• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.13-18
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• 2003

The concrete structure can be easily damaged due to alkali-aggregate reaction. The alkali-aggregate reaction is a reaction between the alkalies(K or Na) in cement and an unstable mineral of the aggregates. There are several test methods to identify alkali reactivity of aggregates. In general, crushed stones are tested by petrographic examination, chemical method and 모르타르 바 method. This study tested alkali-aggregate reactivity of crushed stones that has different rock types such as granitic, volcanic, metamorphic and sedimentary rocks. Samples are collected from 12 local aggregate production companies. Alkali-reactivity of various rock types was evaluated by using ASTM C 227 and C 1260, and compared the test results of two test methods.

• Proceedings of the Korea Concrete Institute Conference
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• 1989.10a
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• pp.1-4
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• 1989

Recently, as the natural aggregates are exhausted, using the crashed stones bring the possibility of the alkali-aggregate reactivity. In this study, the samples are collected from the stony moutains chosen by using a geoligical survey map and analyzed in terms of the amount and the shape of the reaction minerals by a polarization microscope and X-ray diffraction which beling to the petrographic examination of aggregates for concrete. From this study, most samples of the sedimentary rocks and the granitte of the ignious rocks show the possibility of the alkali-aggregate reactivity.

• Computers and Concrete
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• v.8 no.6
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• pp.617-629
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• 2011

In this investigation, reservoir sediment and municipal sewage sludge were sintered to form the artificial lightweight aggregates. The sintered aggregates were compared with the commercialized lightweight aggregates to in terms of potential alkali-silica reactivity and chemical stability based on analyses of their physical and chemical properties, leaching of heavy metal, alkali-silica reactivity, crystal phase species and microstructure. Experimental results demonstrated that the degree of sintering of an aggregate affected the chemical resistance more strongly than did its chemical composition. According to ASTM C289-94, all potential alkali-silica reactivity of artificial lightweight aggregates were in the harmless zone, while the potential reactivity of artificial lightweight aggregates made from reservoir sediment and municipal sewage sludge were much lower than those of traditional lightweight aggregates.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.10a
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• pp.50-53
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• 1992

The damages due to alkali-aggregate reaction between the reactive silicia constituents of the aggregate and the alkalies in cement have been frequently reported since 1923 in America . Recently alkali-aggregate reaction, especially alkali-silica reaction, can be found all over the area using crushed stones. The first research, in 1990, was performed to identify the alkali-silica reactivity of 18 sets of crushed stones used in domestic ready-mixed concrete plant as coarse aggregates by 4 petrollgical, chemical and mortar bar method, And the study was continued with 10 sets of crushed stones in this research. It was found that all the aggregates used in this study are innocuous at alkali-silica reaction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.172-173
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• 2022

Rough stones of aggregates used as concrete aggregates for 6 regions in Korea were sampled and the reactivity of alkali aggregates was analyzed using chemical analysis method and mortar rod method.

• Computers and Concrete
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• v.20 no.6
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• pp.705-710
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• 2017

The effectiveness of mineral additives in suppressing alkali-silica reactivity has been studied in this work. Experimentation has been performed in accordance with the procedures prescribed in ASTM C 1567. In the scope of the investigation, a quarry aggregate which was reactive according to ASTM C 1260 was tested. In the experimental program, prismatic mortar specimens measuring $25{\times}25{\times}285mm$ were produced. Ten sets of production, three specimens for each set, were made. Length changes were measured at the end of 3, 7, 14 and 28 days and then expansions in percentage have been calculated. Fly ash, silica fume, and metakaolin have been used as cement replacement in different ratios for the testing of the alkali-silicate reactivity of the aggregate. In the mixes performed, the replacement ratios were 20%, 40%, and 60% for the fly ash, and 5%, 10%, and 15% for the silica fume, and 5%, 10%, and 15% for the metakaolin. Mixes without mineral additives were also produced for comparison. The beneficial effect in suppressing alkali-silica reactivity is highly noticeable as the replacement ratios of the mineral additives increase regardless of the type of the mineral additive used. Being more concise, the optimum concentrations of using silica fume and metakaolin in mortar in suppressing ASR is 10%, respectively, while it is 20% for fly ash.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.93-98
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• 1991

The damages due to alkali-aggragate reaction between the reactive silica constituents of the aggregate and the alkalies in cement have been frequently reported since 1923 in America. Recently, alkali-aggregate reaction, especially alkali-silica reaction, can be found all over the area using crushed stones. This research was performed to indentify the alkali-silica reactivity of 18 sets of crushed stones being used currently in domestic reacy-mixed concrete plant as coarse aggregates by petrollogical, chemical and mortar bar method. It is found that all the aggregates used in this study are innocuous at alkali-silica reaction. Further study will be carried out with some aggregates in more severe conditions.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.93-99
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• 2012

PURPOSES: The purpose of this study is to compare the alkali-silica reactivity for mortar bar and concrete prism specimens using crushed aggregates of 5 types in Korea. And the alkali-silica reactivity for those aggregates are measured by chemical test method. METHODS: The alkali-silica reactivity for those aggregates was measured by chemical test method of KS F 2545, mortar-bar test of KS F 2546, accelerated mortar-bar test method of ASTM C 1260 and concrete prism test method of ASTM C 1293, relatively. RESULTS: The alkali-silica reactivity for those aggregates was verified by chemical test of KS F 2546 and accelerated mortar-bar test of ASTM C 1260. However, it was not by mortar-bar test of KS F 2546 and concrete prism test of ASTM C 1293. CONCLUSIONS: The above results showed that relationship among the four test methods were very low. The results from 3 types of test methods using cement-aggregate combinations appeared to be different. Because the environmental conditions of test methods for measuring the alkali-silica reactivity such as equivalent alkali content(external source), humidity, temperature, and times were different though the aggregates were same. Moreover, alkali-silica reactivity showed the biggest impact when alkalis were supplied form outside and exposed to environmental conditions. The accelerated mortar-bar test method seems to be most appropriate test method for concrete structures exposed to alkali environment.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.195-196
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• 2020

This study evaluated the mechanical properties and alkali silica reaction of mortar according to the mixing ratio of waste glass. As a result, as the mixing ratio of the waste glass increased, the compressive and flexible strength of the mortar decreased due to the slip of aggregate, and the alkali-silica reaction(ASR) increased. So, it is considered that research is needed to prevent slip and ASR of the waste glass aggregate in order to use the waste glass as a fine aggregate for concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.31-32
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• 2020

This study measured the mechanical performance and residual strength of high strength/normal strength mortar mixed with waste glass fine aggregate after alkali-silica reaction and alkali-silica reaction. As a result, the effect of improving the slip phenomenon of the waste glass fine aggregate in the high-strength mortar was not significant, but rather the amount of ASR was increased.