗表面上形僧水膜，从而降低了毛细管的抽吸作用。许多
孔不能被水全部填充，多余的用来缓解物
理膨胀或化学膨胀所成的破坏，由于引气剂有一定的减水作用，所以引气凝土用水量减少，因而拌合物的离析泌水性降低，使得混凝土水分迁移的主要通道（连的大毛细孔）减少，大量封闭的微小气泡的存在也破坏了细管的连续性，从而善混凝土的抗渗
１．２．２影响了
引气作用对混凝土
高混凝土抗冻性的主要技术措施已被广应用于水工和港工等混凝工程实践中，其效果也得到认可。通混凝土引进的最佳含量为３％～６％，砂浆为９％～ｌＯ％。在此范围内，随着含气量的增加，凝土的抗冻性能逐提高，由于引
混凝土中引入很多均
土的密实性。提高
１．１．２降低了
泌水可以看成是混
降，离析可指不同的
彻底改变了其部结构，对混凝土各类
（下转６页）
降速度，进而致混凝土均匀性的坏。
①作者简介：贺平，１９６９年１２，陕
４科技资讯ＳＣＩＥＮＣＥ＆ＴＥＣＨＮＯＬＯＧＹＩＮＦＯＲＭＡＴＩＯＮ
万方数据
盛匿母耥。一
双键羊Ⅱ巯基的收峰，分别为ｉ６３５ｃｍ一１和２５６９ｃｍ一。当超支化树脂过热固化（ｂ）外光固化（ｃ）后，红外图谱中的巯基吸收峰明显消失，且余双键量也有
阳∞∞船∞
高新技术
下一个巯基时，碳自由基取硫醇上的。生成新的硫自由继续引发不和双键聚合。图４所示为巯基被氧化成硫自基并引发
及应用【Ｊ】．中国皮革，２００７，３６（２３）：４７～
５０．
ｆ２】陈立军，陈丽，
高弹性室温自交联丙酸酯聚合物液的制备［Ｊ】．湖南师范
【３】Ｈ．瓦尔森，Ｃ．Ａ．芬奇，等．合成聚合物
乳液的应用（第１
社，２００４．
【４】孟文清，吴利
文，赵正强．室温自交型聚丙烯酸纳米乳液的研究ｆ．ｒｂ．化
【５】谭惠民，罗运．
工业出版社，２００５．【６
ＭａｎｆｒｅｄＬ．Ｈａｌｌｅｎｓｌｅｂｅｎ．Ｅｕｒｏｐｅａｎ
Ｐｏｌｙｍｅｒ
ＲＳｌｌ一．曼！王一ＲＳ．—ＨｚＣ＝—ＣＨＲ＇～
ＲＳＣＨ２＇’ＣＨＲ’—一ＲＳＣＨ２ＣＨ２Ｒ‘＋－Ｓ?
图４
－ＳＨ
巯基被氧化
正因为如此，只树脂表面的巯基会被氧化成硫自由。二是由于没有溶剂的分散用，硫自由基和的运动受到限制，导致自由基无法引发更多的双键聚合，从造成凝胶率较
Ｈ８１
ＨＢ２
ＨＢ３
ＨＢ４
ＨＢ５
∞竹
。
图３超支化树脂
光固化而言，巯含量对凝胶率却没多大影响。因为紫外固化时外加有引发剂，并且由溶剂的分散作用，发剂分子被均匀的分散在树脂中，从而更加有效地引发双键聚合，所得凝胶率也
通过分子设计，们成功的制备了种同时含有巯基和键两种反应性官能团的超支聚合物。并且这合物可以分别在紫外光和加热条件下进行自交联，氧气在热交联的反应过
的作用。
Ｊｏｕｒｎａｌ，１９７６，１３，４３７％４４０．
Ｓ．ｉｎＯｒｇａｎｉｃＣｈｅｍｉｓｔｒｙ
从图３可以明显看出，巯含量越少的树脂，热固化后的胶也越低。而紫外光固化所得凝胶率却较。这种差异的出现，我们觉得是主要两个原因造成的：一是自由基数量差异，热固化过程中没有加引发，单是靠巯基氧化产生的由基来引发双键聚合实现交联ｆ而光引发固化外加的引发剂在紫外光下裂解生自由基引发双键聚合，虽然光引发剂产的自由基（０．１７ｍｍｏｌ／ｇ）和树脂所含巯在同一个量级，但是固化中巯基产的自由基却远没有那么多。这是该树脂热固化的机理…特点决的：基在氧气的作用下生成自由基，且该自由是有引发活性的，引发不饱和双键聚
【７】Ｏｈｎｏ，Ａ．Ｏａｅ
ｏｆ
Ｓｕｌｆｕｒ［Ｍ】．ＯａｅＳ．Ｅｄ．，Ｃｈａｐ．４。
Ｙｏｒｋ。１９７７．
Ｐｌｅｎｕｍ。Ｎｅｗ
参考文献
【１】李仲谨，李小
羟基硅油／聚氯酯
（上接４页）
配置的作用，从而防
他物理膨胀（如盐体结晶压等）和化学胀（如碱骨料反应等）引的混凝土破坏。混凝土耐久性的改程度与引气剂的种类，混凝土的含气量以及气泡的分布特关系很大。掺引气减水剂比掺引气剂对混土的抗冻性更为
在２００
ｕ
参考文献
【ｌ】ＪＴＪ０５３－９４，公路工程水泥混凝土试验
对抗冻性的不影响。经过试确定使混凝土总气量达到４％时，混土的耐久性指数ＤＦ可达到１２０％。然而含气量要控制在最佳范围，否则混凝
会降低。
规程【Ｓ】．北，人民交
凝土耐久性的影响ｆＪ】．低温
【３】邬长森．引剂
用【Ｊ】．建筑技开
【４】陈应钦．引剂
引气剂的研究【Ｊ】．
（２）．
ｍ以下时，尺寸为（Ｏ．３～２）ｕｍ的
．盐冻作用主要由洒化冰盐引起，当化盐溶融时吸收大量溶解热，冰雪下面’或周围的混凝土表面突然降温的作用剥落，且会逐层发展。由于盐冻破坏作用质上也是水结冰膨胀而破坏，因此引气同样对改善混凝抗盐冻性能有
效果。
气孔含量越多，混凝
通过添加引气剂增加混凝中的含气量，可以改善混凝土的易性，混凝抗压强度和劈裂强度不会下降太多，抗弯拉度有一定
通过添加引气剂增加混土中的含气量，可减少混凝土经３００次冻融环后的相对动弹性模量损失，混凝土的抗融性能得
通过添加引气增加混凝土中的气量，可以提高混土的抗渗性能，但是当含量高达６％～８％时，反而会出现抗渗性能的急剧下降，因此，控制适宜的气量是混凝土
【５】傅智．道路混土
公路，１９９８（２）．【６】６宋
响【Ｊ】．中国三峡
【７】姜双伦，姬立
１．２．３．２提高了凝
引气剂的掺入使混凝提高了抗渗性，因而降低侵蚀气体和液体的侵入作用，使得与抗渗性有关的混凝士抗碳化性和化学腐蚀（如抗硫酸盐侵）均有所提高。由手混凝中存在大量封闭的微小气泡可以为膨胀反应物提供容纳空，作为体积膨胀的“冲阀”而降低和
