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Scanning Electron Microscopy of Plasticized Cement Stone After Heat-Moisture Treatment
The use of superplasticizers (SPs) in concrete and mortar mixtures makes it possible to obtain materials with high strength, frost resistance, and water resistance by reducing the water-cement ratio. The most widely used SPs are based on polycarboxylate esters (PCE) and sulfonated naphthalene formaldehydes (SNF). Under the conditions of heat-moisture treatment (HMT), temperature deformations and pores inevitably form in the body of the hardening cement stone. The use of SPs allows you to reduce the size and number of pores, leading to some relaxation of internal stresses in the stone. In particular, the HMT mode is considered without preliminary holding according to the mode (0–6–2) h at a steaming temperature of 60 °C. It is important at the same time to understand which phases are formed during the hardening of cement systems with SP at HMT. Scanning electron microscopy (SEM) analysis allowed us to draw several conclusions. The size of calcium hydrosulfaluminate crystals is much smaller in systems with SP. In particular, in cement stone with SNF, AFt crystals after HMT are significantly shorter, up to 500 nm long, indicating the stone’s loose structure in this period. The length of ettringite crystals in compositions without additives reaches 3 microns. Zones of unreacted CaSO4\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdot$$\end{document}2H2O minerals were recorded in cement stone with the addition of PCE, and the gradual ettringite formation was shown in the contact zone with tricalcium aluminate. The results obtained can be used to develop HMT modes to get high early strength with a shortened steaming duration.
Scanning Electron Microscopy of Plasticized Cement Stone After Heat-Moisture Treatment
The use of superplasticizers (SPs) in concrete and mortar mixtures makes it possible to obtain materials with high strength, frost resistance, and water resistance by reducing the water-cement ratio. The most widely used SPs are based on polycarboxylate esters (PCE) and sulfonated naphthalene formaldehydes (SNF). Under the conditions of heat-moisture treatment (HMT), temperature deformations and pores inevitably form in the body of the hardening cement stone. The use of SPs allows you to reduce the size and number of pores, leading to some relaxation of internal stresses in the stone. In particular, the HMT mode is considered without preliminary holding according to the mode (0–6–2) h at a steaming temperature of 60 °C. It is important at the same time to understand which phases are formed during the hardening of cement systems with SP at HMT. Scanning electron microscopy (SEM) analysis allowed us to draw several conclusions. The size of calcium hydrosulfaluminate crystals is much smaller in systems with SP. In particular, in cement stone with SNF, AFt crystals after HMT are significantly shorter, up to 500 nm long, indicating the stone’s loose structure in this period. The length of ettringite crystals in compositions without additives reaches 3 microns. Zones of unreacted CaSO4\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\cdot$$\end{document}2H2O minerals were recorded in cement stone with the addition of PCE, and the gradual ettringite formation was shown in the contact zone with tricalcium aluminate. The results obtained can be used to develop HMT modes to get high early strength with a shortened steaming duration.
Scanning Electron Microscopy of Plasticized Cement Stone After Heat-Moisture Treatment
Lecture Notes in Civil Engineering
Akimov, Pavel (editor) / Vatin, Nikolai (editor) / Tusnin, Aleksandr (editor) / Doroshenko, Anna (editor) / Leshkanov, Andrei (author) / Dobshits, Lev (author) / Anisimov, Sergey (author)
2022-09-03
11 pages
Article/Chapter (Book)
Electronic Resource
English
Phase Content of Plasticized Cement Systems in the Early Stages of Heat-Moisture Treatment
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