Fluidized Fly Ash Research Articles

Mechanical Properties of Concrete Mortar Based on Mixture of CRT Glass Cullet and Fluidized Fly Ash

The problem with the waste from electric and electronic equipment (WEEE), consisting of about 80% of television sets and computers containing a cathode ray tube (CRT) have just begun to deal with. Cathode ray tubes (CRTs) are the video display components of televisions and computer monitors (EPA, 1995). Arising problem related with recovery and recycling of CRT glass stimulates examinations aimed at making cullet-based ceramic materials of reinforced mechanical strength. Glasses as cone and neck contain principally different lead contents another dangerous elements instead panel glass has other heavy metals (Ba, Sr, etc.) that forbid their recycling in the glass industry for the production of containers, domestic glassware and glass fiber. As it is well known concrete is an excellent material for immobilization of these metals, what was the reason to undertake this research. The use of CRT (Cathode Ray tube) waste glasses in concrete has attracted a lot of interest worldwide due to the increased disposal costs and environmental concerns. Because of silica large quantities CRT glass in the theory is a pozzolanic in nature, thus it can be used as a sand replacement in light concrete. The research was performed with use of concrete mortars. As a reference concrete mortar a mix of cement, sand, expanded clay aggregate and water was used. The purpose of this work was to investigate the influence of additives e.g. CRT glass cullet as an aggregate, and fluidized fly ash on concrete properties. Based on obtained results both CRT glass cullet and fluidize fly ash improved compressive and flexural strength in respect of standard concrete mortar without these additives. The use of CRT glass as a sand replacement caused the increased of compressive strength of concrete mortar of about 16% and its flexural strength of about 14%.

Development of Microstructure of the Fly Ash Aerated Concrete in time

Calcium hydro-silicate components formed during the autoclaving process are highly complex formations which often blend together mutually and form a variety of intermediate products, from completely amorphous, to the good crystalline phases. For fly ash autoclaved aerated concrete, the situation is even more complicated by the fact that high temperature and fluidized fly ash, as basic silica ingredients, have high variability of the chemical and mineralogical composition. This paper presents the results of microstructure monitoring and physical and mechanical tests on samples of fly ash aerated concrete based on high temperature and fluidized fly ashes performed after 2 years of storage in laboratory conditions. The microstructure of aerated concrete is assessed on the basis of SEM images and mineralogical composition according to X-ray analysis. The changes in compressive strength, density and coefficient of thermal conductivity of the fly ash aerated concrete in time are evaluated.

Comparative Investigations of some Properties Related to Durability of Cement Concretes Containing Different Fly Ashes

The results of research of mechanical properties and selected other characteristics influencing durability of cement concretes containing cement substitutes were presented. Cement concretes performed with conventional fly ash, fluidised fly ash and their mixture were investigated. The obtained results were compared with findings registered for two types of concrete performed without cement replacements and with cement concrete containing silica fume. The results have shown that cement concrete with predetermined 28-day compressive strength of about 50 MPa and good workability may be obtained using different cement replacements. Generally, these cement concretes exhibited also favorable properties related to concrete durability, i.e. low permeability and sorptivity, and significant reduction of chloride migration coefficient. Favourable results were obtained for cement concrete containing mix of conventional and fluidised fly ashes: good workability, compressive strength after 28th day exceeding 50 MPa, low permeability of water, and low sorptivity, as well as low coefficient of chloride migration. These features were similar as for cement concrete containing silica fume.

Utilisation of Fluidised Fly Ash for Reduction of CO<sub>2</sub> Emissions at Portland Cement Production

The article deals with preparation of Portland cements from raw material powder with reduced carbonated component. This component is replaced with fluidised fly ash. With prepared model cements tests of basic technological properties were carried out.

Behavior of Class C Fly Ash during Firing at High Temperatures

Fluidized fly ash (class C according to ASTM) from thermal power plants Hodonin and Ledvice and stoneware clay B1 were used in the experimental work dealing with SO2 emissions during the firing at 1200°C. The aim of the work was to define the temperature at which sulphur dioxide begins to leak, and the leakage rate of SO2. It was found that temperature of decomposition of anhydrite depends on particle size. For milled fly ash is this temperature 150°C lower than for unmilled ashes. The addition of clay also decreases the temperature of decomposition. Sulphur dioxide begins to leak at 975 °C for samples with 40% addition of fly ash.

Influence of Fluidized Fly Ash on the Selected Physical-Mechanical Properties of the Autoclaved Aerated Concrete

Fluidized fly ash has different physical and chemical properties compared to fly ash emerging from classic combustion. It contains amorphous phases resulting from a dehydration of clay minerals as well as unreacted sorbent of CaCO3, free CaO and anhydrite (CaSO4). Work targets the possibilities of production of an autoclaved aerated concrete (AAC) from fluidized fly ash, and its influence on particular physical-mechanical properties of autoclaved aerated concrete.

Study on Fired Brick Using Large Amount of Low Calcium Fluidized Bed Boiler Fly Ash

Fired brick using hypocalcaemia fluidized bed boiler fly ash has been studied in this paper. It has been proposed that large amount of low calcium fluidized bed boiler ash fired brick has the best performance in the conditions of firing temperature of 1050 °C and holding time of eight hours. The influence of the amount of hypocalcaemia fluidized bed boiler fly ash to the performance of fired brick has been studied also. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Lightweight Artificial Aggregate Based on Fly Ash for New Rehabilitation Materials

During rehabilitation work are often strict requirements on the use of high quality lightweight materials, including aggregate. Due the constantly increasing social pressure on the optimal use of secondary raw materials is therefore most appropriate to exploit the potential of fly ash as mineral residue from the combustion of ground coal in power plants. Especially filter fly ash has proven to be an adequate substitute for traditional materials in the past. This article deals with the evaluation of physical and mechanical properties of cold-consolidated pellets based on conventional and fluidized fly ash with various cement addition.

The effect of fluidized fly ash on the properties of dry pressed ceramic tiles based on fly ash–clay body

Stoneware clay (40 wt.%), classical high-temperature fly ash and fluidized fly ash from two different power plants used in various mixing ratios were the base raw materials for the mixture for production of dry pressed ceramic tiles of the BIII group according to EN 14411. The influence of an increasing addition of fluidized fly ash in the raw material mixture and the granulometry of fly ashes (milling) on the properties of the fired fly ash–clay body have been studied after firing at 1080 °C (water absorption, bulk density, apparent density, apparent porosity and bending strength). Fluidized fly ash reduces firing shrinkage and increases the porosity of the body, which is more remarkable when non-milled fluidized fly ash is used. It is possible to use max. 20 wt.% of fluidized fly ash in the fly ash–clay mixture so that the properties of the fired body meet the requirements of the BIII Group for a body of dry pressed ceramic tiles. The fluidized fly ash dramatically increases the content of sulphur dioxide in flue gases during the firing.

96/03807 Non-dusty treatment of fluidized bed combustion coal fly ash and its application to soil stabilization

96/03807 Non-dusty treatment of fluidized bed combustion coal fly ash and its application to soil stabilization

95/03569 Production of minimal natural resource concretes utilizing fluidized bed combustion by-products and conventional power plant fly ash

95/03569 Production of minimal natural resource concretes utilizing fluidized bed combustion by-products and conventional power plant fly ash