破坏与外加剂【Ｊ】．混
６
万方数据
科技资讯ＳＣＩＥＮＣＥ＆ＴＥＣＨＮＯＬＯＧＹ
ＩＮＦＯＲＭＡＴＩＯＮ
引气剂对混凝土性能的影响
引气剂对混凝
Effect of air entraining agent on concrete performance
学科专业 ： 土木工程
结课时间 ： 2014年12月 年
级 ： 2014级土木工程
研究生学号 ： 研究
绩 ：
引气剂对混凝
摘要 引气剂是常用的混凝土外加之一，许多文献表明掺气剂不仅能够改混凝的工作性，而且还能够提高混凝土的耐久性，增加的使用寿命，特别是在易侵蚀、冻融的环境中。引气混凝土是混土结构耐久性要求发展的然方向。本文系统研究了引气对混凝土的早抗裂性及混凝土耐久性的影响；采用新老凝土结复合立方体试件，通速冻融试验，对在界面剂和新混凝土中掺加引气剂的新老混凝土黏结面的冻劈抗拉性能进行了试验研究；述了引气剂新拌凝和硬化混凝土性能的影，如流动性、离析、泌水和可泵性，以及抗性、抗除冰盐、抗盐结晶压和集料反应破坏等，出引气剂是发展高性混凝土的必备外加剂；探讨了混凝土的渗透性与混凝土耐久性的关和与耐久性之间的关系。研究引气对砂浆和混凝土流性能响，对混凝土耐久性的影响研究具有重要的实用价值
关键词：引气剂；混土；流变性；抗冻融性能； 中图分类
Effect of air entraining agent on concrete performance
Song Jinwei
(College of Civil Engineering and Mechanics , Yanshan University, Qinhuangdao 10216, Hebei）
Abstract ： Air entraining agent is one of concrete admixtures used，many literatures indicate that air entraining agent not only can improve the concrete workability，but also can improve the durability of concrete，increase the service life of concrete，especially in the easy erosion，freeze-thaw environment. Air entraining concrete is the concrete structure durability requirements of the inevitable direction of development.This paper systematically studies the air entraining concrete early cracking resistance and to affect the durability of concrete； using new and old concrete bonding composite cubic specimens，by rapid freeze-thaw test，in the interface agent and new concrete adding lead bonding of new to old concrete surface gas agent freeze-thaw splitting tensile properties were studied； discusses the influence of air entraining agent on the properties of fresh concrete，such as flowability，segregation，secrete water and can pump，and the frost resistance，anti deicing salt resistance，salt crystallization and alkali aggregate reaction damage，and points out that the air entraining agent is essential additives development of high performance concrete is discussed； the relationship between the permeability and durability of concrete and air entraining concrete with durability.Study of air entraining agent on the rheological properties of mortar and concrete influence，has important practical value and theoretical significance to the study of effects of concrete durability.
