نتایج جستجو برای: portland cement

تعداد نتایج: 30488  

Journal: :European archives of paediatric dentistry : official journal of the European Academy of Paediatric Dentistry 2009
R Steffen H van Waes

AIM This was to carry out a review of the literature concerning mineral trioxide aggregate (MTA) and Portland cement with regards to clinical, biological and mechanical findings and a possible substitution of MTA through Portland cement for endodontic use. STUDY DESIGN Electronic literature search of scientific papers from January 1993 to January 2009 was carried out on the MEDLINE and Scopus...

مهدوی آکردی, مهدی, رقیمی, مصطفی , شمعانیان, غلامحسین , قلی پور, محسن ,

Portland cement could be produced by heating the raw materials (clay, limestone) about 1500°C which clinker will be formed. Geochemical and mineralogical studies of clinker, Portland cement, cement kiln dust and cement mill dust have been carried out by optical microscopy, X-ray diffraction and X-ray florescence. In phase system diagram (CaO-Al2O3-SiO2), chemical components of clinker cement oc...

2016
Shahriar Shahi Negin Ghasemi Saeed Rahimi Hamidreza Yavari Mohammad Samiei Farnaz Jafari

BACKGROUND The Portland cement is hydrophilic cement; as a result, the powder-to-liquid ratio affects the properties of the final mix. In addition, the mixing technique affects hydration. The aim of this study was to evaluate the effect of different mixing techniques (conventional, amalgamator and ultrasonic) on some selective physical properties of Portland cement. MATERIAL AND METHODS The p...

Journal: :Journal of oral science 2009
Shahriar Shahi Saeed Rahimi Maryam Hasan Vahab Shiezadeh Majid Abdolrahimi

The purpose of this study was to compare the sealing ability of gray mineral trioxide aggregate (GMTA), white MTA (WMTA), and both white and gray Portland cement as furcation perforation repair materials. A total of 120 human mandibular first molars were used. After root canal obturation and preparation of furcal perforations the specimens were randomly divided into four groups of 25 teeth each...

2005
Carlos Eduardo M. Gomes Osny P. Ferreira

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...

2010
Lance Brothers Benjamin Iverson Daniel Bour

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...

2016
Kejin Wang Zhiyou Wen

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...

2013
El-Sayed Moussa Negim Jamal Khatib Mohammed Muhanna Mohammed

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...

2004
Glen H. Kirby Jennifer A. Lewis

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...

Journal: :journal of dentistry, tehran university of medical sciences 0
h. razmi d. sharifi p. mottahari mr. khosravi

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 ...

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