scholarly journals The effect of added high-iron slag on the frost resistance of cement compositions

2021 ◽  
Vol 263 ◽  
pp. 01012
Author(s):  
Gennadiy Ovcharenko ◽  
Ekaterina Ibe
Keyword(s):  
Frost Resistance ◽  
Building Materials ◽  
Ferric Iron ◽  
Mineralogical Composition ◽  
Cement Stone ◽  
Hardened Cement ◽  
High Iron ◽  
Iron Slag ◽  
Dispersed Phases ◽  
Correct Structure

Currently, it is of particular importance to study the possibility of increasing the durability of composite building materials by regulating the chemical and mineralogical composition. In this aspect, it is rational to consider the issues of increasing the frost resistance of cement concrete. It is known that to improve this property in concrete, it is necessary to create the correct structure of the hardened cement stone. The work aims to study the process of clogging the pores of a cement stone due to the formation of finely dispersed phases - ferrihydrite - in the process of hydration of composite Portland cement with the addition of high-iron slag of the established chemical composition. The paper analyzes the chemical and phase composition of concretes obtained based on of slag-containing binders with high values of frost resistance. It is shown that, based on this slag, concrete with frost resistance of 500 cycles has been obtained. Analysis of the hydration products showed that finely dispersed ferrihydrite of ferric iron are formed in the cement stone, which increases the density of concrete, plugging the defects in the microstructure of the C-S-H gel.

scholarly journals The use of amorphous silica-alumina-based additive in the adhesive dry mixes of building materials

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Loganina V. I. ◽  
Zhegera Ch.V.
Keyword(s):  
Frost Resistance ◽  
Building Materials ◽  
Chemical Elements ◽  
Physical And Mechanical Properties ◽  
Adhesive Layer ◽  
Vertical Surface ◽  
Cement Stone ◽  
Plastic Strength ◽  
Silica Alumina ◽  
Amorphous Aluminosilicate

Proved the possibility of using amorphous aluminosilicate as a modifying agent for the adhesive dry mixes. Are given the data on the microstructure and chemical composition of the amorphous aluminosilicates. Installed , that the microstructure of the synthetic additives is characterized by particles of round shape, dimensions 5,208-5,704 μm, Also there are particles of elongated shape in size 7.13-8.56 μm. Predominate chemical elements O, Si, Na, S, and Al in quantity 60.69%, 31.26%, 24.23%, 18.69% and 8.29% respectively. Described the character changes in the rheological properties of cement-sand mortar, depending on the percentage of additives. Determined, that the introduction in the cement-sand mortar the additive based on amorphous aluminosilicate leads to higher values of plastic strength. Are given the model of cement stone strength using synthetic additives in the formulation. The results of the evaluation of the frost resistance of cement-based tile adhesives with the use of amorphous aluminosilicates as a modifying additive are presented. In the article is determined the mark on frost resistance of tile glue and frost resistance of the contact zone of tile glue. The evaluation of the performance properties of the layer of tile adhesive on the basis of cement, dry mixes. The calculation of the value of displacement of the adhesive layer made on the basis of the developed recipes cement dry mixes applied to a vertical surface. Experimental data obtained values of displacement tiles relative to the substrate. Described the results of physical and mechanical properties of tile adhesive made on the basis of the developed adhesive dry mix formulations.

scholarly journals INFLUENCE OF MICROSTRUCTURE OF HYDRATE PHASES OF CEMENT STONE ON CONCRETE DURABILITY

2021 ◽  
Vol 6 (3) ◽  
pp. 8-18
Author(s):  
B. Trofimov ◽  
K. Shuldyakov ◽  
A. Mahmudov
Keyword(s):  
Reinforced Concrete ◽  
Cement Paste ◽  
Frost Resistance ◽  
Concrete Structures ◽  
Air Entrainment ◽  
Cement Stone ◽  
Hardened Cement ◽  
Reinforced Concrete Structures ◽  
Hardened Cement Paste ◽  
Structural Element