Keywords： air entraining agent； concrete； rheological properties；freeze-thaw resistance
引 言
20世纪30年代，混土外加剂技术开始被逐渐采，它在很大程度上提高了混凝土耐久性、强度与适用性。如今，外加剂已经为混凝土中必不可少的第五素。近几年，随着高性能混土(HPC)不断发展，混凝土的耐久性也被日益重视，引气剂发和生产逐步变成整外加剂领域的一个
自美国于1937年首创了松香树脂酸引气剂——“文沙”(Vins01)树脂，并于1938年获得专利，各也相继发表了有关的研究成果，并制定了相关的引气剂标准规范。“沙”树脂最初主被应用于提
地区路面混凝土和坝混凝土冻性。上世纪40年代，引气剂得了快速的发展，种类越来越多、性能越发完，并在现代混凝土中占据不可替代的作用。如：北美、北、日本等发达地区和国家都十分重视混土工程的耐久性，早已普推广了各种气剂技术，据不完统计，这些地区国家约有80％以上的混凝土工程都采用引气剂，其水工、港工和桥梁等重要工中更是明文规定必须要掺
20世纪50年代，我国开研发引气剂，70年代以后，引气的科研、生产应用取得了许多重大进展，但产品的性能和质量国外同类
在一定差距。同时，国内不少对引气的使用仍有顾虑，因害怕含气会影响混凝土强度，一度限制引气剂的使用围，能不掺的就尽量不掺，这就不利于耐久性的改善，影响工结构的安全使用寿命。另外，大量的施单位反映松香类引气剂稳性欠佳，影工程质量而不愿意使；同时，研制生产单位也受到市场经济效益影响(研发成本高、市场)，而不愿意研制和生产；这些极大地制约了引气剂的推
1 引气剂的
1.1引气剂的分类
从化学结构来看，引气其实是一种表性剂，具起泡、乳化分散、浸润等性能。如果从面活性剂理论来分类，引气剂可以分为阴离子、阳离子、非子和两性离子等类型。但是，实的丁.程应用中，大多引气剂均属于阴离面活性剂，而且过去应用在混凝土中的表面活性剂种类有限，因此，引气剂的种类在凝土领域中，般都是根据生产引气剂的原来划分的[15]。要可分为以下几种： (1)松香类引气剂：通过不同各种工艺对松香性得到的松香衍生物，根据不同的改性法可分为松香阜类和松香热聚物类
(2)院基苯 酸盐类引剂：一般是焼苯用浓硫酸、发烟酸或液体三化硫作为 化剂而制得的产品，主要有烧基磺酸钠和
(3)阜苷类引气剂：初是从多年生木阜荚树果实阜角阜荚中提取来的一种辛辣刺鼻的物质，其主要成分为略试，引
(4)脂肪醇酸盐类引气剂：要有脂肪醇聚氧乙醚、脂肪醇聚氧乙稀碌酸和脂肪醇硫酸钠。其中脂肪醇聚氧乙稀醚简称醇醚，是非离子型表面活性中发展较快，
(5)其它：要有蛋白质盐、石油 酸盐和一具有较强引气功能的减剂等。其中引减水剂主要有改性木质素礎酸盐和聚焼基芳基磺酸盐。 1.2引
引气剂的首要功能是引入泡，其次还有分和润湿的作用。不引气剂的分结构不同，其起泡性和稳泡性存在差异，影响泡性能的主
表面张力、表面电荷、表面度以及气体的透。大部分引剂为阴离子表面活性剂，存在憎水基团和亲基团，在混凝土水泥一水一气组成的界面上，憎水基向空气一面定向吸，亲水基与水泥颗粒和水化粒子相附，在水泥颗粒及其水化粒子表上形成憎水化吸附层，种吸附层在憎水基的作用下力图靠近空气表面，引气剂在这种重界面上的吸附作用著降低了水的表张力，使在搅拌过中混凝土能引入大量的气泡，且些气泡带有同的电荷，互排斥，因此些气泡能均勻分布在混凝土中如果盐的含量较高，引气剂会使韩盐生并吸附在气泡的液膜表，增加了气泡的厚，有效防止了气泡的破灭，提高了气泡
