Leonid Dvorkin

Leonid Dvorkin
National University of Water and Nature · Constructing and Architect Institute

About

101
Publications
27,753
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
382
Citations
Citations since 2017
70 Research Items
339 Citations
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080
2017201820192020202120222023020406080

Publications

Publications (101)
Article
Full-text available
The paper deals with the effectiveness of various types of polymers (naphthalene formaldehyde, polycarboxylate, and lignosulfonate) as superplasticizers of concrete mixtures based on low-clinker slag Portland cement. Using the mathematical planning experimental method and statistical models of water demand of concrete mixtures with polymer superpla...
Article
Full-text available
The article proposes a method that considers the parameters of heat and moisture treatment of concrete when designing its composition. Based on the analysis of experimental data, formulas are proposed that allow taking into account the type and characteristics of cement, the characteristics of aggregates, the effect of temperature and duration of s...
Conference Paper
Full-text available
The article discusses the possibility of improving the properties of concrete made with composite ash-containing cement (CC) by introducing complex chemical additives. The pozzolanic activity of CC and its degree of hydration increases with the increasing dispersion of cement resulting from the introduction of a complex additive in the form of a po...
Article
The structure formation of hardened samples of gypsum and phosphogypsum binders (with a complex of additives) is investigated by X-ray diffraction analysis and electron microscopy. The influence of additives-modifiers on the composition of curing products and on the morphology of the hydrate formation – CaSO4·2H2O – is determined. X-ray diffraction...
Article
Full-text available
A set of experimental-statistical models has been obtained that makes it possible to predict the workability and strength of concrete on a composite binder, including the addition of dust from cement clinker kilns and granulated blast-furnace slag, as well as polycarboxylate superplasticizer Sika VC 225. The values of the critical water-cement rati...
Article
Full-text available
The article shows the effectiveness of the use of polymer additives for the production of fine-grained concrete mixtures and concretes based on using coal fly ash, which can be used as working mixtures for a 3D printer. Using mathematical planning of experiments, a set of experimental–statistical models was obtained that describes the influence of...
Article
Full-text available
In recent decades, most of construction activities have been taking place in developing countries such as the Middle East and North Africa region. The expansion in infrastructure has great impact in the technological, social, economic and environmental transformation of this region. Construction sector contribution to Gross Domestic Product (GDP) v...
Article
Full-text available
Today, numerous design solutions require joining thin-walled sheets or profiles as the traditional methods of welding with a consumable electrode in gas shielding, most often used in production processes, do not work well. The reason for this is that a large amount of heat is supplied to the joint, causing numerous welding deformations, defects, an...
Article
Full-text available
The paper deals with composition design of self-compacting concrete containing blast furnace granulated slag and polycarboxylate type superplasticizer in a wide range of concrete strength classes. Optimal superplasticizer content, cement, and blast furnace slag consumptions are obtained from the viewpoint of minimum water demand and water-cement ra...
Article
Full-text available
The article presents a set of experimental-static models of the properties of fine-grained concretes on a cement–slag binder and quartz sand with the addition of a hardening accelerator made on a 3D printer. The influence of the factors of the composition of the mixture and the effects of their interaction on the studied properties of concrete was...
Article
Full-text available
There are no standards for testing the properties of 3D-printed materials; hence, the need to develop guidelines for implementing this type of experiment is necessary. The work concerns the development of a research methodology for interlayer bond strength evaluation in 3D-printed mineral materials. In additive manufactured construction elements, t...
Article
Full-text available
Ground blast-furnace slag is one of the waste products available in Ukraine and other countries. It is obtained at metallurgical enterprises in huge quantities and can be efficiently used for concrete production. The article is devoted to obtaining experimental-statistical models of the influence of technological factors that determine the composit...
Article
Full-text available