One of the main problems in modern concrete science is the low durability of reinforced concrete structures and constructions, especially those located in harsh climatic conditions and saturated with marine or mineralized water. Existing standards guide designers and builders to increase the density of concrete with increasing degree of aggressive impact, as well as through cyclical freezing of concrete structures, which taken as the main indicator of durability, air entrainment is mandatory. The problem is not only the provision of high frost resistance of concrete, but also finding a method of controlling it, which, as a rule, takes quite a long time. The destruction of concrete during cyclical freezing occurs not only due to the formation of ice in the pores of concrete, but also as a result of temperature stresses in concrete with ice, as well as the washing out of portlandite and aging of the cement gel – the main structural element of hardened cement paste. This means that the durability of the concrete can be ensured by maintaining the finely dispersed structure of the hardened cement paste, preventing crystallization of the gel from external influences or increasing its basicity. It is shown that only water reduction and pozzolanization, which provides residual portlandite content in Portland cement concrete stone 2–5 % by weight ensure the achievement of increased durability of concrete, reinforced concrete structures and constructions. A method is proposed to assess the stability of hydrate phases as well as the relationship between the durability and frost resistance of concrete.

THE FEATURES OF BIODESTRUCTION PROCESSES OF THE SURFACES OF HYDRAULIC ENGINEERING CONSTRUCTIONS

2017 ◽  
Author(s):  
Marina Vasilenko ◽  
Marina Vasilenko ◽  
Elena Goncharova ◽  
Elena Goncharova ◽  
Yury Rubanov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Environmental Factors ◽  
Food Chain ◽  
Building Materials ◽  
Microbial Growth ◽  
Mineralogical Composition ◽  
Mechanical Action ◽  
Chemical Processes ◽  
Hydraulic Engineering ◽  
Optimal Conditions

The surfaces of building materials of hydrotechnical constructions undergo the process of algae biofouling. The degree of damage depends on the environmental factors that are affect-ed by the level of anthropogenic load areas. Modeling the biofouling process of concrete with algae under laboratory conditions has allowed determining their impact on the building ma-terial, accompanied by changes in chemical and mineralogical composition of the surface of products. The microscopic examination of sample’s surfaces and evaluation of the effective-ness of various ions leaching from building materials shows the results of "algal attack" relat-ed to the acceleration of biodegradation of materials under the influence of aggressive meta-bolic products, mechanical action neoplasms, creating optimal conditions for the development of subsequent aerobic microbial decomposers. To clarify the nature of chemical processes in the system “algocenosis – concrete” the changes of chemical and phase (mineralogical) com-position of the surface layer of concrete sample were studied. The effect that algae produce on hydraulic engineering constructions is due to the fact that these organisms, belonging to phototrophs and standing at the beginning of the food chain, initiate new microbial growth.

THE FEATURES OF BIODESTRUCTION PROCESSES OF THE SURFACES OF HYDRAULIC ENGINEERING CONSTRUCTIONS

2017 ◽  
Author(s):  
Marina Vasilenko ◽  
Marina Vasilenko ◽  
Elena Goncharova ◽  
Elena Goncharova ◽  
Yury Rubanov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Environmental Factors ◽  
Food Chain ◽  
Building Materials ◽  
Microbial Growth ◽  
Mineralogical Composition ◽  
Mechanical Action ◽  
Chemical Processes ◽  
Hydraulic Engineering ◽  
Optimal Conditions

