Radioactive waste generated during the reprocessing of fuel rods by the U.S. Department of Energy (DOE) is stored in underground tanks at Hanford, Savannah River and INEEL. The liquid fraction commonly referred to as sodium bearing waste (SBW), is a highly alkaline solution containing large amounts of sodium hydroxide, sodium nitrate and sodium nitrite. It has been shown that SBW can be mixed w...

Electromyography (EMG) of respiratory muscles is a reliable method of assessing the ventilatory muscle function, but still its use has not been fully utilized to determine the occupational and environmental hazards on respiratory muscles. Therefore, EMG of intercostal muscles was performed to determine the dose response effect of cement dust on respiratory muscles competence. Matched cross-sect...

In this paper, the effects of carbonation on pore structure of blended pozzolan cement pastes were investigated. Ordinary Portland cement OPC was partially replaced with ground palm oil fuel ash POA , ground rice husk ash RHA and classified fine fly ash FA . The strength, total porosity, specific surface area, and pore size distribution were tested. In general, incorporation of pozzolans increa...

Sustainability is important to the well-being of our planet, continued growth of a society, and human development. Concrete is one of the most widely used construction materials in the world. However, the production of portland cement, an essential constituent of concrete, leads to the release of significant amount of CO2, a greenhouse gas (GHG); production of one ton of portland cement produce...

background: cement production is associated with heavy metal emissions and environmental pollution by cement dust. the degree of contamination of drinking water sources by major and trace elements present in cement dust generated by united cement factory (unicem) is still uncertain. this study estimated the element content of ground and surface water samples (hand-dug wells, boreholes and strea...

The raw materials constituting the Portland cement are mainly lime, silica, alumina and iron oxide. During the manufacturing process, a glassy quasicrystalline clinker is formed which is ground, normally with addition of 1-3 wt% of CaSCU in the cement powder. This powder has four major constituents: 3 CaO"SiO2 (in cement chemists' notation C3S), 2 CaOSiO2 (C2S), 3 CaOAl2O3 (C3A) and 4 GaOAl2O3F...

Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass ...

Hydration products of Portland cement pastes, hydrated in water and in the presence of zinc ions were studied comparatively at different ages. Hydration products were studied by X ray diffractions (XRD) and infrared spectroscopy (IR). Although IR is not frequently used in cement chemistry, it evidenced a new phase Ca(Zn(OH) 3 ) 2 . 2H 2 O formed during cement hydration in the presence of zinc. ...

background and aims. mineral trioxide aggregate and calcium hydroxide are considered the gold standard pulp-capping materials. recently, portland cement has been introduced with properties similar to those of mineral trioxide aggregate. histopathological effects of direct pulp capping using mineral trioxide aggregate and portland cements on dog dental pulp tissue were evaluated in the present s...

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...