Fig. 3From: Carbonation of Portland Cement Studied by Diffuse Reflection Fourier Transform Infrared SpectroscopyIntegrated peak areas for unhydrated and hydrated samples exposed to ambient air as a function of exposure time. The integration range was 1,300–1,700 cm−1 (marked as dotted lines in Fig. 2), where the zero-level was set at 1,300 cm−1.The sample exposed for 10 min was used as reference for each hydration time.Back to article page