Detailed depth profiles of sulfate ingress into concrete measured with laser induced breakdown spectroscopy

Sulfate attack constitutes a major risk of chemical aggression for concrete and other building materials. Mainly structures exposed to sewage waters and sulfate rich soils are affected. The measurement of sulfate ingress is important for damage assessment previous to repair works and for quality assurance of the effectiveness of protecting coatings or during concrete removal. Laser induced breakdown spectroscopy is introduced for the quantitative measurement of sulfur contents in building materials, providing detailed depth profiles and imaging element distributions with 1 mm spatial resolution. Detailed statistical evaluation is possible due to the spatial resolution and the fast measurement of the method. Practical applications of the method for damage assessment are demonstrated for three different sewage plants. (C) 2008 Elsevier Ltd. All rights reserved.