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Impact of grain sizes on the quantitative concrete analysis using laser-induced breakdown spectroscopy

  • In civil engineering concrete is the most used building material for making infrastructures like bridges and parking decks worldwide. It is as a porous and multiphase material made of aggregates with a defined grain size distribution, cement and water as well as different additives and admixtures depending on the application. Different grain sizes are important to ensure the needed density and compressive strength. The resulting porous cement matrix contains a mixture of flour grains (aggregates with a grain size below 125 lm) and cement particles (particle size≈50lm). Harmful species like chlorides may penetrate together with water through the capillary pore space and may trigger different damage processes. The damage assessment of concrete structures in Germany is estimated due to the quantification of harmful elements regarding to the cement content only. In the evaluation of concrete using LIBS a two-dimensional scanning is necessary to consider the heterogeneity caused by theIn civil engineering concrete is the most used building material for making infrastructures like bridges and parking decks worldwide. It is as a porous and multiphase material made of aggregates with a defined grain size distribution, cement and water as well as different additives and admixtures depending on the application. Different grain sizes are important to ensure the needed density and compressive strength. The resulting porous cement matrix contains a mixture of flour grains (aggregates with a grain size below 125 lm) and cement particles (particle size≈50lm). Harmful species like chlorides may penetrate together with water through the capillary pore space and may trigger different damage processes. The damage assessment of concrete structures in Germany is estimated due to the quantification of harmful elements regarding to the cement content only. In the evaluation of concrete using LIBS a two-dimensional scanning is necessary to consider the heterogeneity caused by the aggregates. Therefore, a LIBS system operating with a low energy NdCr:YAG laser, a pulse energy of 3 mJ, a wavelength of 1064 nm, a pulse width of 1.5 ns and a Repetition rate of 100 Hz has been used. Different Czerny-Turner spectrometers with CCD detectors in the UV and NIR range have been used for the detection. Large aggregates (macro-heterogeneity) can be excluded from the evaluation, whereas small aggregates in the range of the laser spot size (flour grains) cannot be spatially resolved. In this work the micro heterogeneity caused by flour grains and their impact on the quantification with LIBS will be discussed. To analyze the effect of changing grain sizes and ratios, the ablation behavior has been determined and compared. Samples with defined grain sizes were made and analyzed using LIBS. The grain size distributions were analyzed with laser diffraction (LDA).zeige mehrzeige weniger

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Autor*innen:Cassian GottliebORCiD, Tobias Günther, Gerd Wilsch
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Spectrochimica Acta Part B: Atomic Spectroscopy
Jahr der Erstveröffentlichung:2018
Organisationseinheit der BAM:8 Zerstörungsfreie Prüfung
8 Zerstörungsfreie Prüfung / 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen
Verlag:Elsevier
Jahrgang/Band:142
Erste Seite:74
Letzte Seite:84
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:Concrete; Grain sizes; LIBS; Micro heterogeneity
Themenfelder/Aktivitätsfelder der BAM:Chemie und Prozesstechnik
DOI:10.1016/j.sab.2018.02.004
ISSN:0584-8547
ISSN:0038-6987
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:29.03.2018
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:26.04.2018
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