/pdf/a-comprehensive-review-on-the-applications-of-coal-fly-ash-mt8gcj5phv.pdf

A comprehensive review on the applications of coal fly ash

Sorption of dyes from aqueous solutions onto fly ash.

The current widespread use of calcium silicate or aluminate hydrate binder systems in the construction industry finds its roots in the Antique world where mixtures of calcined lime and finely ground reactive (alumino-)silicate materials were pioneered and developed as competent inorganic binders. Architectural remains of the Minoan civilization (2000-1500 BC) on Crete have shown evidence of the combined use of slaked lime and additions of finely ground potsherds to produce stronger and more durable lime mortars suitable for water-proof renderings in baths, cisterns and aqueducts (Spence and Cook 1983). It is not clear when and where mortar technology evolved to incorporate volcanic pumice and ashes as a functional supplement. A plausible site would be the Akrotiri settlement at Santorin (Greece), where archeological indications of strong ties with the Minoan culture were found and large quantities of suitable highly siliceous volcanic ash were present. This so-called Santorin earth has been used as a pozzolan in the Eastern Mediterranean until recently (Kitsopoulos and Dunham 1996). Evidence of the deliberate use of this and other volcanic materials by the ancient Greeks dates back to at least 500-400 BC, as uncovered at the ancient city of Kamiros, Rhodes (Efstathiadis 1978; Idorn 1997). In the subsequent centuries the technological knowledge was spread to the mainland (Papayianni and Stefanidou 2007) and was eventually adopted and improved by the Romans (Mehta 1987). The Roman alternatives for Santorin earth were volcanic pumices or tuff found in neighboring territories, the most famous ones found in Pozzuoli (Naples), hence the name pozzolan, and in Segni (Latium). Preference was given to natural pozzolan sources, but crushed ceramic waste was frequently used when natural deposits were not locally available. The exceptional lifetime and preservation condition of some of the most famous Roman buildings such as the Pantheon or the Pont du …

Supplementary Cementitious Materials

A review of the alumina recovery from coal fly ash, with a focus in China

State-of-the-art applications of fly ash from coal and biomass: A focus on zeolite synthesis processes and issues

Mineralogy and microstructure of sintered lignite coal fly ash

Considering the fact that urbanization is one of the most serious threats to geodiversity, it is important that this issue is taken into account in spatial development plans and georesource management strategies in urban areas. This paper presents the application of a geodiversity evaluation method by using the geodiversity index, based on the quantity of abiotic elements and relief roughness within a spatial unit. Geodiversity assessment, usually used for remote, protected and sparsely populated natural areas, is now carried out in an urban environment – the city of Belgrade, capital of Serbia, with a population of about 1.7 million inhabitants and very strong urbanization in the last few decades. The area of 3227 km2 is processed with the spatial resolution of 1 x 1 km. The acquired results from the geodiversity index are analyzed in the context of sustainable use of georesources and the threats to which geodiversity is exposed due to the territorial expansion of the city. The mapping of specific categories of geodiversity on the basis of quantitative assessment with the use of Geographic Information Systems can help decision makers and managers to take further steps that would reduce threats and protect the natural value of Belgrade.

http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/gc.2016.27/pdf

Application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the Belgrade city area, Serbia

The karstic spring Perucac as the main drainage area of the Tara Mt. in western Serbia was studied in order to assess its discharge regime, water reserves, and to delineate its catchment area. The spring is located in the northeastern, inner zone of the classic Dinaric karst, which is characterized by a dominant extension of highly karstified Triassic limestones, a poorly developed hydrographic network with many ponors, and dense forests. Tara Mt. is one of five national parks in Serbia. The goal of the project was to identify a high-priority protection zone within the preserved natural area which is also well known and actively used for tourism and recreation purposes. Based on data on the discharge regime of the Perucac Spring, and by applying the multiple non-linear correlation method, the size of the direct catchment area was assumed to be 79.3 km2, which was 5–18 % larger than that estimated by previous surveys. Proposal to extend preserved natural area and to include sanitary protection zone of the Perucac spring as well as to establish a common monitoring system for biodiversity and water has been made. In this way, not only native plants and animals but also their habitats would be better protected from potential pollution.

