Авторы выражают искрению благодарность директору ООО НКП “Геоинтек” канд. геол.-мин. наук С.Е. Поповченко за предоставленное оборудование, помощь в проведении экспериментов и консультации.

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Recycling of Prydniprovska thermal power plant fly ash

The paper provides a comparative assessment of using four types of fuel ashes from different types of coal combustion as additives to replace part of the cement in producing a composite binder. The authors assessed the effectiveness of the additives by cement dough properties (water-binder ratio, normal density, initial setting) and the strength of the binder at 1, 3, 7 and 28 days of hardening. The ashes are ranked according to their efficiency in the structure of composite binder in the following sequence: acid ash from Reftinskaya power plant → acid ash from Novotroitskaya power plant → basic ash from Nazarovskaya power plant → acid ash from Troitskaya power plant. The research revealed that the most effective mineral additives were basic ash from the Nazarovskaya power plant and acid ash from the Troitskaya power plant. Their use reduced the amount of cement by 15% and 25% respectively, while reducing the strength by no more than 3%.

Properties of a Composite Cement Binder Using Fuel Ashes

Reducing the consumption of the most widespread and expensive in construction inorganic binder of hydration hardening type - Portland cement - is one of the most important tasks for the construction industry. With the current trend of resource- and energy-saving, as well as a decrease in environmental pressure, it is of great interest to use wastes from fuel and energy enterprises in the form of various types of ash (acidic, basic), which are finely dispersed raw materials of mainly aluminosilicate composition that have accumulated in large quantities on our country territories. The paper analyzes the effect of mineral additives in the form of fuel ashes, the use of which provides replacement of part of Portland cement (15-30 % of the total mass of Portland cement, in increments of 5 %), on the kinetics of hardening of the binder. Based on the results of the strength tests of binder samples with additives, calculation of predicted strength was carried out according to the methodology by Sh.M. Rakhimbayev based on transfer theory. As a result, the analysis of the kinetics of the Portland cement hardening was carried out both at early and late hardening periods; efficiency and optimal concentration of fuel ashes depending on type have been established.

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Forecasting strength of portland cement in the presence of fuel ashes

: This paper considers and solves the issues of taking into account the inverse eﬀect of process characteristics (liquid concentration and sediment contamination) on the environment characteristics (porosity, ﬁltration, diﬀusion, mass transfer, etc.) on the example of liquid puriﬁcation in magnetic and sorption ﬁlters. An algorithm for numerical- asymptotic approximation of the corresponding model problem solution is obtained, which is described by a system of non-linear singularly perturbed diﬀerential equations of the type “convection-diﬀusion-mass transfer”. Appropriate ratios (formulas) are eﬀective for optimizing the water treatment process and increasing the treatment system productivity as a whole (allow to determine the ﬁlter protective time, the ﬁlter size, etc.) in cases of convective predominance and sorption compo-nents of the corresponding process over diﬀusion and desorption which occurs in the vast majority of ﬁlter systems. On this basis, a corresponding com-puter experiment was conducted, the results of which show the proposed model advantages in comparison with classical.

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Mathematical modeling of the water purification process taking into account the inverse effect of the process characteristics on the characteristics of the environment

Цель. В статье необходимо провести установление закономерностей влияния состава мелкозернистых бетонов, получаемых на основе доменных гранулированных шлаков, и продолжительности обработки бетонной смеси в смесителе-активаторе на основные свойства материала. Методика. Для достижения поставленной цели в работе использован полнофакторный эксперимент типа 2 2 . В качестве переменных были приняты: соотношение между цементом и доменным гранулированным шлаком ( X 1 ) и продолжительность обработки бетонной смеси в смесителе-активаторе ( X 2 ). Выходными факторами, т.е. контролируемыми свойствами, были: ранняя прочность в 7-суточном возрасте ( Y 1 = f 7 сут ), стандартная прочность в 28-суточном возрасте ( Y 2 = f 28 сут ) и средняя плотность бетона ( Y 3 = ρ ), твердеющего в нормальных условиях. Результаты. Анализ полученных моделей регрессии свидетельствует о том, что с уменьшением содержания заполнителя в составе бетона и повышением продолжительности обработки смеси в смесителе-активаторе прочность в разные сроки твердения и плотность бетона возрастают. При этом большее влияние на свойства бетона имеет изменение состава смеси. Так, при одинаковом времени обработки смеси прочность бетона в возрасте 28 суток понижается примерно на 30 % между составом 1:3 и 1:4 ; на 22 % − между составом 1:4 и 1:5 ; на 13 % − между составом 1:5 и 1:6. Та же закономерность прослеживается и для ранней прочности бетона. Плотность бетона мало изменяется, ее кривая расположена практически в одной плоскости. Так, при равной продолжительности обработки смеси различие значений плотности для состава 1:3 и 1:9 составляет 7,6 %. Увеличение времени обработки смеси на 6 с во всем исследуемом диапазоне дает прирост прочности в 28-суточном возрасте примерно на 7–8 % для всех составов. Значение ранней прочности изменяется на 12–14 % между смесью, обработанной за 30 и 36 с. Затем на каждое последующее увеличение продолжительности обработки на 6 с это различие снижается на 1 % для всех составов. Изменение плотности бетона при варьировании времени обработки смеси фактически не изменяется и составляет 1–2 % при интервале в 6 с во всем исследуемом диапазоне для всех составов. Научная новизна. Впервые определены уравнения регрессии, связывающие продолжительность активации мелкозернистой бетонной смеси и ее состав с основными свойствами бетона. Практическая значимость. Получены уравнения регрессии и графические поверхности, по которым можно определить показатели технологических факторов, которые обеспечивают получение заданной ранней, стандартной прочности и средней плотности механоактивированного мелкозернистого бетона.

