Mineralogical and microstructural alterations in a portland cement paste after an accelerated decalcification process
نویسندگان
چکیده
Cement paste leaching and concomitant decalcification is a common cause of concrete structure deterioration. Such alterations entail microstructural changes that condition durability. This study analysed those in cement pastes exposed to accelerated decalcification, layer-by-layer, from the surface contact with agent, 6 M NH4NO3, unaltered area. The were BSEM, MIP BET whilst mineralogical nanostructural each layer assessed XRD, FTIR, 29Si 27Al MAS NMR BSD. Decalcification affected not only portlandite CSH gel, but also anhydrous clinker ettringite, inducing major micro- nano-structural changes, particularly two layers closest agent. gel was more intense outer where long chain gels co-existed silicon rich gels. BDS, turn, revealed differences between amount bound water interfacing agent front. More specifically, larger numbers molecules tightly silanol groups outer, whereas hydroxyl group distribution orderly inner layers.
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ژورنال
عنوان ژورنال: Cement and Concrete Research
سال: 2021
ISSN: ['0008-8846', '1873-3948']
DOI: https://doi.org/10.1016/j.cemconres.2020.106312