This article presents experimental studies that have shown the effectiveness of using a composition of fly ash and metakaolin as an active mineral admixture to cement. It is shown that composite ash–metakaolin additives (AMAd) have on the one hand increased pozzolanic activity and surface energy, and, on the other hand, moderated water demand and p...
Conference Paper
Full-text available
Composite admixtures which include active pozzolanic components and high-range water reducers, allows to obtain high-strength, particularly dense and durable concrete to achieve a reduction in resources and energy consumption of manufacturing.Zeolite, containing a significant amount of active silica, can serve as one of the alternative substances t...
Article
An experimental investigation was conducted in order to study the water absorption, mechanical performance, thermal properties and durability of hybrid hemp-rapeseed composite materials. The hybrid composite material is made with 50% hemp shives and 50% rapeseed fibres. The purpose of this study is to investigate the influence of the incorporation...
Article
Full-text available
The article is devoted to the issues of obtaining pressed building materials based on dihydrate phosphogypsum. Dihydrate phosphogypsum after mechanical activation in a ball mill acquires the ability to harden in pressed specimens. After activation of dihydrate phosphogypsum in a ball mill and its pressing at a pressure of 30 MPa, the strength of sp...
Conference Paper
An experimental investigation was conducted in order to study the water absorption, mechanical performance, thermal properties and durability of hybrid hemp-rapeseed composite materials. The hybrid composite material is made with 50% hemp shives and 50% rapeseed fibres. The purpose of this study is to investigate the influence of the incorporation...
Article
Problem and goal. The results of research of influence of dispersed reinforcement on properties of concrete semi-dry mixes, their ability to consolidation by vibropressing and strength characteristics of the received concrete are resulted. Metodology and result. In the first stage of research, steel anchor fiber was used as a dispersed fiber, the s...
Chapter
The article presents the methodology of designing the composition of fine-grained concrete, taking into account the method of compaction, the parameters of the aggregate and the binder obtained on the basis of a complex of experimental studies. The results of studies of the effect of the type of concrete mixtures and their method of compaction on t...
Article
Full-text available
Adding different fiber types may yield improvement of steel fiber reinforced concrete (SFRC) features. Therefore, the investigation of hybrid fiber reinforced concrete (HFRC) mechanical properties is relevant. The effect of adding hybrid steel and basalt fiber on the mechanical properties of fine-grained concrete is studied. It is shown that hybrid...
Article
Full-text available
The paper presents the results of experimental studies of the possibility of obtaining modified supersulfate cements (SSC) with improved physical and mechanical properties on lowalumina blast-furnace granular slags. It has been shown in comparative experimental tests of the effect of admixtures of various sulfate activators that the highest strengt...
Article
Full-text available
The paper gives coverage on the properties of reactive powder concrete, incorporating metakaolin and fly ash and polyacrylate superplasticizer. There are given results of comparative research of reactive powder concrete (RPC) containing silica fume. There are also considered the impact of curing conditions on the strength of RPC specimens. The comb...
Article
Full-text available
The paper considers the influence of β-hemihydrate and phosphogypsum binder on the properties of dry pack mortars for self-levelling floors. As preliminary research demonstrated that adding to phosphogypsum (PG) admixtures of lime and PA or PC superplasticizer permits to obtain binder with high compressive (up to 24 MPa) and bending strength (up to...
Article
The issue of ensuring the construction of materials and products, necessary quality characteristics and durability, is associated with the solution of many problems arising both in the construction industry enterprises and in the conditions of a construction site. Most of these (construction-technological) problems are solved due to the rational ch...
Article
Full-text available
Design of optimal concrete compositions with specified quality indicators at minimal cost still remains one of the most actual problems. The paper deals with methodology for designing optimal fiber reinforced concrete composition using experimental-statistical models of concrete properties. The obtained mathematical models for compressive and flexu...
Conference Paper
Full-text available
The paper considers the influence of β-hemihydrate and phosphogypsum binder on the properties of dry pack mortars for self-levelling floors. As preliminary research demonstrated that adding to phosphogypsum (PG) admixtures of lime and PA or PC superplasticizer permits to obtain binder with high compressive (up to 24 MPa) and bending strength (up...
