Scanning electron microscopy/energy dispersive X-ray analysis of type I portland cement pastes containing parachlorophenol

Abstract

Four mixtures of Type I Portland Cement, parachlorophenol (pCP) and water were examined by scanning electron microscopy and energy dispersive x-ray analysis after hydrating 7, 28, and 90 days. All mixtures were prepared with a water/cement weight ratio of 0.4. Weight ratios of pCP/cement were as follows: 0, 0.04, 0.1 and 0.2. Samples were polished and examined for morphological differences and compositional variations. The smoothness of the polished surface was found to increase with hydration time as well as pCP concentration. X-ray dot maps and microprobe analyses indicate an even distribution of pCP within the hydrated cement paste. However, there is an increase in the mean and standard deviation of the Ca+Mg)/Cl atomic ratio with increasing hydration time for all pCP containing specimens. Although this ratio was higher for inclusions than for the matrix, the detection of Cl in the inclusions suggests a possible interaction between pCP and unhydrated clinker.