• International Journal of Highway Engineering
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• v.14 no.6
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• pp.37-43
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• 2012

PURPOSES : This study is to evaluate the feasibility of setting the standard of cement alkali content by using ASTM C 1260(accelerated mortar bar test) METHODS : This study analyzes the ASR(alkali silica reaction) expansion of cement mortar bar based on the changes in the aggregate type(fine, coarse), cement type(ordinary, low alkali), and replacement contents of fly ash. ASR tests were conducted according to ASTM C 1260. RESULTS : In this test results, There is no big difference in the ASR expansion between ordinary cement and low alkali cement. From this test results, it was found that the variation of cement alkali content did not have a effect on ASR expansion because mortar bar was placed in a container with sufficient alkali aqueous solution at high temperature during the test process of ASTM C 1260. CONCLUSIONS : It is evidently clear that the alkali content of cement have a effect on ASR. But ASTM C 1260 is difficult to assess this effect.

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.125-132
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• 2006

Waste glass has been increasingly used in industrial applications. One shortcoming in the utilization of waste glass for concrete production is that it can cause the concrete to be weakened and cracked due to its expansion by alkali-silica reaction(ASR). This study analyzed the ASR expansion and strength properties of concrete in terms of waste glass color(amber and emerald-green), and industrial by-products(ground granulated blast-furnace slag, fly ash). Specifically, the role of industrial by-products content in reducing the ASR expansion caused by waste glass was analyzed in detail. In addition, the feasibility of using ground glass for its pozzolanic property was also analyzed. The research result revealed that the pessimum size for waste glass was $2.5{\sim}1.2mm$ regardless of the color of waste glass. Moreover, it was found that the smaller the waste glass is than the size of $2.5{\sim}1.2mm$, the less expansion of ASR was. Additionally, the use of waste glass in combination with industrial by-products had an effect of reducing the expansion and strength loss caused by ASR between the alkali in the cement paste and the silica in the waste glass. Finally, ground glass less than 0.075 mm was deemed to be applicable as a pozzolanic material.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.577-584
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• 2007

The effect of steel microfibers (SMF) on alkali-silica reaction (ASR) was investigated using two types of reactive aggregates, crushed opal and a pyrex rod of constant diameter. Cracks are less visible in the SMF mortars compared with the unreinforced mortars. Due to crack growth resistance behavior in SMF mortar specimens, the strength loss is eliminated and the ASR products remained well confined within the ASR site. The expansion and the ASR products were characterized by microprobe analysis and inductively coupled plasma (ICP) spectroscopy. The confinement due to SMF resulted in a higher Na and Si ion concentration of the ASR liquid extracted from the reaction site. The higher concentration reduced the ASR rate and resulted in a lower reactivity of the reactive pyrex rods in SMF mortars.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.431-437
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• 2008

The concrete pavement at Seohae Expressway in Korea has suffered from serious distress, only after four to seven years of construction. The deterioration of ASR has seldom been reported per se in Korea, because the aggregate used for the cement concrete has been considered safe against alkali-silica reaction so far. The purpose of this study is to examine the expansion behavior of aggregates of Korea due to alkali-silica reaction by ASTM C 1260 standard method of the accelerated mortar bar test (AMBT), stereo microscopic analysis, scanning electronic microscope (SEM) analysis, and electron dispersive X-ray spectrometer (EDX) analysis. The results are presented as it follows. The accelerated mortar bar test (AMBT) showed that mica granite and felsite of igneous rocks, aroke, red sandstone and shale of sedimentary rocks, slate of metamorphic rock, and dendrite and quartz of mineral rock showed more expansion than 0.1% at 14 days. But, some sedimentary rocks and metamorphic rocks expanded more than 0.1% at 28 days even though they were less than 0.1% at 14 days. The mortar bars, which showed more than occurred 0.1% expansion, resulted in cracking on surface. SEM and EDX analysis confirmed that the white gel was a typical reaction product of ASR. The ASR gel in Korea mainly consisted of Silicate (Si) and Potassium (K) from the cement. The crack in the concrete pavement was caused by ASR. It seems that Korea is no longer safe zone against alkali-silica reaction.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.305-312
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• 2013

This paper reports the results of an investigation into the effects of silica fume on strength properties of alkali-activated slag cement (AASC) with water-binder (W/B) ratio and replacement ratio of silica fume content. The W/B ratio varied between 0.50 and 0.60 at a constant increment of 0.05. The silica fume content varied from 0% to 50% by weight of slag. The activators was used sodium hydroxide (NaOH) and the dosage of activator was 3M. The strength development with W/B ratio has been studied at different ages of 1, 3, 7 and 28 days. For mixes of AASC mortars with varying silica fume content, the flow values were lower than the control mixes (without silica fume). The flow value was decrease as the content of silica fume increase. This is because the higher surface areas of silica fume particles increase the water requirement. The analysis of these results indicates that, increasing the silica fume content in AASC mortar also increased the compressive strength. Moreover, the strength decreases with the W/B ratios increases. This is because the particle sizes of silica fume are smaller than slag. The high compressive strength of blended slag-silica fume mortars was due to both the filler effect and the activated reaction of silica fume evidently giving the mortar matrix a denser microstructure, thereby resulting in a significant gain in strength.

