| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Paegle, Ieva
Technical University of Denmark
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (11/11 displayed)
- 2019Optical sensing of ph and o 2 in the evaluation of bioactive self-healing cementcitations
- 2019Optical sensing of ph and o2 in the evaluation of bioactive self-healing cementcitations
- 2016Cracking and load-deformation behavior of fiber reinforced concrete: Influence of testing methodcitations
- 2016Phenomenological interpretation of the shear behavior of reinforced Engineered Cementitious Composite beamscitations
- 2015Characterization and modeling of fiber reinforced concrete for structural applications in beams and plates
- 2014Influence of bending test configuration on cracking behavior of FRC
- 2013Evaluation of test methods used to characterize fiber reinforced cementitious composites
- 2012Shear crack formation and propagation in fiber reinforced cementitious composites (FRCC)
- 2011Shear crack formation and propagation in fiber reinforced cementitious composites (FRCC)
- 2011Shear crack formation and propagation in reinforced Engineered Cementitious Composites
- 2010Shear behavior of reinforced Engineered Cementitious Composites (ECC) beams
Places of action
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article
Optical sensing of ph and o2 in the evaluation of bioactive self-healing cement
Abstract
<p>Leakage from cementitious structures with a retaining function can have devastating environmental consequences. Leaks can originate from cracks within the hardened cementitious material that is supposed to seal the structure off from the surrounding environment. Bioactive self-healing concretes containing bacteria capable of microbially inducing CaCO<sub>3</sub> precipitation have been suggested to mitigate the healing of such cracks before leaking occurs. An important parameter determining the biocompatibility of concretes and cements is the pH environment. Therefore, a novel ratiometric pH optode imaging system based on an inexpensive single-lens reflex (SLR) camera was used to characterize the pH of porewater within cracks of submerged hydrated oil and gas well cement. This enabled the imaging of pH with a spatial distribution in high resolution (50 μm per pixel) and a gradient of 1.4 pH units per 1 mm. The effect of fly ash substitution and hydration time on the pH of the cement surface was evaluated by this approach. The results show that pH is significantly reduced from pH >11 to below 10 with increasing fly ash content as well as hydration time. The assessment of bioactivity in the cement was evaluated by introducing superabsorbent polymers with encapsulated Bacillus alkalinitrilicus endospores into the cracks. The bacterial activity was measured using oxygen optodes, which showed the highest bacterial activity with increasing amounts of fly ash substitution in the cement, correlating with the decrease in the pH. Overall, our results demonstrate that the pH of well cements can be reliably measured and modified to sustain the microbial activity.</p>