The surfaces of building materials of hydrotechnical constructions undergo the process of algae biofouling. The degree of damage depends on the environmental factors that are affect-ed by the level of anthropogenic load areas. Modeling the biofouling process of concrete with algae under laboratory conditions has allowed determining their impact on the building ma-terial, accompanied by changes in chemical and mineralogical composition of the surface of products. The microscopic examination of sample’s surfaces and evaluation of the effective-ness of various ions leaching from building materials shows the results of "algal attack" relat-ed to the acceleration of biodegradation of materials under the influence of aggressive meta-bolic products, mechanical action neoplasms, creating optimal conditions for the development of subsequent aerobic microbial decomposers. To clarify the nature of chemical processes in the system “algocenosis – concrete” the changes of chemical and phase (mineralogical) com-position of the surface layer of concrete sample were studied. The effect that algae produce on hydraulic engineering constructions is due to the fact that these organisms, belonging to phototrophs and standing at the beginning of the food chain, initiate new microbial growth.

scholarly journals POROSITY PARAMETERS OF CEMENT STONE CONTAINING CHEMICAL ADMIXTURES OF DIFFERENT PURPOSE / CEMENTINIO AKMENS SU SKIRTINGOS PASKIRTIES CHEMINIAIS PRIEDAIS PORINGUMO RODIKLIAI

2013 ◽  
Vol 5 (5) ◽  
pp. 530-535
Author(s):  
Lukas Venčkauskas ◽  
Mindaugas Daukšys
Keyword(s):  
Cement Paste ◽  
Cement Stone ◽  
Hardened Cement ◽  
Closed Porosity ◽  
Hardened Cement Paste ◽  
Chemical Admixtures ◽  
Average Size ◽  
The Impact ◽  
Plasticizing Admixture

The conducted research has established a complex influenceand the impact of separate chemical admixtures of differentpurpose on the parameters of the porosity of hardened cementpaste such as open and closed porosity, the average size of poresand the rates of pore inequality. According to the parametersof the porosity of hardened cement paste, on the basis of A. E.Sheikin’s methodology, the number of freezing-thawing cycleswas predicted. This research used plasticizing, viscosity modifyingand antifoaming admixtures. It has been found that, when theamount of plasticizing admixture in cement paste (W/C–0.45) isconstant and makes 1.1% of the cement mass, and the amountof viscosity modifying and antifoaming the admixture increasesfrom 0.1 to 0.6% and from 0.05 to 0.3% respectively, the openporosity of hardened cement paste varies between 30.21% and31.06%, while closed porosity varies between 5.39% and 6.22%.When the amount of the plasticizing admixture in cement paste(W/C–0.45) exceeds 1.1% of the cement mass, the open porosityof hardened cement paste increases by 1.4 times and closedporosity decreases by 2.5 times. While adding 0.1% of the viscositymodifying admixture to cement paste, the open porosityof hardened cement paste is increased by 1.5 times and closedporosity decreases by 2.4 times. The amount of 0.05% of thecement mass of the antifoaming admixture results in the increasedopen porosity of hardened cement paste by 1.5 times and reducedclosed porosity by 3.5 times. Santrauka Tyrimo metu nustatyta kompleksinė bei atskirų skirtingos paskirties cheminių priedų įtaka cementinio akmens poringumo rodikliams – atvirajam ir uždarajam poringumui, vidutinio porų dydžio ir porų vienodumo rodikliams. Tyrimuose naudoti cheminiai priedai: plastifikuojantis, klampą modifikuojantis ir mišinyje susiformavusias oro poras suardantis priedas. Nustatyta, kad cemento tešloje (V/C – 0,45) esant pastoviam plastifikuojančio priedo kiekiui – 1,0 % cemento masės, klampą modifikuojančio priedo kiekiui kintant nuo 0,1 iki 0,6 %, o mišinyje susiformavusias oro poras suardančio priedo kiekiui kintant nuo 0,05 iki 0,3 %, cementinio akmens atvirasis poringumas svyruoja nuo 30,21 iki 31,06 %, o uždarasis – nuo 5,39 iki 6,22 %. Cemento tešloje viršijus plastifikuojančio priedo 1,1 % cemento masės, cementinio akmens atvirasis poringumas padidėja apie 1,4 karto, o uždarasis poringumas sumažėja apie 2,5 karto. Pridėjus į tešlą 0,1 % cemento masės klampą modifikuojančio priedo, cementinio akmens atvirasis poringumas padidėja apie 1,5 karto, uždarasis poringumas sumažėja apie 2,4 karto. Oro poras suardančio priedo kiekis 0,05 % cemento masės cementinio akmens atvirąjį poringumą padidina apie 1,5 karto, uždarąjį poringumą sumažina apie 3,5 karto.

