The Investigation of Alkali – Silica Reactivity (ASR) of Lithuanian Aggregates

Žvironaitė, Jadvyga; Pranckevičienė, Jolanta

doi:10.1016/j.proeng.2017.02.160

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…Expansion Figure 1 shows the progression of the expansion of the specimens during the 28 days when it was tested according to the AAR-2 test methodology. The results show that, after 21 days in storage, the expansion of all the specimens exceeds the critical values specified in the different sources [13,15,29]. The biggest expansion was observed in the specimens with aggregate J, whereas the specimens with aggregate R had the smallest expansion.…”

Section: Storage In the 1m Naoh Solution At 80 °Cmentioning

confidence: 75%

“…The concrete aggregates from the Lithuania gravel deposits contain about (2 -4 %) reactive silica minerals, mostly rapid reacting opal and a slower reacting cryptocrystalline quartz mineral (flint) [12][13][14]. The reactivity tests with aggregates from different Lithuanian regions [13] conducted in accordance with the RILEM AAR-2.2 method showed that the majority of the investigated aggregates could possibly be attributed to Class II-S according to the RILEM AAR-0 requirements (potentially alkali-reactive) [15] and their expansion values are most often close to the lower limit value. Although these values demonstrate the relatively low reactivity of the aggregates, ASR was found to be very common in the structures made of concrete containing these aggregates before the introduction of the preventive measures.…”

Section: Introductionmentioning

confidence: 99%

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Alkali-Silica Reactivity of Portland-Composite Cements and Gravel Aggregates

Žvironaitė¹

2018

Ceramics - Silikaty

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The potential alkali-silica reactivity (ASR) of various combinations of Portland-composite cements CEM II/A, and Lithuanian aggregates from three gravel deposits are investigated in this work. These aggregates which contain about (2-4 %) reactive siliceous rocks (mostly rapid reacting opal and slower reacting flint) could possibly be assigned to Class II-S (potentially alkali-reactive). Two indicators were used to assess the effectiveness of the supplementary cementing materials (SCMs)slag (S), fly ash (FA) and burnt shale, which are present up to 20 % in the cement: the expansion of the mortar specimens in a hot alkali solution and the intensity of the ASR-caused surface damage in the warm humid environment (60 °C and 100 % RH). The presence of S (~15 %) and FA (10 %, 15 %, 20 %) in the cements decreases the expansion, but no mitigating effect (in the case of S) or even a stimulating effect (in the case of 10 % and 15 % FA) was observed for the ASR-caused surface damage, the effect only occurred in the case of the threshold content (20 %) of FA in the cement. The stimulating effect of burnt shale (~ 18 %) was observed on both the expansion and surface damage. A strong linear correlation (R = 0.95) between the changes in the flexural strength and expansion was observed in the 28-day specimens when tested according to AAR-2.2.

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Section: Storage In the 1m Naoh Solution At 80 °Cmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Alkali-Silica Reactivity of Portland-Composite Cements and Gravel Aggregates

Žvironaitė¹

2018

Ceramics - Silikaty

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“…The Reaction occurs between the reactive Silica (found in specific aggregates with disturbed structure) with the Alkalis present in Cement. The process yields ASR gel that expands variably [5] [6] and engenders map cracking on the surface of Concrete. The Chemistry of Alkali Silica reaction is a complex reaction [6] that is explained through various models.…”

Section: Alkali Silica Reaction-a Brief Chemistrymentioning

confidence: 99%

“…ASR happens because of the Reaction of Silica present in aggregates with Alkalis in the form of OHions present in cement pore solution. This process forms Alkali Silica gel, which expands variably [5] [6] and engenders map cracking on the surface of Concrete. The process takes a significant amount of time before any sign of distress becomes visible [7].…”

Section: Introductionmentioning

confidence: 99%

Determination of Alkali Silica Reactivity (Asr) Potential of Aggregates in Khairpur Region

2022

IRJMETS

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Concrete's durability is affected by a range of factors. Alkali Silica Reaction (ASR) is one of such mechanisms that adversely impacts Concrete's durability and reduces its service life. The Reaction of reactive Silica (present in specific aggregates) and alkalis (present in Cement) begets ASR. The disturbed internal structure of Aggregate has a strong penchant for reactivity. In the presence of moisture, the Reaction produces a hygroscopic gel around the aggregate surface, which absorbs more moisture. As a result, the gel volume increases. The process engenders microcracking in Concrete. It propagates to the surface and takes the shape of 'map cracking'. This research work focuses on assessing the reactivity potential of Coarse Aggregates taken from two quarry sites of Kot Banglo, Khairpur region. The aggregates are washed and crushed. They are tested with Ordinary Portland Cement (OPC). ASTM 1260 test procedure was employed to check the reactivity potential of aggregates. The 14-day expansion of mortar bars (specimen dimension 25mm x 25mm x 285mm) was less than 0.1%. According to ASTM 1260, the result validates the innocuous characteristic of aggregates.

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