scholarly journals FEATURES OF THE PROCESSES OF HYDRATION OF BINDING COMPOSITIONS USING WASTE OF EXPANDED PERLITE SAND

2020 ◽  
Vol 5 (11) ◽  
pp. 75-88
Author(s):  
L. Zagoronyuk ◽  
S. Rahimbaev ◽  
D. Sumskoy ◽  
V. Ryzhikh
Keyword(s):  
Mechanical Activation ◽  
Chemical Activation ◽  
High Strength ◽  
Cement Stone ◽  
Expanded Perlite ◽  
Hydration Products ◽  
Special Effect ◽  
Degree Of Hydration ◽  
Number Of Factors ◽  
Calcium Hydrosilicates

The results of studying the processes of hydration of binder compositions obtained at different ratios of cement and waste of expanded perlite sand (from 5 to 10%), in a vortex jet mill, under different modes of mechanical and chemical activation - from one to three passes are presented. Comprehensive studies of hydration products by X-ray phase analysis and electron microscopy indicate that the use of highly dispersed wastes from the production of expanded perlite sand in binding compositions allows an increase in the content of hydrated neoplasms due to an increase in the degree of hydration of the main clinker phases, as well as due to the pozzolanic activity of these wastes. The contact zone between the hydrated compounds and the remnants of the grains of the original cements has a special effect on the formation of a high-strength structure of the cement stone. The structure formation of a cement stone depends on a number of factors, which can be influenced by various technological methods. When designing compositions of cement composites, it is necessary to ensure that hydration products in the created system are present along with low-basic calcium hydrosilicates and high-basic ones. Their ratio should be such that carbonization does not reduce the volume of the formed crystalline phase of the cement stone. The composition of the hydration products determines the level of supersaturation of the solution, the type and number of impurities soluble in water, the duration of the hydration process, etc. The chemistry of the reactions of the hydrated system changes accordingly. It is found that the intensity of the diffraction maxima, indicating the presence of highly basic calcium hydrosilicates in the compositions that underwent mechanical activation, increases by 18% in comparison with the ordinary PC. The strength characteristics of Portland cements, which have undergone mechanical activation, increase up to 15% compared to the original PC. The most rational binder composition is established in terms of composition (No. 6), mechanical activation and maximum compressive strength at 28 days of age – 69.1 MPa.

scholarly journals X-ray diffraction of concrete composites of high structural strength and density

2021 ◽  
Vol 22 (4) ◽  
pp. 746-749
Author(s):  
Oleksandr Sumariuk ◽  
Ihor Fodchuk ◽  
Volodymyr Romankevych
Keyword(s):  
Compressive Strength ◽  
Structural Strength ◽  
Cement Stone ◽  
Qualitative Composition ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
Calcium Hydrosilicates ◽  
Main Factors

Аn analysis of the structure formation of concrete composites, compressive strength of which exceeds 120 MPa and a quantitative analysis of their qualitative composition and hydration products by X-ray diffraction, x-ray spectral analysis. The main factors affecting the physicomechanical parameters of the complex of various nanofillers and the formation of a denser cement stone structure, which mainly includes calcium hydrosilicates, calcium silicate hydroaluminates and hydroaluminates of various basicity, are studied.

scholarly journals MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL

2017 ◽  
Vol 2 (3) ◽  
pp. 9-18 ◽  
Author(s):  
Золотых ◽  
Sergey Zolotykh ◽  
Сумской ◽  
Dmitriy Sumskoy ◽  
Загороднюк ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Portland Cement ◽  
Mechanical Activation ◽  
Cement Stone ◽  
Mineral Filler ◽  
Hydration Products ◽  
Dense Structure ◽  
Additional Support ◽  
Effective Use

Zagorodnuk L.H., Sumy D.A., Golden S.V., Kaneva E.V. MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL By electron microscopy to study the microstructure of the cement stone made from Portland cement and activated binders of the compositions in the vortex jet mill. It was found that the open pores of the cement and cementitious compositions prepared using perlite fillers, always filled with tumors, at different stages of collective growth. The microstructure of cementitious compositions has a dense structure by rationally selected composition, effective use of mineral filler - perlite waste, creating additional support for the formation of the internal microstructure of the composite, mechanical activation raw mixture, allowing to obtain composites with desired properties.

