【国外标准】 Standard Test Method for Determining the Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials and Aggregate (Accelerated Mortar-Bar Method)

4.1 This test method provides a means for evaluating the ability of pozzolans and slag cement to control deleterious internal expansion due to alkali-silica reaction when used with an aggregate intended for use in concrete. It is based on the Accelerated Test Method developed at the National Building Research Institute (NBRI) in the Republic of South Africa (1-4).34.2 This test method has been developed for evaluating combinations of certain cementitious materials with a single aggregate source in a mortar of standard proportions. It yields an empirical result, which is utilized to compare to criteria within some specifications to accept or reject the combination of materials being evaluated for a particular application. Currently this method has no standard procedure for testing fine and coarse aggregates proposed for use in concrete together in a single batch of mortar, nor for varying the proportions of the constituent materials of the mortar beyond the relative proportions of the individual cementitious material constituents to each other, as the significance of these practices have not been determined nor have appropriate limits been established for evaluating the results of tests conducted using these modifications.4.3 Different levels of pozzolan and slag cement may require testing to determine the amount required to reduce expansion to an acceptable level. Pozzolans and ground granulated blast-furnace slag may be tested separately or in combination.4.4 It is recommended to test the same aggregate and hydraulic cement (without pozzolans and slag cement) using Test Method C1260.4.5 Results of tests conducted as described herein shall form a part of the basis for determining the precautions that shall be taken against excessive expansion due to alkali-silica reaction. Refer to Guide C1778 for the interpretation of the test results from Test Method C1567.1.1 This test method permits detection within 16 days of the potential for deleterious alkali-silica reaction of combinations of cementitious materials and aggregate in mortar bars. The cementitious materials are composed of various proportions of hydraulic cement, pozzolans and slag cement.1.2 The test results are only valid for the specific combinations of pozzolan, slag, and reactive aggregates tested.1.3 This test is not suitable for evaluating the potential for deleterious reaction of combinations of hydraulic cement and aggregate (that is, in the absence of pozzolans or slag cement).1.4 The text of this test method refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this test method.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.