Abstract

Modern high-performance concrete (HPC) is one of the most versatile, durable, and cost effective building materials known to man. Its composition has been well-characterized in 'test sample' reports from laboratory specimens and trial castings: however, its internal structure often reveals large differences from that of 'test sample concrete'. Moreover, the test procedure is considered destructive. To resolve specific problems related to global urban environmental indicators, a new approach, including methods for near-real-time analysis and vast coverage, is required. The use of reflectance spectroscopy across the visible near- and short-infrared spectral region (400 to 2500 nm) was suggested as a tool to assess the status of concrete in situ. To examine this technique's potential, several controlled experiments were conducted in which concrete was spectrally measured after applying several treatments, including use of different matrix components and post-curing, ageing and corrosion processes. More than 3000 collected samples revealed that spectral measurement combined with spectral analysis tools provides significant and accurate information on the concrete's status. The spectral models were applied to spatial information obtained using a ground image spectrometer. It was concluded that the suggested tool provides near-real-time information on concrete status and might serve as an innovative application in civil engineering.

Key words: High-performance concrete, hydration, curing, hardening, diffuse reflectance spectroscopy, spectral model.