Improvement of Wood-Cement Composition Properties with Microsilica Additive

2020 ◽  
Vol 992 ◽  
pp. 162-167
Author(s):  
E.Yu. Gornostaeva ◽  
N.P. Lukuttsova ◽  
D.I. Dryazgov
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Silicon Dioxide ◽  
Cement Hydration ◽  
Cement Stone ◽  
Hydration Products ◽  
Maximum Increase ◽  
Calcium Hydrosilicates ◽  
Calcium Silicates ◽  
Composition Properties

The properties and microstructure of wood-cement compositions (WCC) with microsilica (MS) additive for the manufacture of small-pieces wall products are studied. The extreme dependences of mean density, thermal conductivity and compressive strength on the content of microsilica additive are established. The mechanism of microsilica effect on wood-cement compositions is offered. Two interrelated factors (chemical and physical) could be distinguished at that. The first factor includes mainly the interaction of silicon dioxide with lime having released during hydration of calcium silicates, i.e. pozzolatic process. The second factor lies in the compaction of wood-cement compositions and the cement stone structure by means of cement hydration products and silica particles. It is established that introducing 20% of microsilica in the composition results in the maximum increase in ultimate compression strength (3 times). It can be explained not only by forming calcium hydrosilicates, uniformly and densely covering the wood aggregate, but by compacting effect of spherical microsilica inclusions, filling the space between the new cement stone formations and wood aggregate.

Influence of Nanoscale Barium Hydrosilicates on Composition of Cement Stone

2016 ◽  
Vol 683 ◽  
pp. 90-94 ◽  
Author(s):  
Anna Nikolaevna Grishina ◽  
Evgeniy Valerjevich Korolev
Keyword(s):  
Composite Materials ◽  
Chemical Composition ◽  
Portland Cement ◽  
Cement Hydration ◽  
Experimental Investigations ◽  
Cement Stone ◽  
Hydration Products ◽  
Efficient Control ◽  
Calcium Hydrosilicates ◽  
Portland Cement Hydration

The development of new types of composite materials is an important aim for construction. Nanoscale admixtures allow efficient control of the composition and properties. Results of experimental investigations concerning effect of admixture of nanoscale barium hydrosilicates to the chemical composition of hydrated portland cement are discussed in the present work. It is shown that several key processes are taking place during nanomodification. Amount of portlandite in cement stone decreases, and there is also quantity growth of different calcium hydrosilicates CSH (I), CSH (II), riversideite and xonotlite. Influence of composition and storing time of barium hydrosilicates to the ratio of different portland cement hydration products is examined. It is found that admixture of barium hydrosilicates with gross formula BaO•26.47SiO2•nH2O stored for 28 days leads to both reduction of portlandite and accretion of hydrated phase.

scholarly journals CALCULATION AND SELECTION OF THE HIGH DENSITY AGGREGATES FROM CONCRETE SCRAP

2020 ◽  
pp. 18-28
Author(s):  
W. Albo Ali ◽  
R. Lesovik ◽  
A. Kharkhadin ◽  
A. Tolstoy ◽  
A. Ahmed ◽  
...  
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
High Density ◽  
Internal Stresses ◽  
Cement Stone ◽  
Degree Of Hydration ◽  
Calcium Hydrosilicates ◽  
New Type ◽  
High Base ◽  
Selection Of