scholarly journals Physicochemical Properties of Handere Clays and Their Use as a Building Material

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yasin Erdoğan
Keyword(s):  
Physicochemical Properties ◽  
Building Materials ◽  
Raw Materials ◽  
Organic Matter Content ◽  
Volcanic Glass ◽  
Mineralogical Composition ◽  
Matter Content ◽  
Loss On Ignition ◽  
X Ray Diffraction ◽  
Clay Deposits

Handere clay deposits were discovered at Adana in Turkey. These clay units primarily consist of uncoloured claystone, pebbly sandstone, sandstone, siltstone, and mudstone marl and include gypsum lenses and clay levels of various thicknesses in places. The physicochemical properties of these clays have been investigated by different techniques including Scanning Electron and Elemental Analysis (SEM and EDS), mineralogical analyses, chemical and physical analyses, X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), and Atterberg (Consistency) Limits Test. The mineralogical composition deduced from XRD is wide (smectite + palygorskite + illite ± feldspar ± chlorite ± quartz ± calcite ± serpentine) due to the high smectite contents (≈85%). SEM studies reveal that smectite minerals are composed of irregular platy leaves and show honeycomb pattern in the form of wavy leaves in places. The leaves presenting an array with surface edge contact are usually concentrated in the dissolution voids and fractures of volcanic glass. Organic matter content and loss on ignition analysis of raw materials are good for all the studied samples. In summary, Handere clays can be used as building materials in bricks, roof tiles, and cement and as a binder.

scholarly journals Use of Ash-and-Slag Wastes after Burning of Fine-Dispersed Coal-Washing Wastes

2018 ◽  
Vol 41 ◽  
pp. 01042
Author(s):  
Vasilii Murko ◽  
Veniamin Khyamyalyainen ◽  
Marina Baranova
Keyword(s):  
Power Plants ◽  
Building Materials ◽  
Negative Impact ◽  
Mineralogical Composition ◽  
Unburned Carbon ◽  
Crushed Rock ◽  
Low Carbon ◽  
Technological Parameters ◽  
Coal Fuel ◽  
Granulated Slag

Effective utilization of ash-and-slag waste generated by coalfired power plants can help significantly to reduce the negative impact on the environment and improve their economic performance. Studies have been made of the mineralogical composition of ash-and-slag wastes obtained after the combustion of water-coal fuel based on fine-dispersed coal-washing waste (filter cake) in a specially designed boiler with a vortex combustion system. The possibility of effective use of ash-and-slag wastes for the production of building materials, primarily mortar mixes, widely used for mining works on mine openings, laying the worked out space, etc. (high content of silicon oxide and aluminum oxide is combined with a low carbon content in other words a negligible unburned carbon loss). The optimum percentage ratio of the initial components of the filling mixture based on ash-and-slag wastes and crushed rock (granulated slag) has been established. The results of experimental tests of hardening tabs on the strength under uniaxial compression are presented. It has been established that a sample containing 18% of ash-and-slag wastes, 33% of a granulated slag and 19% of cement, corresponds to the required technological parameters for the strength and cement content.

scholarly journals Concrete based on sulfur binder being modified with inorganic additives

2018 ◽  
Vol 212 ◽  
pp. 01013
Author(s):  
Vadim Balabanov ◽  
Victor Baryshok ◽  
Nikita Epishkin
Keyword(s):  
Frost Resistance ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Strength Properties ◽  
Climatic Conditions ◽  
Freezing And Thawing ◽  
Concrete Mixtures ◽  
Irkutsk Region ◽  
Water Saturated

