scholarly journals Soil concrete based on waste of heat power engineering and siftings of rock grinding

2019 ◽  
Vol 140 ◽  
pp. 05015
Author(s):  
Natalia Konovalova ◽  
Elena Rush ◽  
Dmitry Bespolitov ◽  
Pavel Pankov
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Phase Analysis ◽  
Building Materials ◽  
Specific Activity ◽  
Natural Radionuclides ◽  
Mining Industry ◽  
Emission Spectrometry ◽  
Heat Power ◽  
X Ray

The possibility of recycling large-tonnage waste of heat power engineer-ing and mining industry in road construction is shown. Compositions of road-building materials were researched, containing siftings of rock grinding, fly ash, Portland cement, modified with a stabilizing additive of polymeric nature. X-ray phase analysis showed availability of quartz in fly ash, calcite, feldspars, goethite and X-ray amorphous phase, what is consistent with the data of infrared spectroscopy. By atomic emission spectrometry with inductively coupled plasma it was revealed that fly ash is latent-active and can be disposed in compositions in the presence of a stabilizing additive. The X-ray phase analysis of grinding siftings showed that it contains quartz, feldspars, chlorite, calcite and dolomite. The specific activity of natural radionuclides (226Ra, 232Th, 40К) of fly ash and grinding siftings was 248 and 110 Bq/kg, which allows using such waste in construction without restrictions. It was revealed that the initial mineral raw materials belong to multiphase polymineral systems; therefore, when modifying them with stabilizing additives, binding of finely divided particles should be taken into account. It was revealed that the optimal content of Portland cement and fly ash in samples is 8 and 10 wt.%. It was found that an increase in the mass fraction of fly ash in the composition of soil-concrete up to 30 wt.% leads to softening of the samples and a decrease in their strength characteristics.

scholarly journals INFLUENCE OF THE SCOPE ADDITION ON THE STRUCTURE FORMATION OF THE CEMENT STONE BY THE METHOD OF QUANTITATIVE X-RAY PHASE ANALYSIS

2019 ◽  
Vol 16 (4) ◽  
pp. 504-518
Author(s):  
I. L. Chulkova ◽  
I. A. Selivanov ◽  
V. D. Galdina
Keyword(s):  
Portland Cement ◽  
Structure Formation ◽  
Phase Analysis ◽  
Mineral Composition ◽  
Large Scale ◽  
Building Materials ◽  
Cement Matrix ◽  
Cement Stone ◽  
X Ray ◽  
Mineral Compositions

Introduction. The processes of structure formation of cement compositions and the development of effective technologies of building materials is an urgent task for building material science. The use of large-scale man-made product of pulp and paper enterprises – osprey as a fibrous filler in organic and mineral compositions is the successful decision of the problem. The paper analyzes the ways of using osprey in the building materials’ production. The aim of the research is to study the osprey influence on the processes of structure formation of cement stone by quantitative x-ray phase analysis.Materials and methods. The organic and mineral compositions were obtained on the basis of portland cement and osprey. The authors studied the compositions’ phase of osprey, portland cement and the processes of cement stone structure formation in organ and mineral compositions by quantitative x-ray phase analysis.Results. The authors determined the compositions’ phase of mineral impurities of osprey, cellulose, cement, cement stone, organic and mineral compositions and two compositions containing 25 and 75% by weight.Discussion and conclusions. The osprey application as a filler in the organic and mineral composition causes inhibition of processes of cement hydration. The presence of osprey in the hardening organic and mineral composition leads to a change in the composition and structure of the cement stone in comparison with the phase composition of the cement stone without additives. The result of these changes is a significant increase in the amount of calcite, waterite and a significant decrease in the amount of portland. The authors establish that the effective joint work of the reinforcing component of the osprey with the cement matrix is possible with a limited amount of osprey in organic and mineral compositions.

Method of Non-Destructive Measurement of Natural Radionuclides Concentration in Building Materials

ANRI ◽  
2021 ◽  
Vol 0 (1) ◽  
pp. 31-44
Author(s):  
Aleksey Vasil'ev ◽  
Aleksey Ekidin ◽  
Mariya Pyshkina ◽  
Georgiy Malinovskiy ◽  
Aleksandra Onischenko ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Flux Density ◽  
Building Materials ◽  
Specific Activity ◽  
Natural Radionuclides ◽  
Gamma Spectrometer ◽  
Average Activity ◽  
Destructive Measurement ◽  
Non Destructive ◽  
Calculated Flux

A method for non-destructive monitoring of the content of natural radionuclides in building materials has been developed. Spectrum measurements of gamma radiation are carried out with a pre-calibrated field gamma spectrometer. The calculation of the average specific activity of natural radionuclides in building materials is carried out by comparing the calculated flux density of unscattered gamma quanta normalized to the specific activity, and the experimentally measured count rates in the photopeak. calculated for the geometry of the room under study and the location of the detector. Application of the developed method makes it possible to estimate the average activity of natural radionuclides in building materials without destruction.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

Development of Sustainable Alternative Building Materials from Quarry Dust

2018 ◽  
Vol 761 ◽  
pp. 181-188
Author(s):  
Ehud Cohen ◽  
Gabriela Bar Nes ◽  
Alva Peled
Keyword(s):  
Fly Ash ◽  
Building Material ◽  
Building Materials ◽  
Waste Product ◽  
Mining Industry ◽  
Chemical Properties ◽  
High Volume ◽  
Waste Products ◽  
Quarry Dust ◽  
And Chemical Properties

The main goal of our work is to develop an alternative building material based on “zero waste” objective, thus creating commercially valuable products from materials that are otherwise high-volume waste products. Fine dolomitic quarry dust is a waste product manufactured in several millions of cubic tons each year in the mining industry of Israel. Our study examines a sustainable and useful solution to use this quarry dust (QD) as a part of fly ash based geopolymeric systems. Mechanical, thermal and chemical properties were examined and analyzed.

