Print Email Facebook Twitter Effect of natural carbonation on the pore structure and elastic modulus of the alkali-activated fly ash and slag pastes Title Effect of natural carbonation on the pore structure and elastic modulus of the alkali-activated fly ash and slag pastes Author Nedeljković, Marija (TU Delft Materials and Environment) Šavija, B. (TU Delft Materials and Environment; TNO) Zuo, Y. (TU Delft Materials and Environment) Lukovic, M. (TU Delft Concrete Structures) Ye, G. (TU Delft Materials and Environment; Universiteit Gent) Date 2018-02-10 Abstract The aim of this paper was to investigate the effect of natural carbonation on the pore structure, and elastic modulus (Em) of alkali-activated fly ash (FA) and ground granulated blast furnace slag (GBFS) pastes after one year of exposure in the natural laboratory conditions. The chemical changes due to carbonation were examined by X-ray diffraction (XRD), scanning electron microscope/energy-dispersive X-ray (SEM−EDX) and attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR). Subsequently, the pore structure and Em of the degraded material were tested by mercury intrusion porosimetry (MIP), nitrogen (N2) adsorption, and nanoindentation. The chemical degradation of alkali-activated pastes due to natural carbonation is showed to be dependent on the GBFS content and their pore structure development. It was found that the pure alkali-activated GBFS paste was not carbonated at all within the tested period due to fine gel pore structure. On the other hand, carbonation of the gel in the pastes consisting FA and GBFS generated significant mineralogical and microstructural changes. The extensive decalcification of the gel was reflected in the increase of nanoporosity. Consequently, the Em of the carbonated pastes decreased. This study suggests that the degradation of alkali-activated FA and GBFS pastes due to carbonation may be accurately evaluated through micromechanical properties measurements rather than only by testing alkalinity of the pore solution and corrosion of reinforcement such as commonly studied carbonation effect in the ordinary Portland cement (OPC)-based materials. Subject Alkali-activated FA/GBFSENanoindentationNatural carbonationPore structure To reference this document use: http://resolver.tudelft.nl/uuid:433d53e4-f151-4365-9b56-220c5fb9fdfe DOI https://doi.org/10.1016/j.conbuildmat.2017.12.005 Embargo date 2019-12-12 ISSN 0950-0618 Source Construction and Building Materials, 161, 687-704 Part of collection Institutional Repository Document type journal article Rights © 2018 Marija Nedeljković, B. Šavija, Y. Zuo, M. Lukovic, G. Ye Files PDF Final_manuscript_Nedeljko ... et_al..pdf 5.09 MB Close viewer /islandora/object/uuid:433d53e4-f151-4365-9b56-220c5fb9fdfe/datastream/OBJ/view