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Correlation between technological factors and basic properties of mechanically activated fine concretes

Purpose. Determination of conformities to law of influence of expense of components of easy concretes, which turn out on the basis of local afterproducts of industry, on their basic properties under conditions of enhanceable efficiency of the use of cement. Methodology. Experimental studies on optimization of structures and properties of concrete were carried out with use of mathematical planning experiments methods. All experiments were carried out on orthogonal design with three variables. Cement, water and additives PLKP-2 consumption were taken as varied factors. Findings. Vast experimental studies on determination of rational compositions of concrete mixtures were conducted with the use as fillers of granulated slag from iron and steel plant named after Petrovskiy and Dnepr sand, as binding agent Krivoy Rog portland-cement II/B-Ш-400, as filler fly-ash of Pridneprovsk Thermal Power Station. Efficiency coefficient of cement use was adopted as basic criterion of concrete composition rationality, it is determined on the relation of the attained durability per unit weight of used cement. For greater efficiency coefficient of cement use regularity of rational grain composition of components previously obtained was adopted, it is provided at a ratio of a large fraction consumption to medium and small 52:23:25, and their sizes are approximately 100:10:1. Experimental studies with use of mathematical planning experiments method were carried out. By results of their processing isofields were constructed according to the strength and effectiveness of the use of cement ratio of the studied factors. Originality. By strength comparative tests of hardened concrete with various local secondary resources, modified with complex plasticizer PLKP-2 additive, it was found that lightweight concrete with the density of 1700…1800 kg/m3 and concrete compressive strength from 5 to 20 MPa on the basis of granulated slag from the iron and steel plant named after Petrovskiy filled with fly-ash of Pridneprovsk Thermal Power Station during ensuring of rational grain composition of components with a ratio of major components of the fractions to medium and small 52:23:25 are the most effective. Practical value. Compositions of lightweight fine grained mixture based on granulated slag from the iron and steel plant named after Petrovskiy filled with fly-ash of Pridneprovsk Thermal Power Station and modified with complex plasticizer PLKP-2 additive were determined. They provide required concrete compressive strength within 5…10 MPa at a reduced cement consumption by approximately 20% as compared to the traditionally used compositions for these purposes.

http://stp.diit.edu.ua/article/download/17978/16906

Легкие бетоны с золой уноса Приднепровской ТЭС

The article deals with the tasks of efficient use of fillers and reusable industrial materials in the concretes with strength less than 20 MPa, the solution of which provides savings of cement consumption.

http://stp.diit.edu.ua/article/download/18466/16210

Reduction of concrete voidness mixes of rational selection of the grain components

The problems of utilization of the local industry after-products in the easy concretes and efficiency improvement  for using the cement by providing of rational grain composition of the components are presented.

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Designing of lightweight concrete with secondary resources in dnipropetrovsk region

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Mathematical modeling of water purification with filter

В. Петренко: ORCID 0000-0003-2201-3593; М. Нетеса: ORCID 0000-0003-1730-7642; О. Тютькін: ORCID 0000-0003-4921-4758; О. Громова: ORCID 0000-0002-5149-4165; В. Козачина: ORCID 0000-0002-6894-5532

/pdf/modeling-of-waste-water-treatment-in-vertical-settler-3wcy9s2zx2.pdf

M. I. Netesa

Papers

Легкие бетоны с золой уноса Приднепровской ТЭС

Reduction of concrete voidness mixes of rational selection of the grain components

Designing of lightweight concrete with secondary resources in dnipropetrovsk region

Mathematical modeling of water purification with filter

Modeling of waste water treatment in vertical settler