Quartz (α-quartz), is the most common crystalline silica polymorph in nature and is the only polymorph found in significant concentrations in coal and coal ash. Since exposure to quartz is liable to cause lung diseases, it is very important to know its concentrations in coal ash and to evaluate its effects on the workers. Inhalation is the most effective route of entry for airborne particles of...

This project consisted of performance testing and evaluation of concrete containing high-carbon fly ash and carbon fibers. One of the primary aims of this project was to further determine the effect of using high-carbon fly ash and carbon fibers on the electrical properties of concrete. This is a part of the continuing work performed initially by the UWM Center for By-Products Utilization (UWM-...

An estimated 229,000 m(3) of coal fly ash remains in the river system after dredging to clean-up the 2008 Tennessee Valley Authority (TVA) spill in Kingston, Tennessee. The ash is heterogeneous with clear, orange and black spheres and non-spherical amorphous particles. Combustion produces iron oxides that allow low field magnetic susceptibility (χ(LF)) and percent frequency dependent susceptibi...

An investigation was conducted to determine the influence of recycled scrap tire rubber on the engineering properties of controlled low strength material (CLSM). With control over the ultimate compressive strength of CLSMs being key for applications such as backfilling utility trenches where re-excavation is often necessary, incorporation of scrap tire rubber into the CLSM mixture is a viable w...

The present study was conducted for the removal of color of pulp and paper mill effluent using coal fly ash as an adsorbent. The effect of adsorbent dose and pH on color removal has been determined. 100 % color removal was achieved when adsorbent dose was 2.4 gm or more and at pH 6.8 and above. Jr. of Industrial Pollution Control 24 (1)(2008) pp 1-8 © Enviromedia Printed in India. All rights re...

Considering the increasing demand for developing alternative construction materials, due to the growing environmental concerns, this paper discusses the feasibility of alkali activated geo-polymer concrete, as a future construction material. The main objective of this study involves observation of structural behaviours of the fresh fly ash-based geo-polymer concrete, understanding the basic mix...

Human impacts on Earth are now so great that they have led to the concept of a new geological epoch defined by this global human influence: the Anthropocene. While not universally accepted, the term is increasingly popular and widely used. However, even among proponents, there is considerable debate regarding when the epoch may have started, from coeval with the Holocene, through the Industrial...

Rigid-wall column tests are performed at a hydraulic gradient of 100 on 21 compacted mixture contai.ning a Class F fly ash, sand, benton.ite, and cement. Results indicate that combina1ions of the admixtures can lower the permeability of the fly ash by up to an order of magnitude. There appears to be an optimum percentage of fly ash that minimizes the permeability of fly ashsand mixtures. Specim...

Employees of coal-fired power stations and people living nearby as well as those involved in the shipment and processing of coal fly ash can be exposed to coal fly ash (pulverised fuel ash or “PFA”). An extensive research program was carried out in order to map such exposure and its effects. Particle size distribution, chemical composition, quartz, radioactivity, emission factors and fugitive d...

In a previous paper, Brouwers and Van Eijk [1] presented a theoretical study on the dissolution (reaction) of pulverised powder coal fly ash. This fly ash was modelled as hollow spheres, and a shrinking core model was derived for these hollow spheres that contain two regions (an outer hull and an inner region). The obtained analytical equations were applied to the dissolution experiments by Pie...