Stability of Cs-Ionsiv in Portland cement blends for radioactive waste disposal

2010 ◽  
Vol 1265 ◽  
Author(s):  
Neil Christian Hyatt ◽  
Andreas Jenni ◽  
Martin Christopher Stennett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fly Ash ◽  
Radioactive Waste ◽  
Portland Cement ◽  
Radioactive Waste Disposal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Leaching Experiments ◽  
Scanning Electron

AbstractThe suitability of Portland cement blends for encapsulation of Cs-Ionsiv in a monolithic wasteform was investigated. No evidence of reaction or dissolution of the Cs-Ionsiv in the cementitious environment was found by scanning electron microscopy and X-ray diffraction. However, a small fraction (≤1.6 wt%) of the Cs inventory was released from the encapsulated Ionsiv during leaching experiments carried out on hydrated samples. Cs release was enhanced by exchange of K and Na present in the cementitious pore water. Cement systems lower in K and Na, such as slag based blends, showed lower Cs release than the fly ash based analogues.

scholarly journals Parametric Strategy for Composite Cement Concrete Blended with Fly Ash & Glass Fiber

2020 ◽  
pp. 162-176
Author(s):  
Madhurima Das ◽  
Siba Prasad Mishra
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Glass Fiber ◽  
Building Materials ◽  
Cement Concrete ◽  
Strength Performance ◽  
X Ray ◽  
Natural Building ◽  
The Impact ◽  
Scanning Electron

Coping with population growth, houses are built to meet the hike. The prerequisites for concrete and steel reinforcements have surged up globally since last 3 to 4decades. Shortage of natural building materials, increased wastes from coal based industries to augment carbon foot print has worried the engineers to reuse their wastes (such as fibres, powders, granules, etc.) as building materials ingredient. Glass fibre has improved flexural capabilities with fly ash dosages in cement concrete and alternately helps in restricting environmental degradation. Present research aims at investigating the impact of glass fiber (at 1%, 2% and 3% addition) and fly ash (dosages of 10% and 20% over the existing fly ash in PPC). The ingredients and microstructure of composites are found by either X-ray fluorescent spectroscopy or scanning electron microscope. Experimental evaluation results of the blended composite concrete parameters of RCC are experimentally evaluated and compared have shown that concrete with 10% cement substitution with fly ash and 3% fibre showed optimum compressive strength performance than the concrete without fibre and fly ash and also chemically resistant against commonly used M-20 grade of Concrete.

scholarly journals Kinetics Study of Al Extraction from Desilicated Coal Fly Ash by NaOH at Atmospheric Pressure

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7700
Author(s):  
Andrei Shoppert ◽  
Irina Loginova ◽  
Dmitry Valeev
Keyword(s):  
Fly Ash ◽  
Atmospheric Pressure ◽  
Inductively Coupled Plasma ◽  
Coal Fly Ash ◽  
Acid Leaching ◽  
Emission Spectrometry ◽  
Pressure Leaching ◽  
Water Leaching ◽  
X Ray ◽  
Promising Source

The most promising source of alumina in the 21st century is the coal fly ash (CFA) waste of coal-fired thermal plants. The methods of alumina extraction from CFA are often based on the pressure alkaline or acid leaching or preliminary roasting with different additives followed by water leaching. The efficiency of the alumina extraction from CFA under atmospheric pressure leaching is low due to the high content of acid-insoluble alumina phase mullite (3Al2O3·2SiO2). This research for the first time shows the possibility of mullite leaching under atmospheric pressure after preliminary desilication using high liquid to solid ratios (L:S ratio) and Na2O concentration. The analysis of the desilicated CFA (DCFA) chemical and phase composition before and after leaching has been carried out by inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The morphology and elemental composition of solid product particles has been carried out by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). An automated neural network and a shrinking core model (SCM) were used to evaluate experimental data. The Al extraction efficiency from DCFA has been more than 84% at T = 120 °C, leaching time 60 min, the L/S ratio > 20, and concentration of Na2O-400 g L−1. The kinetics analysis by SCM has shown that the surface chemical reaction controls the leaching process rate at T < 110 °C, and, at T > 110 °C after 15 min of leaching, the process is limited by diffusion through the product layer, which can be represented by titanium compounds. According to the SEM-EDX analysis of the solid residue, the magnetite spheres and mullite acicular particles were the main phases that remained after NaOH leaching. The spheric agglomerates of mullite particles with non-porous surface have also been found.

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