Abstract. The new transdisciplinary science of geonics (geomimetics) is the theoretical basis for designing construction composites from fragments of destroyed buildings and structures. Technogenic and natural anomalies, military conflicts on planet Earth lead to destruction of cities. Utilization of fragments of destroyed buildings and structures for the production of building materials is relevant. The classification and scheme of using fragments of destroyed buildings and structures to obtain crushed stone, sand, solutions and concretes based on them is proposed. The densest packaging is calculated using the method of selecting high-density filler packaging developed at BSTU named after V.G. Shukhov. The results are tested on the raw materials of destroyed buildings and structures in Iraq, which consist mainly of reinforced concrete, ceramic bricks and limestone blocks. The presence of binder particles that are not fully hydrated in the concrete scrap, which are subsequently hydrated and participate in the curing of the composite with the formation of an additional number of crystalline neoplasms, and also accelerates the hardening of cement stone and increases the final strength of the material. Subsequently, in the previously created structure, as a result of continuing hydration, a new type of system parts is formed, organized in a certain way, due to the crystallization growth of pico -, nano - and micro-sized high-base calcium hydrosilicates, depending on the degree of hydration of concrete scrap. The following crystallization of previously formed phases leads to self-sealing of different parts of the system and their further self-organization, which ensures high final strength and water resistance of the material. This hydration mechanism gives a concrete structure with minimal internal stresses and volume deformations. The article discusses the methodology for the selection of high-density packing of aggregate from concrete scrap in the destroyed building and construction of Iraq. It is shown that the strength of the obtained samples with compacted aggregate is 31.3 % higher than that of samples prepared in the traditional way.

scholarly journals Peculiarities of hydration processes of cements containing natural zeolite

2015 ◽  
Vol 14 (1) ◽  
pp. 105-113 ◽  
Author(s):  
Khrystyna Sobol ◽  
Taras Markiv ◽  
Volodymyr Terlyha ◽  
Wojciech Franus
Keyword(s):  
Natural Zeolite ◽  
High Performance ◽  
Free Calcium ◽  
Cement Stone ◽  
Hydration Products ◽  
Chemical Methods ◽  
Cement Pastes ◽  
Blended Cements ◽  
Calcium Hydrosilicates ◽  
Physical And Chemical

In this study, properties and peculiarities of hydration processes as well as paste microstructure of blended cements containing 10% by weight of natural zeolite were investigated. Free calcium hydroxide content, crystalline hydration products and microstructural architecture of hydrated cement pastes were examined by physical and chemical methods. It was found that the addition of natural zeolite provides formation of an extra amount of fine crystalline ettringite and tobermorite-like calcium hydrosilicates of CSH (B) type in the mineral non-clinker part of Portland cement resulting in strength synthesis of cement stone with high performance properties.

scholarly journals Modified Light Concrete of High Strength

2018 ◽  
Vol 230 ◽  
pp. 03015
Author(s):  
Katerina Pushkarova ◽  
Kostiantyn Kaverin ◽  
Danilo Gadayuchyk
Keyword(s):  
Portland Cement ◽  
Lightweight Concrete ◽  
High Strength ◽  
Cement Stone ◽  
Complex Additive ◽  
Calcium Hydrosilicates ◽  
Increased Strength ◽  
Physical And Chemical ◽  
Kinetics Of ◽  
Resistance Coefficients

The study is devoted to the development of increased strength lightweight concrete based on Portland cement modified with a complex organo-siliceous additive containing a polycarboxylate superplasticizer and an active fine-ground siliceous component. The effect of this complex additive on the physical and chemical characteristics of the hydration and structure formation processes was investigated and it was shown that the high kinetics of the strength gain is provided by directional formation of low-basic calcium hydrosilicates, hydrogranates and plazolite, which are crystallo chemically similar to each other, and provide a dense and strength cement stone matrix. Modification by a complex additive makes possible to obtain concrete mixes with S4 consistency while a Portland cement consumption per 1m3 of not more than 330 kg, with a compressive strength of 55 MPa, watertightness up to W8, frost resistance up to F400, corrosion resistance coefficients Kc in the magnesium sulfate, sodium and ammonium solutions by 10 to 24%. The introduction of a complex additive also helps to reduce the relative shrinkage by 16 to 19% compared to the control composition, which has a positive effect on the durability of the resulting concrete.

