Print Email Facebook Twitter An alternative approach to estimate the W/C ratio of hardened concrete using image analysis Title An alternative approach to estimate the W/C ratio of hardened concrete using image analysis Author Valcke, S. Nijland, T.G. Larbi, J.A. TNO Bouw en Ondergrond BenO Publication year 2009 Abstract The water cement (w/c) ratio is a typical quality parameter for concrete. The NT Build 361 Nordtest method is a standard for estimating the w/c ratio in hardened concrete and is based on the relationship between the ilc ratio and the capillary porosity in the cement paste. The latter can be estimated using fluorescent light microscopy of concrete thin sections because the capillary porosity is related to the intensity of the fluorescent light in the cement paste. The NT Build 361 method consists of visual comparison of the light intensity in unknown samples with reference samples. The w/c method easily can be automated by image analysis, comparing the fluorescent light intensity histograms of the fluorescent micrographs. However, there are a few problems to be overcome for image analysis to be reliable with respect to wlc ratio. The first limitation is the presence of aggregates and (air) voids, because only the intensity in the cement paste is of interest. A second issue is that the fluorescent light intensity is strongly dependent on the incident light intensity and age of the fluorescent dye. A third issue is the heterogeneity of the cement paste, i.e. local variation of capillary porosity due to local differences in the w/c ratio. In this paper, we propose solutions to these three problems using specific processing methods of the fluorescent images. Subject Architecturew/c ratioconcreteimage analysisfluorescent light microscopy To reference this document use: http://resolver.tudelft.nl/uuid:fd87198c-f89a-4667-9975-64bbc5e9272a TNO identifier 331996 Source I2lh Euroseminar on Microscopy .Applied to Building Materials 15.-19, Seplember 2009, Dorlmund, Germanv, 254-263 Document type conference paper Files To receive the publication files, please send an e-mail request to TNO Library.