An example of karst catchment delineation for prioritizing the protection of an intact natural area

The establishment of detailed monitoring of quantitative and qualitative parameters of groundwater in the zone of possible interactions between a water-conveyance tunnel and the geologic/hydrogeologic environment is of the utmost importance for assessing the risk of adverse effects and of tunnel performance. The water-conveyance tunnel of the Pirot Hydropower Plant (HPP Pirot) is a good example of applying detailed monitoring in complex geologic/hydrogeologic conditions resulting from the presence of an underground structure. The research scheduling was conditional upon the operating regime of the tunnel (whether it is in or of operation—online or offline). While the tunnel was operating (online), monitoring was conducted at observation wells along the tunnel (approx 15 m distant), a control gate (water losses), springs, and a stream in the vicinity of the tunnel. Areas of the potential hydraulic instability were indicated by synchronous measurements of water level and temperature changes in the observation wells and at the control gate. While the tunnel was offline (empty tunnel) it was possible to access the tunnel, and in situ monitoring proved to be of great importance. Observations of quantitative parameters pointed out hydraulically critical tunnel zones, whilst the qualitative characteristics of groundwater revealed their potential aggressiveness to the concrete lining of the tunnel. The applied methodology shows that a detailed observation program should be an important task of sustainable tunnel management.

https://www.mdpi.com/2073-4441/11/3/603/pdf

The Importance of Detailed Groundwater Monitoring for Underground Structure in Karst (Case Study: HPP Pirot, Southeastern Serbia)

This hydrogeochemical research was conducted to improve the understanding of (1) groundwater flow and its hydrochemical evolution in a complex karst-fissured aquifer system, and (2) the interaction between groundwater and water transported via hydraulic tunnel of the hydropower plant (Pirot, Serbia). The tunnel traverses the main fault zones between two regionally important tectonic units, Getic and Danubian, allowing deep groundwater circulation and higher infiltration of groundwater into the tunnels. Water samples were collected at the surface and within the tunnels in four different sampling campaigns, depending on the tunnel operational regime in 2016, and measurements of physicochemical parameters (pH, ORP, EC, T) and groundwater sampling for chemical analysis (Ca, Mg, Na, K, Sr, Li, HCO3, SO4, Cl, NO3, H2S) were conducted. This was a unique opportunity to investigate hydrochemical processes based on groundwater leakage along the tunnel profile line. The main problem is compounded by the fact that it is a hydraulic tunnel that transports water under pressure, thereby interacting with the hydrogeological environment. Changes in the tunnel operational mode cause hydraulic changes in the hydrogeological environment, which is a key part of this research. The presence of different hydrochemical facies appearing in the tunnel (from Na–Cl through Na-HCO3 to Ca(Mg)–HCO3 water types) pointed to the complexity of the hydrogeological system in the shallow, and deep groundwater flow systems developed in karst and fissured aquifer. Heterogeneity of bedrock had an important influence on the hydrochemical conditions accompanied by processes revealed through hydrochemical and multivariate statistical analysis: hierarchical cluster analysis (HCA) and principal component analysis (PCA). The main processes are defined as (1) dissolution processes in hypogenic conditions of the karst hydrogeological system, associated with high mineralization of groundwater, (2) cation exchange process, (3) the dissolution of different types of carbonate bedrock. A combined approach of multivariate statistical analysis and standard hydrochemical methods enabled the separation of groundwater with the highest compositional changes as points of the strongest artificial influence in the narrow tunnel zone.

Marina Čokorilo Ilić

Papers

Mineralogy and microstructure of sintered lignite coal fly ash

Application of the geodiversity index for the assessment of geodiversity in urban areas: an example of the Belgrade city area, Serbia

An example of karst catchment delineation for prioritizing the protection of an intact natural area

The Importance of Detailed Groundwater Monitoring for Underground Structure in Karst (Case Study: HPP Pirot, Southeastern Serbia)

Hydrochemical impact of the hydraulic tunnel on groundwater in the complex aquifer system in Pirot, Serbia