scholarly journals MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL

2017 ◽  
Vol 2 (3) ◽  
pp. 9-18
Author(s):  
Сергей Золотых ◽  
Sergey Zolotykh ◽  
Дмитрий Сумской ◽  
Dmitriy Sumskoy ◽  
Лилия Загороднюк ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Portland Cement ◽  
Mechanical Activation ◽  
Cement Stone ◽  
Mineral Filler ◽  
Hydration Products ◽  
Dense Structure ◽  
Additional Support ◽  
Effective Use

Zagorodnuk L.H., Sumy D.A., Golden S.V., Kaneva E.V. MICROSTRUCTURE HYDRATION PRODUCTS BINDING COMPOSITION OBTAINED IN THE VORTEX JET MILL By electron microscopy to study the microstructure of the cement stone made from Portland cement and activated binders of the compositions in the vortex jet mill. It was found that the open pores of the cement and cementitious compositions prepared using perlite fillers, always filled with tumors, at different stages of collective growth. The microstructure of cementitious compositions has a dense structure by rationally selected composition, effective use of mineral filler - perlite waste, creating additional support for the formation of the internal microstructure of the composite, mechanical activation raw mixture, allowing to obtain composites with desired properties.

scholarly journals The influence of complex additives based on calcined clays and carbonate fillers on hydration products composition of blended cement stone

2021 ◽  
Vol 274 ◽  
pp. 04004
Author(s):  
Elizaveta Ermilova ◽  
Zagira Kamalova
Keyword(s):  
Blended Cement ◽  
Cement Industry ◽  
Cement Stone ◽  
Content Increase ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Calcined Clay ◽  
Calcium Hydrosilicates ◽  
Kaolinitic Clay

One of the most effective and recognizable way to solve energy and resource consumption problems in cement industry is the development of blended Portland cement with different combinations of mineral additives. The development of complex additives based on combination of calcined clays and limestone is one of the promising directions. The aim of this work was to study the influence of complex additives based on calcined kaolinitic clay with kaolinite content of 80 % and limestone with calcite content of 99 % on the blended cement stone hydration products at the age of 28 days. Using X-ray diffraction and differential scanning calorimetry the composition of blended cement stone hydration products was studied. It is established that the introduction of 20 % of the complex additive based on calcined clay and limestone leads to a significant decrease of the portlandite content, increase in the number of new growths in form of low-calcium hydrosilicates and calcium hidrocarboalumosilicates, stabilization of ettringiteand calcium hydrocarbosilicates in amorphous phase, that significantly increases the compressive strength. This effect was amplified due to the additional alumina provided by calcined clay reaction.

scholarly journals Action Time-Effect and Mechanism of Low-Calcium Fly Ash in Cement-Based Composites

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 681
Author(s):  
Na Yan ◽  
Qingqing Tang ◽  
Ying Zhang ◽  
Guowen Sun
Keyword(s):  
Fly Ash ◽  
Nitrogen Adsorption ◽  
Chemical Effect ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Degree Of Hydration ◽  
Surface Areas ◽  
Activity Effect ◽  
Low Calcium ◽  
Pore Size Distributions

This study was conducted in order to investigate when low-calcium fly ash plays a physical or chemical effect and what is the chemical effect proportion of low-calcium fly ash. Two types of low-calcium fly ash and quartz powder, with similar fineness as active and inert admixtures, were used as materials in this study. Under different water/binder ratios and hydration ages, the effects of the different types of admixtures and their dosages on the flexural and compressive strength of the composites were studied. X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption methods, in addition to an assessment of the degree of hydration of the fly ash, were employed to observe the hydration products at different ages, the microstructures of the hydration products, as well as their surface areas and pore size distributions. The results show that during the hydration period of 28 days, the low-calcium fly ash has a micro-aggregate filling physical effect. However, after 56 days, the hydration degree of fly ash begins to exceed 1%. This illustrates that the low-calcium fly ash has both the pozzolanic activity effect and micro-aggregate filling effect. In contrast, the low-calcium fly ash hydrated for 90 days is still dominated by the physical filling effect.

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