research on the heavy concrete technology expanded rapidly in the last decades. this kind of the concrete can be used for different purposes such as the protective shields of the medical centers and nuclear power plants. ilmenite, limonite, hematite, magnetite and barite are the common mineral aggregates which are used in the heavy concrete construction technology. in this research the mechanic...

background: high density concrete is extensively used for efficient radiation attenuation in radiotherapy rooms and nuclear reactors. over the past eight years, some efficient galena-based concrete samples for shielding x or gamma rays was produced. the goal of this study was to produce a novel high density concrete against neutron and photon radiations using tourmaline and galena. materials an...

Introduction: The role of radiotherapy as a part of cancer management increases every year around the world. Thus, Radiation protection in the design of radiotherapy rooms are of great importance.   Materials and Methods: In present study using Monte Carlo method, MCNPX code, fourteen types of developed high density concretes with densities ranging from 2.45 ...

background: biological shielding of nuclear reactors has always been a great concern and decreasing the complexity and expense of these installations is of great interest. in this study, we used datolite and galena (daga) minerals for production of a high performance heavy concrete. materials and methods: datolite and galena minerals which can be found in many parts of iran were used in the con...

A failure mode and effect analysis (FMEA) was applied to improve the design of concrete ties in ballasted track for North American heavy haul applications. A literature review was conducted on concrete tie failure modes, failure effects, and failure causes. A survey of railroads and transit authorities in North America provided a ranking of the most critical concrete tie failure modes. The most...

The main objective of this study is to evaluate the workability of fresh portland cement concrete while it is still in the mixing truck by determining fundamental rheological parameters (plastic viscosity and yield stress). Nine concrete mixtures with different values of yield stress and plastic viscosity were tested in a concrete truck. The measurements made with the truck were based on the ty...

Background: Biological shielding of nuclear reactors has always been a great concern and decreasing the complexity and expense of these installations is of great interest. In this study, we used datolite and galena (DaGa) minerals for production of a high performance heavy concrete. Materials and Methods: Datolite and galena minerals which can be found in many parts of Iran were used i...

After the demolition of concrete structures, it is expected to recycle the whole of the demolished concrete. As of now, however, it is difficult to recycle the fine powders generated in the processes of demolition of concrete and manufacture of recycled aggregate because these powders may contain heavy metals exceeding the soil environmental standard, and such powders are disposed finally. It i...

Solidification of industrial sludge in concrete matrices has been examined. The concrete mixes in which galvanic sewage sludge was immobilised were prepared with the use of two binder types: Portland-fly ash cement CEM II/B-V, and a binder composed of Portland cement (60%) and fly ash obtained from fluidized bed combustion of fuels (40%). Leaching of heavy metals (Cr, Cd, Zn, Ni, Cu, Pb, V) was...