Publications by authors named "S Sachlova"

Bentonite is an integral part of the engineered barrier system (EBS) in deep geological repositories (DGR) for nuclear waste, but its indigenous microorganisms may jeopardize long-term EBS integrity. To predict microbial activity in DGRs, it is essential to understand microbial reactions to the early hot phase of DGR evolution. Two bentonites (BCV and MX-80) with varied bentonite/water ratios and saturation levels (compacted to 1600 kg.

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As bentonite hosts a diverse spectrum of indigenous microorganisms with the potential to influence the long-term stability of deep geological repositories, it is essential to understand the factors influencing microbial activity under repository conditions. Here, we focus on two factors, i.e.

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Semi-continuous ultrasonic sounding of experimental mortar bars used in the accelerated alkali silica reactivity laboratory test (ASTM C1260) is proposed as a supplementary measurement technique providing data that are highly sensitive to minor changes in the microstructure of hardening/deteriorating concrete mixture. A newly designed, patent pending, heating chamber was constructed allowing ultrasonic sounding of mortar bars, stored in accelerating solution without necessity to remove the test specimens from the bath during the measurement. Subsequent automatic data analysis of recorded ultrasonic signals proved their high correlation to the measured length changes (expansion) and their high sensitivity to microstructural changes.

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Article Synopsis
  • The study analyzed various quartz types from the Czech Republic and Sweden using advanced microscopy techniques and an accelerated mortar bar test to assess their alkali-silica reaction potential.
  • Very fine-grained chert was found to have the highest potential for reactive alkali-silica reactions, indicated by a specific dark red cathodoluminescence emission.
  • In contrast, massive coarse-grained pegmatite quartz showed nonreactive properties with a short-lived blue emission, while fine-grained hydrothermal quartz had increased reactivity potentially due to its structural defects.
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