Application of laser induced breakdown spectroscopy

  • A big part of the infrastructure is made of concrete, which is a multiphase system made of cement, aggregates, water and pores. Concrete is often used in combination with steel as reinforced concrete. Environmental influences, especially the ingress of harmful ions in combination with the ingress of water, trigger different damage processes which reduce the designed lifetime of a structure. The ingress of chlorides from de-icing salt or sea water leads to corrosion of the reinforcement. In addition, the carbonation of the concrete may trigger the corrosion of the reinforcement. The ingress of alkalis from deicing salts may cause the expansion of the amorphous silica aggregates (alkali-silica reaction) through formation of a swelling gel of calcium silicate hydrate if water is present. The ingress of sulphates may cause spalling of the concrete surface due to ettringite formation. For the standard procedure in civil engineering cores are taken, cut in slices, grinded and the obtainedA big part of the infrastructure is made of concrete, which is a multiphase system made of cement, aggregates, water and pores. Concrete is often used in combination with steel as reinforced concrete. Environmental influences, especially the ingress of harmful ions in combination with the ingress of water, trigger different damage processes which reduce the designed lifetime of a structure. The ingress of chlorides from de-icing salt or sea water leads to corrosion of the reinforcement. In addition, the carbonation of the concrete may trigger the corrosion of the reinforcement. The ingress of alkalis from deicing salts may cause the expansion of the amorphous silica aggregates (alkali-silica reaction) through formation of a swelling gel of calcium silicate hydrate if water is present. The ingress of sulphates may cause spalling of the concrete surface due to ettringite formation. For the standard procedure in civil engineering cores are taken, cut in slices, grinded and the obtained homogenized powder is solved in acid and investigated by standard procedures. BAM has developed the LIBS technique for the 2D evaluation of the chemical composition of concrete. The technique is established for automated laboratory use with high numbers of samples to investigate transport processes of harmful species (Cl-, CO2 , SO4 2-and alkalis) in concrete. Information about ingress depth and the quantitative values are important to estimate the remaining lifetime of the infrastructure. LIBS is a surface technique. To get information about the ingress depth, a drill core has to be taken and cut in the middle. The measurements are carried out at the cross section. The main advantages of LIBS are the direct measurement on the surface of the concrete, fast analysis (sample rate 100 Hz) with a spatial resolution of up to 100 µm, the consideration of the heterogeneity of the concrete and the possibility of automated measurements which save a lot of manpower and time. As an example the investigation of ingress profiles for standard diffusion and migration tests in civil engineering takes hours in comparison to just a few minutes using LIBS. At the same time a 2D-evaluation provides information about hot spots of elemental concentration which may not be found by standard methods. The state of the art of LIBS technique for applications in civil engineering will be presented, including typical results of 2D investigation of concrete in laboratory. The performance is also demonstrated by examples for onsite applications using a mobile LIBS system. The road map to standardization is presented as well.zeige mehrzeige weniger

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Autor*innen:Gerd Wilsch, Cassian GottliebORCiD, Tobias Günther, Steven Millar
Persönliche Herausgeber*innen:Mike Forde
Dokumenttyp:Beitrag zu einem Tagungsband
Veröffentlichungsform:Graue Literatur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Structural Faults + Repair-2018
Jahr der Erstveröffentlichung:2018
Organisationseinheit der BAM:8 Zerstörungsfreie Prüfung
8 Zerstörungsfreie Prüfung / 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen
Herausgeber (Institution):University of Edinburgh, School of Engineering, UK
Verlag:University of Edinburgh
Verlagsort:Edinburgh
Erste Seite:1
Letzte Seite:7
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurbau
Freie Schlagwörter:Chloride; Concrete; LIBS; Sulphate
Themenfelder/Aktivitätsfelder der BAM:Chemie und Prozesstechnik
Infrastruktur
Veranstaltung:Structural Faults + Repair-2018
Veranstaltungsort:Edinburgh, UK
Beginndatum der Veranstaltung:15.05.2018
Enddatum der Veranstaltung:17.05.2018
DOI:10.25084/sfr.2018.0030
ISBN:0-947644-86-5
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:10.12.2018
Referierte Publikation:Nein
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