Formation and characterization of ceramic coating from alumino silicate mineral powders in the matrix of cement composite on the concrete wall

Enhancement of thermal performance of concrete wall is nowadays of great importance in reducing the operational energy demand of buildings. We developed a new kind of inorganic coating material based on \ce{SiO2}-\ce{Al2O3}-rich minerals and Portland cement (PC) powder. The finely pulverized mineral...

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Bibliographic Details
Published in:arXiv.org 2019-01
Main Authors: Chol-Jun Yu, Ri, Byong-Hyok, Chung-Hyok, Kim, Un-Song Hwang, Kum-Chol Ri, Chang-Jin, Song, Kim, Un-Chol
Format: Article
Language:English
Subjects:
Aluminum oxide
Calcium aluminum silicates
Calcium silicate hydrate
Ceramic coatings
Ceramic glazes
Ceramic powders
Ceramics
Chemical composition
Composite materials
Concrete
Fuel consumption
Inorganic coatings
Minerals
Morphology
Mortars (material)
Organic chemistry
Particle size distribution
Porosity
Portland cements
Protective coatings
Scanning electron microscopy
Silicon dioxide
Slaked lime
Weight
X ray powder diffraction
X-ray diffraction
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Summary:Enhancement of thermal performance of concrete wall is nowadays of great importance in reducing the operational energy demand of buildings. We developed a new kind of inorganic coating material based on \ce{SiO2}-\ce{Al2O3}-rich minerals and Portland cement (PC) powder. The finely pulverized mineral powder with the particle size distribution (PSD) of 0.4-40 \(\mu\)m was mixed with the vehicle solvent containing some agents, cement powder with PSD of 2-100 \(\mu\)m, and water in the certain weight ratio, producing the colloid solution. After application within 2 hours to the plaster layer of concrete wall and sufficient long hardening period of over three months, the coating layer of 0.6-1.0 mm thickness was observed to become a densified ceramic. Powder X-ray diffraction (XRD) experiments were performed to identify the crystalline components of minerals, cement and ceramic coating powders. Three- and two-dimensional surface morphologies and chemical compositions of coating material were obtained with the optical interferometer and scanning electron microscope (SEM) equipped with an energy dispersive X-ray analyzer (EDX). These XRD and SEM/EDX analyses demonstrated obviously that the coating layer is mainly composed of the calcium-silicate-hydrate (C-S-H) and the calcium-aluminate-hydrate (C-A-H) ceramics with the relatively small number of closed pores (10\% porosity) compared with the cement mortar and concrete layers. Two-step hydrations of cement and subsequently \ce{SiO2}-\ce{Al2O3} promoted by the alkali product \ce{Ca(OH)2} were proposed as the main mechanism of ceramic formation.
ISSN:2331-8422