نتایج جستجو برای: portland cement dust
تعداد نتایج: 71627 فیلتر نتایج به سال:
Recently, modern techniques have been applied for analysis of the influence of polymers on microstructural properties of Portland cement, such as Thermogravimetric Analyses (TG), Scanning Electronic Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and Mercury Intrusion Porosimetry (MIP). In this study, thermogravimetric analyses were used to study the influence of vinyl acetate...
Portland cement for high-temperature geothermal applications typically includes 35 to 40 percent crystalline quartz by weight of cement (BWOC) to avoid strength retrogression, which is defined as an increase in permeability and a decrease in compressive strength. Also, because of the reactivity of Portland cement at elevated temperatures, relatively expensive cement-hydration retarders are requ...
Cement-based materials have often been used for infrastructure construction and repair. The production of conventional Portland cement is energy-consuming and environmentally unfriendly. For example, production of one ton of Portland cement generates approximately one ton of carbon dioxide (CO 2 ) from calcining limestone and fuel use. It is estimated that cement production contributes 7% of to...
Copolymer latexes based on 2-hydroxy ethyl acrylate (2-HEA) and 2-hydroxy ethylmethacrylate (2HEMA) were synthesized with different molar ratios (95/ 05, 90/10 and 85/15) using azo-bisisobutyronitril(ABIN) as initiator and alcoholic solution as solvent. Different molar ratios of monomers was designed to investigate the effect of latexes on the physico-mechanical properties of Portland cement mo...
We have studied the rheological property evolution and hydration behavior of white and ordinary portland cement (type I) pastes and concentrated cement–polyelectrolyte suspensions. Cement composition had a marked effect on the elastic property evolution (G (t)) and hydration behavior of these suspensions in the presence of poly(acrylic acid)/poly(ethylene oxide) copolymer (PAA/PEO), even though...
statement of problem: mineral trioxid aggregate (mta) cement is widely used for root-end filling, pulp capping, perforation repair and other treatments in endodontics. investigations have shown similar physical and chemical properties for portland cement (type i), root mta and proroot mta. purpose: the aim of this in vivo study was to evaluate the reaction of dog canine pulp after pulp capping ...
statement of problem: nowadays mineral trioxide aggregate (mta) is widely used for root end fillings, pulp capping, perforation repair and other endodontic treatments. investigations have shown similar physical and chemical properties for portland cement and root mta with those described for mta. purpose: the aim of this in vitro study was to evaluate the tissue reaction to implanted mta, portl...
A rapid, reliable and accurate method for the determination of hexavalent chromium in Portland cement is developed. The proposed method includes direct spectrophotometric determination of Cr (VI) in Portland cement with 1, 2, 5, 8 Tetrahydroxyanthraquinone, (Quinalizarin, QINZ) at pH 1.5. The European Directive (2003/53/EC) limits the use of cements so that it contains no more than 2 mg·Kg of w...
Properties of cement pastes with fine-ground ceramics used as an alternative binder replacing Portland cement up to 20% of its mass are investigated. At first, the particle size distribution of cement and fine-ground ceramics is measured using laser analyser. Then, the material properties are studied in the early hardening period up to 28 days. The hydration process of studied materials is moni...
This paper deals with the issues of air entraining and water/cement ratio in Portland Cement Concrete as related to its freeze thaw durability. Practices have been in place for nearly thirty years which demanded high early strengths in Portland Cement Concrete pavements. This paper looks at those practices, investigates the correlation between water/cement ratio and air entraining, and presents...
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