Role of solution concentration, cement alkali and test duration on expansion of accelerated mortar bar test (AMBT)

Islam, Mohammad S.; Alam, M. Shahria; Ghafoori, Nader; Sadiq, Rehan

doi:10.1617/s11527-015-0626-2

Cited by 10 publications

(5 citation statements)

References 29 publications

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“…The results from the ASTM C1293 test confirm observations made by Islam et al [46]. They showed that the mortar bars with hematite/magnetite submerged in 1 M NaOH expanded mostly during the early state of testing up to 28 days, and the expansion rate decreased with an increase in test duration.…”

Section: Discussionsupporting

confidence: 88%

Alkali-Silica Reactivity of High Density Aggregates for Radiation Shielding Concrete

et al. 2018

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Long-term exposure of concrete to nuclear reactor environments may enhance the ageing phenomena. An investigation concerning a possible deleterious alkali-silica reaction (ASR) in concrete containing high-density aggregates is presented in this paper. The scope of this investigation was limited to heavy aggregates that could be used for the construction of the first Polish nuclear power plant (NPP). Five different high-density aggregates were selected and tested: three barites, magnetite, and hematite. Mineralogical analysis was conducted using thin section microscopic observation in transmitted light. The accelerated mortar beam test and the long-time concrete prism test were applied to estimate the susceptibility of heavy aggregates to ASR. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were conducted on aggregates and mortars. The quartz size in aggregate grains was evaluated using image analysis. Application of the accelerated mortar beam method confirmed the observations of thin sections and XRD analysis of high-density aggregates. The microcrystalline quartz in hematite aggregate and cristobalite in one of barite aggregate triggered an ASR. The composition of ASR gel was confirmed by microscopic analysis. The long-term concrete test permitted the selection of innocuous high-density aggregates from among the other aggregates available, which showed practically no reactivity.

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Section: Discussionsupporting

confidence: 88%

Alkali-Silica Reactivity of High Density Aggregates for Radiation Shielding Concrete

et al. 2018

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“…Similar observations have been reported in previous research. For example, Islam et al [75] studied the role of solution concentration on expansion of accelerated mortar bar test by considering three variables i.e., 0.25 N, 0.5 N, and 1.0 N solution concentration. In the case of 0.25, it was observed that mortar expansion was very low compared to identical specimens exposed to 0.5 N and 1.0 N. It was also observed that mortar bar submerged in 0.5 N solution expanded slowly with an increase in test duration; mortar bars placed in 1.0 N solution showed higher expansion during the early age of testing and after 28 days' expansion rate was reduced.…”

Section: Effect Of Solution Concentrationmentioning

confidence: 99%

“…For instance, Tosun and Felekoglu [78] observed the effect of total alka cement on expansion caused by the ASR in mortar bars containing admixtu al. [75] investigated the effect of cement alkalis on mortar bar expansion de solution concentration NaOH and test duration. A higher rate of expansion w It was also observed that the cement alkali contents had a significant influence for specimens exposed to 0.5 N and 1.5 N solution concentration.…”

Section: Effect Of Cement Alkalismentioning

confidence: 99%

“…For instance, Tosun and Felekoglu [78] observed the effect of total alkali content of cement on expansion caused by the ASR in mortar bars containing admixtures. Islam et al [75] investigated the effect of cement alkalis on mortar bar expansion dependent on solution concentration NaOH and test duration. A higher rate of expansion was noted for low concentration of solution NaOH and at early test duration, while the effect was minor for higher solution concentration NaOH and at a later stage of testing.…”

Section: Effect Of Cement Alkalismentioning

confidence: 99%

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Alkali–Silica Reactivity Potential of Reactive and Non-Reactive Aggregates under Various Exposure Conditions for Sustainable Construction

et al. 2023

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The alkali–silica reaction (ASR) is a primary cause for premature concrete degradation. An accelerated mortar bar test is often used to access the detrimental phenomena in concrete caused by the ASR of aggregates. However, this test requires a certain environmental conditioning as per ASTM C1260. The objective of this study is to explore the effects of the cement alkali content, exposure solution concentration, temperature, and test duration on mortar bar expansion. Factorial experimental design and analysis was conducted to delineate the effects of the individual factors as well as their interaction. Five different aggregates with various mineralogical properties were used, representing reactive and non-reactive aggregates. Various dosages of cement alkalis (0.40, 0.80, and 1.20 Na2Oe), sodium hydroxide (NaOH) solution concentrations (0.5, 1.0, and 1.5 N), and temperature (40 °C, 80 °C, and 100 °C) were the studied variables. Mortar bar expansion was measured at 3, 7, 14, 21, 28, 56, and 90 days. Mortar bars incorporating Jhelum aggregates incurred expansion of 0.32% at 28 days, proving to be reactive aggregates as per ASTM C1260. Similarly, specimens incorporating Taxila aggregates showed expansion of 0.10% at 28 days, indicating non-reactive nature. It was observed that specimens with Sargodha aggregates showed expansion of 0.27% at 28 days for 0.50 N NaOH solution concentration compared to 0.31% expansion for identical specimens exposed to 1.5 N solution. Moreover, expansion increased with exposure duration for all the tested specimens. Experimental results showed that the cement alkali contents had relatively lesser effect on expansion for 1.0 N NaOH; while, in the case of 0.5 N and 1.5 N NaOH, the cement alkali had a significant effect. It was noted that expansion increased with an increase in the temperature. Jhelum aggregates showed 28-day expansion of 0.290% when exposed to 40 °C, but at a temperature of 100 °C, expansion increased to 0.339%. Factorial analysis revealed that the exposure solution had a major contribution towards the expansion of mortar bar specimens. This study highlights the contribution of various exposure conditions on the ASR expansion, which leads to a decisive role in selecting the aggregate sources for various applications and exposure conditions leading to sustainable construction.

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“…The reactivity of the volcanic rocks comes from the interstitial material of low crystallinity: volcanic glass and/or mesostasis [14][15][16]. After characterizing the rocks selected for the study (item II), the mesostasis analysis was conducted.…”

Section: A Interstitial Matter Analysismentioning

confidence: 99%

Alkali-Aggregate Reaction: A study of the influence of the petrographic characteristics of volcanic rocks

Bonsembiante

Gomes

Molin

2018

Eng. Technol. Appl. Sci. Res.

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When the rock involved in the alkali-aggregate reaction (AAR) is volcanic, the matter present in the interstices of the grains, called mesostasis is considered responsible for the expansions. Mesostasis is a residue which consists of mineral phases rich in silica and alkalis (K and Na) and in optical microscopy looks like amorphous matter. By means of scanning electron microscopy (SEM) and with the aid of energy dispersive spectroscopy (EDS), the presence of well-crystallized mineral phases in mesostasis can be observed. The objective of this study was to evaluate the amount, the chemical composition and the degree of crystallinity of mesostasis on the reactive potentiality of volcanic rocks.

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Role of solution concentration, cement alkali and test duration on expansion of accelerated mortar bar test (AMBT)

Cited by 10 publications

References 29 publications

Alkali-Silica Reactivity of High Density Aggregates for Radiation Shielding Concrete

Alkali-Silica Reactivity of High Density Aggregates for Radiation Shielding Concrete

Alkali–Silica Reactivity Potential of Reactive and Non-Reactive Aggregates under Various Exposure Conditions for Sustainable Construction

Alkali-Aggregate Reaction: A study of the influence of the petrographic characteristics of volcanic rocks

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