稳泡性的另一个影因素是气泡形成泡的机械强度，引气剂分子链的长及其分子量的大小与泡膜的机械强度密切相关，子链愈长，分子量愈大，分间的范德华力愈大，相应其气泡膜机械强度也就愈大。除此之外，泡膜粘度对泡稳定性也有一定影响，泡粘度表示其动性，粘度小的泡膜流性较，搅拌时易产生气泡，但这样的气泡的泡膜一般比较薄易破裂，因剂要达到较佳的引气效果，要其拥有较好的起泡性能和稳
2 引气剂对混
2.1 掺引气剂对
引气剂及高效减水剂的，混凝土中游离水明显减少，匀细小气泡不但有一定的保温作用，更重要的是可以缓受冻水结冰后产生的膨胀力，减少混凝土冻害。资料表，掺入引气剂的混凝土抗冻性可提高8～15，从表2-1可以看出掺引气剂混凝土的抗冻性能不但高于空白混凝土也高单掺高效减水剂的混
表1-1 掺用引气
Table1-1 Durability of concrete mixed with air entraining agent
2.2 掺引气剂
提高混凝土抗侵蚀能力关在于提高混凝土实性及抗渗性能，也是掺引气及高效减水剂混凝土有较好抗侵蚀性能的机理(见图2-1
。
图2-1 含气量对
Fig.2-1 Influence of air content on durability of concrete
2.3 掺引气剂对
水灰比是影响渗透性能的要因素。水灰比包围水泥粒防水层越厚，许多拌合水在水泥石中形相互通连而无规则的毛细孔通道，增加了混凝土的透水性，掺加引剂及高效减水剂的混凝土水灰都在0.5以下，甚至可达0.3以下，混凝土中孔隙改变，加之引气剂产生的细小均匀独立而不相通的气泡，效地隔断了混凝土的毛细孔通道，止水分渗透。我们用多种方法测试表明，掺用引剂的混凝抗渗标号达S12以上，即在2 MPa以上水压下也不会透水。工程实践说明，以引剂水剂配制的混凝土无再采用其它防水措，即可达到防水抗渗目的，经济效益
2.4 掺引气剂混
引气剂的掺入使混提高了抗渗性，因而降了侵蚀气体和液体的侵入用，使得与抗渗性有关的混凝土抗碳性和抗化学腐蚀 ( 如硫酸盐侵蚀) 均有所提高。由于混土中存在大量的封闭的微小气泡可以为膨反应物提供容纳空间，作为体积膨胀
冲阀”而降低和延其他物理 ( 盐晶体结晶压等) 和化学胀 ( 如碱骨料反应等) 引起的混凝土坏。混凝土耐久性的改善度与混凝土的含气量，引气剂的类以及气泡的分布有很大关系，各国引混凝土适宜含气量推荐值表2-2。验资料表明，掺引剂及减水剂的混土孔隙率小，混凝土密实，加之细小气泡。可使混土化速度降低，提高了混凝土碳化性能，减少了钢筋锈
表2-2 各国引
Table 2-2 countries air entraining concrete suitable for gas
content
2.5 改善了
引气剂能在混凝土中
立的类球形微小气泡，们在混凝土中了滚珠的作，增加了浆体体积、浆体粘度，使混凝拌和物的和易性得到了极大的提高，坍落度与含气量关系如2-2所示。引气剂具有一定减作用，在用水量一定的况下，掺入引气剂可提高混凝土的坍落度； 或在坍落度和单位水泥用量同的情况下，掺入引气剂可以减少位用水量，从而加了混凝土的密实性，提高混凝土的久性。在入引气剂后，增加的气泡使得混凝土的内聚力和均匀性都增加，气泡黏着颗粒可以减小其下的趋势，同时也小水的流动进而降低了混凝土的泌
图2-2 坍落
Fig.2-1 The relationship between slump and air content
2.6含气量与强度
图3显示了混凝土7d和抗折强度随含气量的变化规。由图2-3a可看到，混凝土抗强度随含气量增加渐下降，同含气量下，第1组混凝土的抗压强度比第2组；而从图2-3b可看到，当气量小于6%时，随着含气量的增加，混凝土抗折强度不仅没有明显的下势，反而略有提高。气量对混凝土强度的