Article
The article contains a theoretical analysis of the proposed parameters of the structure of concrete, which determine its frost resistance. Experimental studies have been carried out that made it possible to obtain a calculation formula for predicting the frost resistance of concrete depending on the ratio of the volumes of open and closed pores in...
Conference Paper
The paper considers the influence of β-hemihydrate and phosphogypsum binder on the properties of dry pack mortars for self-levelling floors. As preliminary research demonstrated that adding to phosphogypsum (PG) admixtures of lime and PA or PC superplasticizer permits to obtain binder with high compressive (up to 24 MPa) and bending strength (up to...
Article
The paper deals with experimental results on temperature and curing duration influence on strength properties of high strength concrete (HSC). Dependences for calculating strength of high strength concrete at 12 h, 1, 7 and 28 days are developed for normal hardening conditions. Equations, allowing considering curing temperature in diapason between...
Article
Full-text available
Metakaolin (MK) is one of the most effective mineral admixtures for cement-based composites. The deposits of kaolin clays are wide-spread in the world. Metakaolin is comparable to silica fume as an active mineral admixture for cement-based composites. In this paper, the rheological and mechanical properties of cement paste containing metakaolin are...
Article
Full-text available
The increase of the consumption of gypsum products in construction industry with a limited amount of natural gypsum deposits requires alternative sources of gypsum-containing raw materials. In some countries which have fertilizers industry plants, the problem can be solved using industrial wastes, e.g. phosphorgypsum – a byproduct of fertilizers’ p...
Article
Full-text available
Metakaolin (MK) is one of the most effective mineral admixtures for cement-based composites. The deposits of kaolin clays are wide-spread in the world. Metakaolin is comparable to silica fume as an active mineral admixture for cement-based composites. In this paper, the rheological and mechanical properties of cement paste containing metakaolin are...
Article
Full-text available
The increase of the consumption of gypsum products in construction industry with a limited amount of natural gypsum deposits requires alternative sources of gypsum-containing raw materials. In some countries which have fertilizers industry plants, the problem can be solved using industrial wastes, e.g. phosphorgypsum – a byproduct of fertilizers’ p...
Article
Using stone crushing waste products allows more rational and complex use of mineral resources and increases the ecological safety level of quarry works and production of stone materials. This paper focuses on an experimental investigation of the composition effect of vibro-pressed fine-grained concrete incorporating granite siftings on compression...
Chapter
Full-text available
In recent years, interest has been growing in the use of gypsum as one of the most sustainable mineral binders. This chapter covers a range of gypsum products based on different modifications of gypsum binders.
Book
Full-text available
The work is devoted to the creation of theoretical, experimental and methodological foundations of modern building materials and structural systems for the construction of affordable housing and infrastructure. The monograph develops the physical-chemical and thermodynamic bases for the synthesis of minerals and their hydration to produce artificia...
Article
Full-text available
Gypsum binders are low-energy ecologically safe materials. Along with undoubted advantages, related to high sustainability, they have substantial disadvantages, which include low strength, low water resistance, rapid setting and hardening. α-hemihydrate gypsum binders have significantly higher strength than β-hemihydrate, thus the manufacturing...
Article
The paper deals with results of experimental research on cement glue mortars containing non-milled fly ash and organic-mineral modifiers are given. The organic-mineral modifiers (OMM) include finely dispersed additives like microsilica or milled fly ash and organic substances (naphthalene formaldehyde superplasticizers and redispersed polymers). Gl...
Book
Mathematical planning presents methods of experiments for the decision of tasks of concrete compositions design with the set of given properties presented in this book. The procedures for obtaining different types of mathematical models and their technological analysis are presented. Examples of application of the mathematical planning methods of e...
Article
Existing design approaches for steel fiber reinforced concrete composition practically do not consider the interaction between the concrete components. It decreases the design efficiency and accuracy. The paper deals with methodology for design of optimal steel fibered fine-grained concrete composition based on stiff mixtures. Such concrete is used...