Laser Ablation-Inductive Coupled Plasma- Mass Spectrometry (LA-ICP-MS) put forward much merits like spatially resolved measurements on macroscopic samples, or multi-element analyses with low detection limit in a short time. Although many advantages, the LA-ICP-MS is not immensely employed in building materials area. We applied LA-ICP-MS as a method for examining the Interfacial Transition Zone (ITZ) in concrete. ITZ describes the zone between aggregate and cement paste. According to literature, ITZ has significantly higher porosity and contains more calcium hydroxide as hardened cement paste, with high impact on the mechanical properties and the durability of concrete.
The aim of this work is to develop an optimal strategy to evaluate the LA-ICP-MS results of such a heterogeneous material for a quantitative interpretation, in an attempt to have a deeper look at the ITZ in concrete structures. For our research special cement paste prisms (4x4x16cm) with different water/cement (w/c) ratios and aggregate dices (0,5x0,5x0,5mm; calcite, dolomite or granite) were prepared. The positions of the dices in the prisms were accidentally. To set down the position of the dices in the prisms, we conducted CT measurements. Knowing the dices positions it was possible to cut the prisms in the middle of every dice with a precision saw. Furthermore, for every w/c ratio reference cement paste prisms lacking of dices were prepared. After 28 day, those prisms were grinded in a ball mill. Short behind compressed pellets with aggregate dices were prepared with an automatic press. These pellets should serve as reference material without an ITZ between hardened cement paste and aggregate. All samples were vacuum dried by 40o. During the measurements, we will focus on the setting parameter as fluence, spot type or selection of major and minor elements, to gain a closer look on the ITZ between aggregate and cement paste.
With obtained results, we will investigate the variation between disturbed and non-disturbed hardened cement paste. We will spotlight, if the sample preparation impacts the signal detection from LA-ICP-MS. Crucial element of LA-ICP-MS measurement is the calibration strategy, especially in our case with varying material with very different ablation behavior [1]. The most adequate calibration strategy for our results will be internal standardization over the sum of all oxides and water to 100%. We will focus on enhancement of calibration strategy especially, when the laser ablates different material in one shot. Details of the project and first results will be shown on our poster.
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Laser Ablation-Inductive Coupled Plasma- Mass Spectrometry (LA-ICP-MS) put forward much merits like spatially resolved measurements on macroscopic samples, or multi-element analyses with low detection limit in a short time. Although many advantages, the LA-ICP-MS is not immensely employed in building materials area. We applied LA-ICP-MS as a method for examining the Interfacial Transition Zone (ITZ) in concrete. ITZ describes the zone between aggregate and cement paste. According to literature,...
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