abstract  background: the essential constituents of cements like lime, silica and alumina are derived from earth’s crust in which radioactive elements like uranium, thorium etc are also present in varying amounts almost everywhere. these two elements are considered as the parent elements of uranium and thorium radioactive decay series in which radon and thoron are produced respectively as decay...

The construction of coastal ports requires the use materials that meet demands marine environment, to prevent underwater concrete structures from cracking and spalling easily; basalt fiber is used delay expansion formation cracks. This research studies behavior for prefabricated piles with Portland Cement Type I fibers added in 0.1%, 0.3% 0.6%; results indicate suitable concrete, slump decrease...

Calcium Silicate Hydrate (C-S-H) is the main hydration product of Portland cement, it has an important impact on the properties of cement and causes a wide range of study. In recent years, superplasticizer, of which the main component is organic macromolecules, has become an important component in preparation for high performance concrete. Molecular dynamics simulation of cement hydration produ...

A simple flow injection with flame photometric detection has been developed for determination of sodium, potassium, and total alkalies in portland cement, fly ash, admixtures, and water of concrete. A liquid sample or a digest of solid sample was injected into a water carrier stream which flowed to a flame photometer. A change in emission intensity at a selected wavelength was recorded as a pea...

Expansive cement is a unique type of that, when mixed with water, produces paste which expands in volume significantly more than standard Portland cement. This expansion nullifies the deficit shrinkage that arises during concrete hardening. paper presents outcomes two phases experimentation. Phase I provides summary performance expansive mixes prepared various proportions cement, partially supp...

ABSTRACT  Background: The essential constituents of cements like lime, silica and alumina are derived from earth’s crust in which radioactive elements like uranium, thorium etc are also present in varying amounts almost everywhere. These two elements are considered as the parent elements of uranium and thorium radioactive decay series in which radon and thoron are produced respectively as decay...

OBJECTIVE To evaluate the biocompatibility and the setting time of Portland cement clinker with or without 2% or 5% calcium sulfate and MTA-CPM. MATERIAL AND METHODS Twenty-four mice (Rattus norvegicus) received subcutaneously polyethylene tubes filled with Portland cement clinker with or without 2% or 5% calcium sulfate and MTA. After 15, 30 and 60 days of implantation, the animals were kill...

dust can be produced by almost all production processes in portland cement factory. dust exposure potentially can affect respiratory function. but evidence for respiratory effect of cement dust exposure has not been conclusive. in this study we assessed effect of cement dust exposure on respiratory function in a cement production factory. a respiratory symptoms questionnaire was completed and p...

the present study aimed at assessing cement dust exposure and its relationship to lung function at a portland cement factory in ilam, iran. lung function tests were carried out on 112 workers at the cement factory in 2008-09. simultaneously 85 non exposed workers were used as control. lung function tests were performed for all subjects. additionally, total dust level was determined by the gravi...