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- Englisch (25) (entfernen)
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- LIBS (9)
- Concrete (8)
- Chloride (5)
- Chlorine (4)
- Sulphate (4)
- Heterogeneity (3)
- Beton (2)
- Building materials (2)
- Chloride content (2)
- Depth profiles (2)
Determination of chloride content in concrete structures with laser-induced breakdown spectroscopy
(2003)
Determination of chloride content in concrete structures with laser-induced breakdown spectroscopy
(2005)
An important criterion for the evaluation of reinforced concrete structures is the measurement of the chloride content. This will normally be done by time consuming standard chemical methods. We propose the application of a spectroscopic technique, the laser-induced breakdown spectroscopy (LIBS), which provides the advantages of a fast measurement, the potential for on-site application and the possibility to investigate a wide range of different measuring points. The surface can be scanned, or depth profiles are available from cores. Measurements can be performed directly on the sample surface and the results are available in near real time. We present LIBS results measured on concrete cores as well as on grinded and pressed material in comparison with the results of standard chemical methods. The optimum LIBS set-up and the experimental conditions to detect and measure chlorine in building materials are reported. The limits of detection were determined and calibration curves were measured.
Application of laser induced breakdown spectroscopy for the detection of hydrophobic coatings
(2001)
Laser-induced breakdown spectroscopy for fast analysis of ingress profiles of ions on concrete
(2012)
The Chloride content is an important factor which influences the durability of concrete structures. The standard methods are mostly intricate, time consuming and require a chemical laboratory. This article describes the application of a spectroscopic method, the laser-induced breakdown spectroscopy (LIBS), for the determination of Chloride contents in concrete and mortar specimens. LIBS can be used on-site, needs no sample preparation and is able to investigate rapidly a large number of different measuring points. The LIBS set-up and the experimental conditions to detect Chlorides are reported. Calibration curves are presented and the limit of detection (LOD) is determined. Results measured on different concrete cores are presented and compared with the results of standard chemical methods.
Laser induced breakdown spectroscopy for fast analysis of ingress profiles of ions on concrete
(2012)
Laser Induced Breakdown Spectroscopy (LIBS) is a combination of laser ablation, plasma formation and optical emission spectroscopy. The possibility of direct measurements on the sample surface, the minimum of necessary sample preparation and the automated setup allows for fast investigations of building materials. In combination with a scanning technique (translation stage or scanning mirrors head) the element distribution can be evaluated in consideration of the material's heterogeneity. LIBS measurements are also time-and cost-saving. The ingress profile of chlorine on a 50mm diameter concrete core up to a depth of 50mm can be measured and evaluated in less than 10 minutes. The results are normally referred to the evaporated mass, which is approximately the cement mass of the specific concrete. As a completion to micro XRF measurements also light elements like sodium or hydrogen can be detected. The spatial resolution of the measurement may reach 50 ìm at a maximum measurement frequency of up to 100 Hz. On the basis of calibration curves, results can be quantified.
Our aim is the application of LIBS as a simple, quasi on-line method for the non-destructive testing of concrete. Concrete is naturally inhomogeneous. Therefore we must take into account the local variation of the element composition using a statistical analysis. Depending on how much cement and aggregate is measured with each laser pulse, a scan on the surface of a concrete specimen produces a distribution of points in the Rankin diagram which is used to characterise the concrete.
The high amount of building waste material requires innovative strategies for high-order re-use of the material. With Laser Induced Breakdown Spectroscopy (LIBS) both the elemental composition of building materials and trace elements can be determined with a real-time measurement, even on-site and in a harsh industrial environment. We present the experimental data on heavy metal detection in the ppm concentration range, as well as calibration curves. Further on we demonstrate the characterization of cement and concrete concerning the main components by means of Rankin diagrams. We suggest an implementation of LIBS in the processing of building waste materials to allow a high-order re-use.