Acoustic emission monitoring of crack formation during alkali silica reactivity accelerated mortar bar test

Lokajı́ček, T.; Přikryl, Richard; Šachlová, Šarka; Kuchařová, Aneta

doi:10.1016/j.enggeo.2017.02.009

Cited by 16 publications

(4 citation statements)

References 42 publications

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“…However, it was applied only seldom for characterising damage processes due to ASR [36][37][38]. Again, ultrasonic pulse velocity in concrete specimens is commonly measured to characterise ASR-induced damage [1].…”

Section: Methodsmentioning

confidence: 99%

Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models

et al. 2018

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The susceptibility of concrete structures due to alkali-silica reaction (ASR) can be assessed by means of ASR concrete prism testing at 60°C, according to RILEM AAR 4.1. There, expansion of concrete prisms indicates alkali-reactivity of the examined concrete mix. This work applies in situ expansion measurement to accelerated concrete prism testing. Automated measuring facilitates both storage without the usually necessary interruptions for manual measurement and acquisition of quasi-continuous expansion data. A comparative experimental programme showed that conventional testing resulted in stronger expansion and leaching of alkalis than automated testing. Experimental simulation of interruptions, typically associated with manual measurements in conventional testing, could prove the influence of these cooling-heating cycles. Two phenomenological approaches, frequently used for describing reaction kinetics of ASR by linking it to expansion results from ASR-testing, were validated with continuous expansion data of three types of aggregate. Experimental expansion depicted s-shaped curves similar to them of the modelling approaches. However, strong swelling recorded in the beginning of the test was not covered by the model curves. Auxiliary measurement of acoustic emissions and ultrasonic velocity helped characterising mechanisms such as hydration and cracking, which also influence prism expansion. The proposed modification of the measurement procedure provides an extended basis to analyse expansion mechanisms. Regarding data for validation of ASR-expansion models, continuous expansion results are preferable to conventional test results.

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Section: Methodsmentioning

confidence: 99%

Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models

et al. 2018

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“…The emission method was adapted to measurements of alkali corrosion in rock and concrete samples, conducted primarily under laboratory conditions, fairly recently, in the second decade of the 21 st century. The tests were conducted on specimens of mortars with reactive aggregate, using the accelerated testing methodology in accordance with ASTM C1260, and concrete specimens in accordance with ASTM C1293 [35][36][37]. The results of the analyses indicated that AE enabled the detection of early ASR cracking of concrete; at later test stages, particularly with an increased degree of cracking and gel formation, elastic wave attenuation was observed [38].…”

Section: Introductionmentioning

confidence: 99%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Świt¹,

Zapała-Sławeta²

2020

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The study presented research on the possibility of using acoustic emission to detect and analyze the development of the alkali-silica reaction (ASR) in cement mortars. The experiment was conducted under laboratory conditions using mortars with reactive opal aggregate, accelerating the reaction by ensuring high humidity and temperature, in accordance with ASTM C227. The progress of corrosion processes was monitored continuously for 14 days. The tests were complemented with measurements of the expansion of the mortars and observations of microstructures under a scanning electron microscope. The high sensitivity of the acoustic emission method applied to material fracture caused by ASR enabled the detection of corrosion processes already on the first day of the test, much sooner than the first recorded changes in linear elongation of the specimens. Characteristic signal descriptors were analyzed to determine the progress of corrosion processes and indicate the source of the cracks. Analysis of recorded 13 AE parameters (counts total, counts to peak, duration, rise time, energy, signal strength, amplitude, RMS, ASL, relative energy, average frequency, initial frequency and reverberation frequency) indicates that the number of counts, signal strength and average frequency provide most information about the deleterious processes that occur in the reactive aggregate mortars. The values of RA (rise time/amplitude) and AF (average frequency) enabled the classification of detected signals as indicating tensile or shear cracks. The acoustic emission method was found suitable for monitoring the course of alkali-aggregate reaction effects.

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“…However, the correlation with damage in the field was small. Lokajicek et al stated that out of the nondestructive methods based on the development of brittle damage related to internal stresses, the acoustic emission method seemed to be the most adequate method for tests of the alkali–aggregate reaction [19]. They based this statement on a large number of tests concerning the detection of brittle fracture in rocks exposed to loads and concrete [20,21].…”

Section: Introductionmentioning

confidence: 99%

“…The cracks were caused by the formation of expansive reaction products. The effectiveness of this method was also confirmed during the monitoring of the alkali–aggregate reaction [17,19,27,28]. The acoustic emission method, however, has not been used to analyse the effectiveness of corrosion inhibitors.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

Zapała-Sławeta

Świt

2018

Materials

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The study analyzed the possibility of using the acoustic emission method to analyse the reaction of alkali with aggregate in the presence of lithium nitrate. Lithium nitrate is a chemical admixture used to reduce adverse effects of corrosion. The tests were carried out using mortars with reactive opal aggregate, stored under the conditions defined by ASTM C227. The acoustic activity of mortars with a corrosion inhibitor was referred to linear changes and microstructure of specimens in the initial reaction stages. The study found a low acoustic activity of mortars with lithium nitrate. Analysis of characteristic parameters of acoustic emission signals, combined with the observation of changes in the microstructure, made it possible to describe the corrosion processes. As the reaction progressed, signals with different characteristics were recorded, indicating aggregate cracking at the initial stage of the reaction, followed by cracking of the cement paste. The results, which were referred to the acoustic activity of reference mortars, confirmed that the reaction of opal aggregate with alkali was mitigated in mortars with lithium nitrate, and the applied acoustic emission method enabled the detection and monitoring of ASR progress.

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Acoustic emission monitoring of crack formation during alkali silica reactivity accelerated mortar bar test

Cited by 16 publications

References 42 publications

Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models

Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models

Bulletin of the Polish Academy of Sciences: Technical Sciences

Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

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