The sharply continental climate of the Irkutsk region is characterized by wide temperature intervals throughout the year. The repeated cyclicity of freezing and thawing of building materials in the water-saturated state influences the change in technical characteristics and the durability of concrete products and structures. The concrete products’ features in such climatic conditions create the need for the production of concretes with improved indicators of physical and mechanical properties. The effect of modifying additives on the technological characteristics of sulfur concrete is established. The effect of all elements of sulfur concrete on its strength and frost resistance. The composition of sulfuric concrete is obtained, which meets all the requirements and also has high strength and increased frost resistance. Formulations with a certain ratio of structural sulfuric concrete mixtures were developed. As a result of the use of technical sulfur in the composition of concrete products, the problem of utilizing annually accumulating reserves of technical sulfur is partially solved. The strength properties of sulfuric concretes easily compete with high-quality brands of concrete, special types of concretes that have in their composition additives.

scholarly journals Strengthening the pavement bases through the use of stabilizing additives

2018 ◽  
Vol 5 (4) ◽  
Author(s):  
Dmitry Stroev ◽  
Sergey Sizonets ◽  
Vanik Kazaryan
Keyword(s):  
Road Construction ◽  
Mineralogical Composition ◽  
High Water ◽  
Base Layer ◽  
Cement Stone ◽  
Structure And Properties ◽  
Residual Deformations ◽  
Positive Properties ◽  
Mineral Binder ◽  
Structural Base

The experience of recent years of road operation shows that one of the ways to reduce the accumulation of residual deformations in the layers of road construction, expressed in rutting, the appearance of a grid of cracks and other types of transverse and longitudinal irregularities, is used in the base layers of pavements reinforced with mineral binders of crushed-stone-gravel-sandy mixtures (HGPS). The strength and deformability of hardened HGPS is determined mainly by the structure and properties of the cement stone, which holds the aggregate grains in place. The structure and properties of reinforced HGHPs depend on: the mineralogical composition, the water-cement ratio, the fineness of the cement, the age, the preparation and hardening conditions, or the addition of additives. With the introduction of additives, you can significantly change the strength and deformability of reinforced HGPS. Currently, stabilizing additives are widely used, the introduction of which allows to provide high water resistance, crack resistance and durability of the structural base layer. At the same time, a reinforced mixture with the use of additives has not only all the positive properties of HGPS on portland cement, but also eliminates its negative sides: low values of compressive strength, tensile strength in bending, and large shrinkage deformations. Based on the above, the introduction of stabilizing additives in fortified HGPS seems to be fruitful. As an additive, the stabilizer «ARMADOR» was used. The additive is a dry bulk mixture based on polymers, salts of alkali and alkaline earth metals. With the introduction of the stabilizer «ARMADOR», the physico-mechanical parameters increase in the composition of the reinforced material. This stabilizer creates strong crystallization and coagulation bonds, the use of which is recommended in conjunction with a mineral binder.

scholarly journals Comparative Study of Roman Iron Slags Discovered in the Roman Auxiliary Fort and Settlement of Călugăreni

2018 ◽  
Vol 1 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Enikő Bitay ◽  
Irén Kacsó ◽  
Szilamér Péter Pánczél ◽  
Erzsébet Veress
Keyword(s):  
Comparative Study ◽  
Ftir Spectroscopy ◽  
Optical Microscopy ◽  
Mineralogical Composition ◽  
Iron Slag ◽  
Eastern Border ◽  
The Military ◽  
Archaeological Excavations

Abstract Iron slag samples unearthed at the eastern border of Roman Dacia, in the auxiliary fort and the military settlement of Călugăreni (Mikháza) are investigated by macroscopic inspection, optical microscopy (OM) and FTIR spectroscopy in order to comparatively characterize their macro- and microstructure as well as their mineralogical composition. During the recent archaeological excavations, a large number of iron artefacts were discovered together with a great quantity of iron slag fragments. The present paper focuses on the data obtained from 17 slag samples.

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