Diffraction-enhanced computed tomography of cement pastes: 3D imaging of the nucleation processes

• 作 者: ArtioliG.[1]ValentiniL.[1]VoltoliniM.[2]DalconiM.C.[1]FerrariG[3]RussoV[3]
• 机 构: Department of Geosciences and CIRCe Centre, University of Padova, Padova 1-35131, Italy
• 出 处: The 14th International Congress on the Chemistry of Cement (
• 发表日期: 2015年期

　　The properties of cementitious materials are related to the microstructure of their binder matrix, which forms by a sequence of dissolution-precipitation reactions converting the clinker phases into hydrates, among which the main hydration product is calcium silicate hydrate (C-S-H).Here, we monitor non-invasively the evolution of the cement paste microstructure during hydration by "pencil beam" synchrotron X-ray diffraction-enhanced computed micro-tomography (XRD-CT).This innovative technique yields phase-resolved images of the hydrating cement paste at different stages, which are combined to map the sites where dissolution and precipitation processes occur.The results indicate that the nucleation mechanism of C-S-H changes when cement hydrates in the presence of poly-carboxylate ether (PCE) superplasticizers, which are commonly used to control the paste rheology.The observed change is essential to understand the development of the cement microstructure and to provide a direct link between the reaction kinetics and the physico-mechanical properties of the system.