• Advances in concrete construction
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• v.11 no.4
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• pp.299-306
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• 2021

The alkali-silica reaction (ASR) is a highly complex chemical reaction which causes damage to concrete and thus adversely affects the durability and service life. Significant damage can occur in concrete structures due to cracking because of the chemical reactions taking place. Various mineral and chemical additives have been used so far to mitigate ASR and/or to reduce its adverse effects. In this study, ground trachyte and rhyolite provided from Rize-Çağrankaya region, Turkey, were used to investigate their effectiveness in controlling ASR-induced damage by substituting them with cement at certain ratios. In this context, initially the possible use of trachyte and rhyolite as pozzolanas was determined in accordance with BS EN 450-1 and TS 25 standards by considering their pozzolanic activities and then their effectiveness in mitigating the ASR was evaluated as per ASTM C 1567-13. In experimental study, blends of trachyte and rhyolite were prepared by substituting them by cement at 25%, 35%, and 50% percentage. Totally 7 mixes were prepared and three samples of 25×25×285 mm mortar bars were prepared from each batch. The length changes of the mortar bars were determined at the end of 3, 7, 14 and 28 days of exposure. SEM, along with XRD analyses were performed to examine and elementally determine the ASR products that have been formed. The results obtained have shown that ground trachyte and rhyolite used in this study can be used as pozzolanas in concrete and they can also significantly mitigate ASR-induced damage as the substitution ratio increases.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.1-6
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• 2011

The possibility of ASR(alkali-silica reaction) for coarse aggregates had known to be low up to recently in Korea. But the distress of ASR was identified and reported by ASTM C 1260 test. The purpose of this paper was to identify the effect of environmental conditions on length expansion of mortar-bar by alkali-silica reaction with KS F 2546 and ASTM C 1260 test. The results of this study were as following; The result of KS F 2546 test for five kinds of aggregates shows that all of them are non-reactive. But that of ASTM C 1260 test shows that all of aggregates except Andesite-2 are over possible reactive because of environmental condition such as external alkali ion by 1N NaOH, high temperature and humidity. The result of variety of NaOH concentration on ASTM C 1260 using Siltstone indicates that length expansion rate increases highly as NaOH concentration increases. And, comparison results of KS F 2546 for Siltstone with that of 0.00N NaOH experiment indicates that length expansion rate increases as temperature and humidity increases.

• Computers and Concrete
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• v.22 no.1
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• pp.1-10
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• 2018

In this study an implicit algorithm for modeling of propagation of macrocracks in 3D concrete structures suffering from alkali-silica reaction has been developed and implemented. The formulation of the problem prior to the onset of localized deformation is based on a chemo-elasticity approach. The localized deformation mode, involving the formation of macrocracks, is described using a simplified form of the strong discontinuity approach (SDA) that employs a volume averaging technique enhanced by a numerical procedure for tracing the propagation path in 3D space. The latter incorporates a non-local smoothening algorithm. The formulation is illustrated by a number of numerical examples that examine the crack propagation pattern in both plain and reinforced concrete under different loading scenarios.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.541-544
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• 2006

This study was performed to proof expansion effect of the mortar bar due to Alkali-silica Reaction (ASR) by ASTM C 1260 test. Recently, the failure case of cement concrete pavement by ASR was reported in Korea. Cement concrete structures are caused crack by ASR. The service life of cracked cement concrete structures by ASR will be shorted. In this study, crushed the slate rock producted Chungcheongnamdo Boryeong was caused 0.3% expansion at 14 days due to ASR by ASTM C 1260 test. The particular spectrum showed that the ASR gel was analyzed contents included Si, Na, K, and Ca by EDX (electron dispersive X-ray spectrometer). It was verified that the crushed aggregate was caused expansion by ASR in Korea.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.195-196
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• 2023

In this study, the mechanical properties, alkali-silica reaction(ASR) expansion and residual mechanical properties after ASR of waste glass fine aggregate(GS) mortar according to mineral mixture were evaluated. As a result, it was found that the mineral mixture reduces the ASR expansion. However, mechanical properties and residual mechanical properties have decreased.