Calcium leaching induced aging in concrete creates a new material with degraded macroscopic mechanical properties. Although the degradation of strength has been elaborately studied in the last decade, the degradation of elasticity has not been investigated in the same depth. This thesis presents a combined experimental-theoretical investigation of the loss of elastic modulus due to calcium leac...

Bioleaching and biogenesis are the main outputs from a large group of environmental processes participating in the natural material cycle, used in raw materials processing. Bio-oxidation reactions are the main basis for bioleaching procedures, often participating in parallel leaching processes. During the leaching processes of polycomponent sulphide substrates, the factor of process selection a...

In recent years, a lot of work has been carried out in evaluating environmental impact from a wide variety of materials in a wide range of different applications. The continously recurring inability to compare results between different jurisdictions and between disciplines can be resolved by focusing on a limited number of key test methods. This does require the recognition that many existing t...

Accumulation of soluble salts in arid areas which are similar to most regions of Iran is inevitable in soil surface and profile because of low precipitation and high evaporation. High concentration of soluble salts in soil profile caused severe problems for root water uptake thus plant growth stopped. Reducing soil salinity to optimized content by leaching and avoiding soil pounding must be con...

This study involved preliminary laboratory test work to identify the relative leaching response to cyanidation and thiourea leaching of an oxidized low grade gold ore based on characterization studies. Huge reserves of gold deposits have been reported from different parts of Iran, especially at Neishaboor area with gold grade of approx 4 ppm. For the mineralogical composition, the nature of the...

Soils from many industrial sites in southeastern USA are contaminated with As because of the application of herbicide containing As2O3. Among those contaminated sites, two industrial sites, FW and BH, which are currently active and of most serious environmental concerns, were selected to characterize the occurrence of As in the contaminated soils and to evaluate its environmental leachability. ...

Assessing potential long-term forest productivity requires identification of the processes regulating chemical changes in forest soils. We resampled the litter layer and upper two mineral soil horizons, A and AB/BA, in two aggrading southern Appalachian watersheds 20 yr after an earlier sampling. Soils from a mixed-hardwood watershed exhibited a small but significant decrease in soil pH. Extrac...