图2-3a 含气量
Fig. 2-3a containing gas and compressive strength of concrete
7d
图2-3b 含气量
Fig.2-3b content and flexural strength of concrete 7d
3 冻融时引气剂对新老凝
通过对试验结果的分析，得以下结论：(1)界面剂中掺引剂可以显著改善新、老混凝土黏结面的抗性能。对所试验的试件，在其它条件相同时，掺加引气剂后，黏结面的冻能力可提高一倍以上；(2)界剂中入引气剂后产生的大量均、稳定、互不连通的微泡，使新、老混凝土黏结面的饱水度降低，冰冻过程中，这小气泡将缓解水结冰生的体积膨胀压，避免生成破坏应，提高了黏结面的抗冻性能；(3)新、老凝土黏结面的裂抗拉强度随融循环次数的增加呈下降趋势。在界面剂和新混凝土中加入引气剂新、凝土黏结面与未掺加引剂的相比，黏面裂抗拉强度随冻融循环次数增加呈下降的
图3-1 未掺引气剂黏结面劈强度随冻融次数的变
tensile strength varies with the number of freezing and thawing
图3-2 掺加气剂黏结面劈拉
number of freezing and thawing agent binding surface
4 引气剂对混凝土
4.1 引气剂对
对于同种引气剂，引剂溶液的表力随溶液度的增大而降低，降低趋势逐渐缓；溶液的起泡性能和消泡时间随溶液浓度的增大而加，随溶液表面张力的降低而加。低流态时，引气剂均大幅提高了砂的流动度，且流动度随引气剂的掺量增加而增。高流态时，引气剂略微降低砂浆的流动，且流动度随着引气剂掺的增加稍有降，最后趋于稳定。以上几种现象均可能是引气剂引入气泡的滚轴用和塑性粘度提高双向作用的结
(n=l)流体模
砂浆的屈服
高性能混凝土的用水量较，流动好，抗离析能力高，填充能优异。高性能混凝土针对不同用途要，以混凝土结构耐久为主要目标。引气剂能改善凝土拌合物的工作性，大幅提高混土结构的耐久性。因，引气剂高性能混凝土必可少的外加剂之一。由图4-1可知，随着引气剂掺量的提，性能混凝土屈服应力和性粘度也相应增大。混
落度随引气剂掺的提高稍有降低，也是
图4-1 引剂对高性能混凝
coagulating ten rheological properties
5 结论
通过大量工程实践检测资料表明，以适当气剂所配制的高强HPC要技术性能完全高于以高效减水剂其它外加剂配制的高凝土，主要表现在： (1)混凝流动性更好，保水性改善，保塑性更好，能进一步降低混凝坍落度经时损
(2)混凝土抗、抗渗、化等久性能不但高于空白混凝土，也远远高于单掺高效减水剂的混凝土。 (3)随着新拌混凝土气量的增大，混凝土抗压强度低，在一定含气量范围内，抗折强度有提高，混凝土折压比大。在相抗压强度的情况下，引气混凝土的抗折强度明显高于非引气混凝土。对于以弯拉强度要指标的混凝土，引气剂能幅提高混凝土强度的
(4)同强度下，引气剂以显
同水胶比下，含气量增大，引气混土和
(4)在界面中掺加引气可以显著改善新、老混凝土黏结面的抗冻能。对所试验试件，在其它条件相同时，掺加引气剂后，黏结面抗冻能力可
(5)界面剂中加引气剂后产生的大均匀、稳定、互不连通微小气泡，使新、老混凝土黏面的饱水度降低，冰过程中，这些微小气泡将缓解结冰产生的体积膨胀压力，避免生成坏应力，提高了结面的抗冻
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