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.

Study of the pozzolanic activity and hydration products of cement pastes with addition of natural zeolites

Clay Minerals ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 241-250 ◽  
Author(s):  
V. Lilkov ◽  
O. Petrov ◽  
V. Petkova ◽  
N. Petrova ◽  
Y. Tzvetanova
Keyword(s):  
Surface Area ◽  
Cement Paste ◽  
Chemical Reactions ◽  
Natural Zeolite ◽  
Early Stage ◽  
Pozzolanic Activity ◽  
Large Surface Area ◽  
Natural Zeolites ◽  
Hydration Products ◽  
Cement Pastes

AbstractThis paper presents results from comparative thermogravimetric, calorimetric and pozzolanic activity analyses of five natural zeolite samples from Bulgaria, Slovakia, Philippines, USA and North Korea. The zeolites actively participate in the hydration processes of cement. Their activity in the early stage of hydration is based mainly on the large surface area of the particles while, in the later stages of activation, chemical reactions occur between the products of the hydration of cement and the soluble SiO2 that is present in the bulk of the zeolites. It has been shown that in all cement pastes which contain zeolite additives, the quantity of portlandite is lower than that in pure cement paste or is even totally absent. The amounts of hydration products are greater when 30% zeolite is used than when 10% zeolite is added (excluding the sample with chabazite). The lowest pozzolanic activity is shown by chabazite, which possessed the lowest SiO2/Al2O2 ratio.

scholarly journals Investigation of the structure of cement conglomerates

2021 ◽  
Vol 266 ◽  
pp. 03005
Author(s):  
D. N. Shabanov ◽  
E. Trambitsky ◽  
E. Borovkova
Keyword(s):  
Strain State ◽  
Residual Life ◽  
Experimental Studies ◽  
Cement Stone ◽  
Virtual Model ◽  
Structural Studies ◽  
Acoustic Sensors ◽  
Cement Pastes ◽  
The Moment ◽  
Physical And Chemical

This article describes the structural studies of a cement conglomerate, its evolution from the moment of formation to the loss of operational properties. Physical and chemical phenomena and interactions of various elements of cement stone are considered. The study of its rheology includes creating a virtual model and monitoring the formation of the structure of cement pastes by acoustic emission (AE). The results of combined experimental studies to determine the residual life of cement stone samples using AE and tensometry methods are presented. The authors created a complex for monitoring the stress-strain state of artificial conglomerates, which includes both internal and acoustic sensors.

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.

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.

scholarly journals Solutions for the disposal of industrial and rain wastewater of transport enterprises in Moscow

2018 ◽  
Vol 144 ◽  
pp. 05007 ◽  
Author(s):  
Galina Varyushina
Keyword(s):  
Industrial Wastewater ◽  
High Performance ◽  
Petroleum Products ◽  
Motor Vehicles ◽  
Management Systems ◽  
Chemical Methods ◽  
Sustainable Solutions ◽  
Fuel Tanks ◽  
Treatment Facilities ◽  
Physical And Chemical

The article gives results of the surveys water management systems, auto repair companies, bus compamies, taxis, fleets of trucks, production and technical enterprises. Studied technological processes of primary production: cleaning engines, flushing of radiators and parts of batteries, testing of fuel tanks, cleaning of parts and units, exterior washing and painting of motor vehicles. There were carried out field examinations of local industrial wastewater treatment facilities industrial wastewater and onsite construction runoff, the laboratory-production work to identify quantitative and qualitative indicators of the incoming and treated effluents, including petroleum products, suspended matter, salinity, synthetic surfactants, heavy metals etc. Proposed sustainable solutions for the improvement of the work of treatment facilities of rain sewage by mechanical and physical and chemical methods, including horizontal sand catchers, septic tanks – oil separator, a cascade of pressure filters with granular mineral over-loading and high-performance sorption materials, the effectiveness of treatment meets the requirements of water for its re-use for technical needs, and discharge to water bodies.

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 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 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 Effects of soft water attack on Portland and natural zeolite blended cements

2021 ◽  
pp. 9-9
Author(s):  
Tiana Milovic ◽  
Ognjen Rudic ◽  
Omran Furgan ◽  
Miroslava Radeka ◽  
Mirjana Malesev ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Natural Zeolite ◽  
Blended Cement ◽  
Soft Water ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Blended Cements ◽  
The Stability ◽  
Calcium Ion Leaching

The durability of concrete infrastructure is related to the properties of the applied concrete and the effects of the aggressive external environment on it. When concrete is directly exposed to soft water, the leaching of calcium ions from hardened cement or cement-based pastes occurs, causing reduction in strength and further deterioration of the concrete structure. This paper presents the experimental results of soft water attack effects on phase composition and compressive strength of blended cement pastes, when cement is replaced with 0%, 10%, 20% and 30% of natural zeolite. In order to simulate soft water attack in laboratory conditions, paste specimens were exposed to leaching in deionised water up to 180 days. The evaluation of the changes in phase composition (ettringite, portlandite, calcium silicate hydrate gel) due to calcium ion leaching was made based on X-ray diffraction analysis, Fourier transform infrared spectroscopy and paste compressive strength tests. The presence of portlandite and ettringite after 180 days of exposure to deionised water indicates that leaching did not influence the stability of the hydration products in blended cement pastes. Moreover, blended cement paste with 10% of natural zeolite had a higher compressive strength than the reference one.

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