• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.111-117
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• 1995

The alkali-aggregate reaction is a reaction between the alkali metals in the pore water of a concrete and an unstable mineral of the aggregate. There are three types of alkali-aggregate reation which causes deterioration of concrete, such as alkali-silicate reation, alkali-carbonate reaction and alkali-silica reation. Deterioration due to alkali-silica reation is more comon than that due to either the alkali-silicate or alkali-carbonate reaction. The alkali-silica reation is a reaction between the hydroxyl ions in the pore water of a concrete and silica which exists in signigicant quantities in the aggregate. In this PAPER, Alkali-aggregate reactions of mortar made with various abroad aggregate were investigated using XRD, microscope, chemical and physical tests. In additions, the effects of the texture of aggregate, Na, K, CI ion concentrations added to the mortar, on these reactions were studied.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.137-140
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• 1996

The deterioration of concrete due to alkali-aggregate reaction is dependent on the total alkali content per unit volume of concrete. It was reported that the expansion of high alkali concrete with the reactive aggregate increased easily due to high alkali of concrete with the reactive aggregate increased easily. And it has been confirmed that the addition of pozzolanic material prevents the concrete with reactive aggregate from deterioration caused by alkali-aggregate reaction. It is the aim of this study to provide the fundamental data on the possibility of alkali-aggregate reaction of high strength concrete and its preventing and repair technic.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.249-254
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• 2002

In Korea, due to the shortcomings of natural aggregates and increasing needs of crushed stones, it is necessary to examine the alkali-aggregate reaction of the crushed stones. The purpose of this study is to analyze petrographic properties and alkali-aggregate reaction of crushed stones This study was peformed to investigate the alkali-aggregate reaction of crushed stones using chemical analysis, physical properties, XRD, XRF and mortar-bar method.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.549-554
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• 2001

The authors have proposed that waste glass, which is crushed to pieces, can be used as a concrete aggregate. At the present time, recycled-glass concrete is used for sidewalk concrete blocks and pavement as glass is ornamental. However, in cases where recycled-glass concrete is used for structural concrete, strength and durability are required as structural concrete is exposed to the weather. Glass that is used generally is a mixture of SiO$_2$, Na$_2$O and CaO. SiO$_2$is the most likely cause of alkali-aggregate reaction when waste glass was used for concrete aggregate. In this study, an alkali-aggregate reaction test that is one of the important tests related to durability of aggregate was carried out far discussion of utilization of waste glass for concrete aggregate. From the results of the tests, it is found that glass is a reactive aggregate. The pessimum proportion of glass is about 75%. Then the cases of using fly ash, blast furnace slag and artificial zeolite for admixture materials were also examined for the purpose of prevention of alkali-aggregate reaction. from the results of the test, it was found that using them is an effective way to prevent alkali-aggregate reaction. The compressive strength in the cases of using admixture materials is larger than that without admixture materials.

• 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.

• Computers and Concrete
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• v.16 no.1
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• pp.37-48
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• 2015

Alkali aggregate reaction affects numerous civil engineering structures and causes irreversible expansion and cracking. This work aims at developing model to predict the potential expansion of concrete containing alkali-reactive aggregates. First, the paper presents the experimental results concerning the influence of particle size of an alkali-reactive aggregate on mortar expansion studied at 0.15-0.80 mm, 1.25-2.50 mm and 2.5-5.0 mm size fractions and gives data necessary for model development. Results show that no expansion was measured on the mortars using small particles (0.15-0.80 mm) while the particles (1.25-2.50 mm) gave the largest expansions. Finally, model is proposed to simulate the experimental results by studying correlations between the measured expansions and the size of aggregates and to calculate the thickness of the porous zone necessary to take again all the volume of the gel created by this chemical reaction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.23-24
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• 2020

In this study, effect of surface modification of waste glass for fine aggregates on the mechanical properties and alkali silica reaction of mortar was analyzed. As a result, it was confirmed that the incorporation of waste glass fine aggregate decreases the mechanical properties of the mortar and increase the alkali silica reaction expansion. On the other hand, the surface modification of the waste glass fine aggregate is effective in improving this problem. However, unlike green and brown waste glass, it is judged that an additional experiment to determine the cause is necessary for white waste glass where alkali silica reactive expansion occurs extremely.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.19-24
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• 2015

PURPOSES : The objective of this study is to evaluate the effect of the residual mortar of recycled concrete aggregate on the expansion behavior during alkali silica reaction (ASR). METHODS: In order to evaluate the net effect of residual mortar on ASR expansion behavior, two aggregate samples with the same original virgin aggregate source but different residual mortar volumes were used. ASTM C1260 test was used to evaluate the ASR expansion behavior of these two aggregates and the original virgin aggregate. RESULTS: The greater the amount of residual mortar in recycled concrete aggregates, the less is the induced ASR expansion. Depending on the amount of residual mortar in recycled concrete aggregate, the ASR expansion of recycled concrete aggregate may be less than half of that of the original virgin aggregate. CONCLUSIONS: The residual mortar of recycled concrete aggregate may lead to the under estimation of the ASR expansion behavior of the original virgin aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.435-438
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• 2005

The effect of content of reactive aggregate on alkali-silica reaction was investigated through the ASTM C 1260 method. The replacement proportions of fine aggregate by reactive aggregate were 25, 50, 75 and $100\%$, respectively. Reactive aggregate and fine aggregate(non-reactive aggregate) used are a metamorphic rock and andesite rock, respectively. The results indicate that the mortar-bar containing $25\%$ replacement of fine aggregate by reactive aggregate shows the lowest expansion but expansion in excess of $0.1\%$ at 16 days, which can distinguished between deleterious and potentially reactive. Although content of reactive aggregate is a small amount, it can cause detrimental expansion due to alkali-silica reaction.

• Magazine of the Korea Concrete Institute
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• v.6 no.2
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• pp.108-117
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• 1994

This study was performed to investigate the Alkali-Silica Reaction(ASR) of crushed stones using chemical analysis, polarization microscope, XRD, chemical method(KS F 2545, ASTM C 289), mortar-bar method( KS F 2546, ASTM C 227) and Scanning Electron Microscope (SEM ) and Energy Dispersive X-ray Analysis(EDXA) of reaction products by ASK in the mortar bars and to investigate the influence on alkali content and kind of added alkali to the ASR. Test results show that one kind of domestic crushed stone is estimated as deleterious by ASTM chemical method and mortar bar method, and reaction product is proved as alkali silicate gel by EDXA.