Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method). ASTM C Standard Test Method for Potential Alkali Reactivity of Cement- Aggregate Combinations (Mortar-Bar Method). All the Controls products ASTM C standard. Enter now!.
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Insignificant expansion may result when potentially deleteriously reactive siliceous rocks are present in comparatively high proportion even when a high-alkali cement is used.
Data correlating the results of tests performed using this test method with performance of cement-aggregate combinations in concrete in service, results of petrographic examination of aggregates Guide Aetmand results of tests for potential reactivity of aggregates by chemical methods have been published in Test Method C and should be consulted in connection with the use of results of tests performed using this test method as the basis for conclusions and recommendations concerning the use of cement-aggregate combinations in concrete.
Formerly under the jurisdiction of Committee C09 on Concrete and Concrete Aggregates, this test method was withdrawn in October It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of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.
ASTM C, Test equipment Controls
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.
Two types of alkali reactivity of aggregates are recognized: The method is not recommended as a means to detect the latter reaction because expansions produced in the mortar-bar test by the alkali-carbonate reaction see Test Method C are generally much less than those produced by the alkali-silica reaction for combinations having equally harmful effects in service.
This may occur because the alkali-silica reaction products are characterized by an alkali to silica ratio that is so low as to minimize uptake of water and swelling, or because of alkali leaching from the bars see section on containers. Also, significant expansion may occur rarely in the test for reasons other than alkali-aggregate reaction, particularly the presence of sulfates in the aggregate that produce a sulfate attack upon the cement paste, ferrous sulfides pyrite, marcasite, or pyrrhotite that oxidize and hydrate with the release of sulfate, and materials such as free lime CaO or free magnesia MgO in the cement or aggregate that progressively hydrate and carbonate.
When expansions in excess of those given in the Appendix of Specification C33 are shown in results of tests performed using this test method, it is strongly recommended that supplementary information be developed to confirm that the expansion is actually due to alkali reactivity. Dolomitic aggregates that are deleteriously affected by the alkali-carbonate reaction when employed as course aggregate in concrete may not produce notable expansion in this test method.
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This test method covered the determination of the susceptibility of cement-aggregate combinations to expansive reactions involving hydroxyl ions associated with the alkalies sodium and potassium by measurement of the increase or decrease in length of mortar bars containing the combination during storage under prescribed conditions. The method is not recommended as a means to detect the latter reaction because expansions produced in the mortar-bar test by the alkali-carbonate reaction see Test Method C are generally much less than those produced by the alkali-silica reaction for combinations having equally harmful effects in service.
When it has been concluded from the results of tests performed using this test method and supplementary information as outlined that a given cement-aggregate combination should be considered potentially deleteriously reactive, additional studies may be appropriate to develop information on the potential reactivity of other combinations containing the same cement with other aggregates, the same aggregate with other cements, or the same cement-aggregate combination with a mineral admixture.
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Criteria to determine potential deleterious alkali-silica reactivity of cement-aggregate combinations from the results of this test method have been given in the Appendix of Specification C Two types of alkali reactivity of aggregates are recognized: This test method is being withdrawn without replacement due to its limited use by industry.
The results of tests performed using this method furnish information on the likelihood that a cement-aggregate combination is potentially capable of harmful alkali-silica reactivity with consequent deleterious expansion of concrete.
Sources of such supplementary information include: