Significance and Use
This test method provides a means for evaluating the ability of pozzolans and ground granulated blast-furnace slag 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).
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.
Results obtained using this test method may overestimate the reactivity of some types of aggregates if used in service with the same pozzolans or slag and hydraulic cement of low alkali content.
Different levels of pozzolan and ground granulated blast-furnace slag 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.
It is recommended to test the same aggregate and hydraulic cement (without pozzolans and slag) using Test Method C1260.
This test method may underestimate the expansion of cementitious systems containing pozzolans with an alkali content > 4.0 % sodium oxide equivalent (7-9). It is recommended that such materials be tested using Test Method C1293.
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 ground granulated blast-furnace slag.
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 ground granulated blast-furnace slag).
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 determine the applicability of regulatory limitations prior to use. A specific precautionary statement is given in the section on Reagents.