AASHTO T 276-2015 Standard Method of Test for Measuring Early-Age Compression Strength and Projecting Later-Age Strength.pdf
《AASHTO T 276-2015 Standard Method of Test for Measuring Early-Age Compression Strength and Projecting Later-Age Strength.pdf》由会员分享,可在线阅读,更多相关《AASHTO T 276-2015 Standard Method of Test for Measuring Early-Age Compression Strength and Projecting Later-Age Strength.pdf(11页珍藏版)》请在麦多课文档分享上搜索。
1、Standard Method of Test for Measuring Early-Age Compression Strength and Projecting Later-Age Strength AASHTO Designation: T 276-15 ASTM Designation: C918-07 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3c T 276
2、-1 AASHTO Standard Method of Test for Measuring Early-Age Compression Strength and Projecting Later-Age Strength AASHTO Designation: T 276-15 ASTM Designation: C918-07 1. SCOPE 1.1. This test method covers a procedure for making and curing concrete specimens and for testing them at an early age. The
3、 specimens are stored under standard curing conditions and the measured temperature history is used to compute a maturity index that is related to strength gain. 1.2. This test method also covers a procedure for using the results of early-age compressive-strength tests to project the potential stren
4、gth of concrete at later ages. 1.3. The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4. The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those
5、in tables and figures) shall not be considered as requirements of the standard. 1.5. This 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 appropriate safety and health practices and d
6、etermine the applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 205M/M 205, Molds for Forming Concrete Test Cylinders Vertically R 39, Making and Curing Concrete Test Specimens in the Laboratory R 60, Sampling Freshly Mixed Concrete T 22, Compressi
7、ve Strength of Cylindrical Concrete Specimens T 23, Making and Curing Concrete Test Specimens in the Field T 231, Capping Cylindrical Concrete Specimens 2.2. ASTM Standards: C617/C617M, Standard Practice for Capping Cylindrical Concrete Specimens C670, Standard Practice for Preparing Precision and B
8、ias Statements for Test Methods for Construction Materials C1074, Standard Practice for Estimating Concrete Strength by the Maturity Method C1231/C1231M, Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Concrete Cylinders 2015 by the American Associatio
9、n of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 276-2 AASHTO 3. TERMINOLOGY 3.1. Definitions: 3.1.1. Refer to ASTM C1074 for the definition of the following terms: datum temperature, equivalent age, maturity, maturity function
10、, maturity index, and temperaturetime factor. 3.2. Definition of Terms Specific to This Standard: 3.2.1. potential strengththe strength of a test specimen that would be obtained at a specified age under standard curing conditions. 3.2.2. prediction equationthe equation representing the straight-line
11、 relationship between compressive strength and the logarithm of the maturity index. 3.2.2.1. DiscussionThe prediction equation is used to project the strength of a test specimen based upon its measured early-age strength. The general form of the prediction equation used in this test method is: ( )lo
12、g logMmS Sb M m=+ (1) where: SM= predicted strength at maturity index, M; Sm= measured compressive strength at maturity index, m; b = slope of the line; M = maturity index under standard curing conditions; and m = maturity index of the specimen tested at early age. The prediction equation is develop
13、ed by performing compressive strength tests at various ages, computing the corresponding maturity indices at the test ages, and plotting the compressive strength as a function of the logarithm of the maturity index. A best-fit line is drawn through the data and the slope of this line is used in the
14、prediction equation. 3.2.3. projected strengththe potential strength estimated by using the measured early-age strength and the previously established prediction equation. 4. SUMMARY OF TEST METHOD 4.1. Cylindrical test specimens are prepared and cured in accordance with the appropriate section of T
15、 23 or in accordance with R 39. The temperature of a representative specimen is monitored during the curing period. Specimens are tested for compressive strength at an early age beyond 24 h, and the concrete temperature history is used to compute the maturity index at the time of test. 4.2. A proced
16、ure is presented for acquiring a series of compressive strength values and the corresponding maturity indices at different ages. These data are used to develop a prediction equation that is used subsequently to project the strengths at later ages based upon measured early-age strengths. 2015 by the
17、American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3c T 276-3 AASHTO 5. SIGNIFICANCE AND USE 5.1. This test method provides a procedure to estimate the potential strength of a particular test specimen based upon its
18、 measured strength at an age as early as 24 h. The early-age test results provide information on the variability of the concrete production process for use in process control. 5.2. The relationship between early-age strength of a test specimen and strength achieved at some later age under standard c
19、uring depends upon the materials comprising the concrete. In this test method, it is assumed that there is a linear relationship between strength and the logarithm of the maturity index. Experience has shown that this is an acceptable approximation for test ages between 24 h and 28 days under standa
20、rd curing conditions. The user of this method shall verify that the test data used to develop the prediction equation are represented correctly by the linear relationship. If the underlying relationship between strength and the logarithm of the maturity index cannot be approximated by a straight lin
21、e, the principle of this test method is applicable provided an approximate equation is used to represent the nonlinear relationship. 5.3. Strength projections are limited to concretes using the same materials and proportions as the concrete used to establish the prediction equation. Note 1Confidence
22、 intervals developed in accordance with the appendix are helpful in evaluating predictions. 5.4. This test method is not intended for estimating the in-place strength of concrete. ASTM C1074 provides procedures for using the measured in-place maturity index to estimate in-place strength. 6. APPARATU
23、S 6.1. Equipment and Small Toolsfor fabricating specimens and measuring the characteristics of fresh concrete; shall conform to the applicable requirements of R 39 or T 23. 6.2. Moldsshall conform to the requirements for cylinder molds in Specification M 205M/M 205. 6.3. Temperature Recorder: 6.3.1.
24、 A device is required to monitor and record the temperature of a test specimen as a function of time. Acceptable devices include thermocouples or thermistors connected to a continuous chart recorder or digital data-loggers. For digital instruments, the recording time interval shall be 1/2h or less f
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
5000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- AASHTOT2762015STANDARDMETHODOFTESTFORMEASURINGEARLYAGECOMPRESSIONSTRENGTHANDPROJECTINGLATERAGESTRENGTHPDF

链接地址:http://www.mydoc123.com/p-418215.html