The Effect of Fine Dispersed Slag Component on the Slag Portland Cement Properties

2020 ◽  
Vol 1011 ◽  
pp. 103-108
Author(s):  
Irina Kozlova ◽  
Olga Zemskova ◽  
Vyacheslav Semenov
Keyword(s):  
Portland Cement ◽  
Structural Characteristics ◽  
Initial Period ◽  
Cement Composite ◽  
Cement Matrix ◽  
Cement Stone ◽  
Ultrafine Grinding ◽  
Slag Component

Cement compositions based on slag Portland cement and fine dispersed slag component are considered. It has been established that the introduction of 1-3% fine slag obtained as a result of ultrafine grinding in a jet mill into the slag Portland cement composition provides an increase in the strength and structural characteristics of cement stone from the first day of hardening, which is important for slag cements. To ensure the fine dispersed slag particles’ stabilization in the cement matrix, the cement compositions were sealed with water with the addition of a plasticizer on either sulfa-naphthalene formaldehyde or polycarboxylate substrates in an amount of 0.5% of the cement composite content. In the research course it was found that in the initial stages of hardening and grade age, the strength of the samples containing a fine dispersed slag component and a sulfa-naphthalene formaldehyde-based plasticizer increased by 20%. When the cement composition is mixed with water with a polycarboxylate-based plasticizer, an increase in strength in the initial period of hardening by 60% is noted, at the vintage age - by 30%. At the same time, the porosity of the samples based on slag Portland cement with the addition of fine dispersed slag and one of the plasticizers in the initial period was reduced by 16-21%, at the vintage age - by 33-35%.

Leaching of Warm-Pressed CsZp-Cement Composite Waste Forms

1984 ◽  
Vol 44 ◽  
Author(s):  
Wei Fajun ◽  
Michael W. Grutzeck ◽  
Della M. Roy
Keyword(s):  
Portland Cement ◽  
Zirconium Phosphate ◽  
Cement Composite ◽  
Cement Matrix ◽  
Waste Forms ◽  
Different Temperatures

AbstractCesium zirconium phosphate [CsZr2 (PO4)3 or CsZP] has been mixed with various cement matrix materials, warm pressed, cured and leached at different temperatures. Although hydrated portland cement minerals can immobilize most of U, La and Nd (as proxies for transuranics) they are less effective in immobilizing Cs, Sr or Ba under ordinary conditions. Earlier published work showed favorable immobilization of Cs in CsZP-cement composite waste forms which compared rather favorably with many other waste forms with respect to Cs leachability. By using warm pressing combined with suitable admixtures rates of 28 to 60 day Cs leachability or the composites have been substantially reduced, attaining values of less than 0.20 g/m2. d.

scholarly journals MODEL AND MECHANISM OF CARBON NANOTUBE STABILIZATION WITH PLASTICIZER BASED ON POLYCARBOXYLATE

Vestnik MGSU ◽  
2017 ◽  
pp. 724-732
Author(s):  
Svetlana Vasilevna Samchenko ◽  
Olga Viktorovna Zemskova ◽  
Irina Vasilevna Kozlova
Keyword(s):  
Portland Cement ◽  
High Viscosity ◽  
Matrix Composition ◽  
Cement Matrix ◽  
Cement Stone ◽  
Modern Theory ◽  
Ultrasonic Dispersion ◽  
Cement System ◽  
Electrical Layer ◽  
The Stability

The method for adding into the cement matrix composition the carbon nanotubes (CNTs) in the form of stabilized suspensions for their even allocation in its volume is observed in this article. The aim of the article is to study the aggregative and sedimentary stability of the CNTs suspensions in the presence of the plasticizer based on polycarboxylate under the ultrasonic effect, to determine the kinetic addictions of coagulation, to describe the suspension stabilization models and mechanisms according to the modern theory and to determine the possibility of using CNTs as suspensions for portland cement modification. The object of research is Portland cement, CNts and polycarboxylate-based plasticizer. Mechanism of stabilization of the CNT water suspension with polycarboxylate based plasticizer due to fixing plasticizer functional groups on the nanoparticle surface is proposed. The non-polar part of the plasticizer provides the formation of high-viscosity streak between the CNTs particles and the dispersion medium, and the polar part provides the formation of the double electrical layer (DEL), which supports the formation of the CNT micelle. The Model of the CNT micelle is described. It is established that the ultrasonic dispersion provides the stability of the CNTs suspensions for seven days and more. It is shown that when the stabilized polycarboxylate-based plasticizers of the CNT are introduced in the form of suspensions into the cement paste composition, they are evenly distributed in the volume of the cement system. This causes the production of cement stone with enhanced exploitative properties.

scholarly journals INFLUENCE OF THE SCOPE ADDITION ON THE STRUCTURE FORMATION OF THE CEMENT STONE BY THE METHOD OF QUANTITATIVE X-RAY PHASE ANALYSIS

2019 ◽  
Vol 16 (4) ◽  
pp. 504-518
Author(s):  
I. L. Chulkova ◽  
I. A. Selivanov ◽  
V. D. Galdina
Keyword(s):  
Portland Cement ◽  
Structure Formation ◽  
Phase Analysis ◽  
Mineral Composition ◽  
Large Scale ◽  
Building Materials ◽  
Cement Matrix ◽  
Cement Stone ◽  
X Ray ◽  
Mineral Compositions

Introduction. The processes of structure formation of cement compositions and the development of effective technologies of building materials is an urgent task for building material science. The use of large-scale man-made product of pulp and paper enterprises – osprey as a fibrous filler in organic and mineral compositions is the successful decision of the problem. The paper analyzes the ways of using osprey in the building materials’ production. The aim of the research is to study the osprey influence on the processes of structure formation of cement stone by quantitative x-ray phase analysis.Materials and methods. The organic and mineral compositions were obtained on the basis of portland cement and osprey. The authors studied the compositions’ phase of osprey, portland cement and the processes of cement stone structure formation in organ and mineral compositions by quantitative x-ray phase analysis.Results. The authors determined the compositions’ phase of mineral impurities of osprey, cellulose, cement, cement stone, organic and mineral compositions and two compositions containing 25 and 75% by weight.Discussion and conclusions. The osprey application as a filler in the organic and mineral composition causes inhibition of processes of cement hydration. The presence of osprey in the hardening organic and mineral composition leads to a change in the composition and structure of the cement stone in comparison with the phase composition of the cement stone without additives. The result of these changes is a significant increase in the amount of calcite, waterite and a significant decrease in the amount of portland. The authors establish that the effective joint work of the reinforcing component of the osprey with the cement matrix is possible with a limited amount of osprey in organic and mineral compositions.

Mechanism of Cement Paste with Different Particle Sizes of Bottom Ash as Partial Replacement in Portland Cement

2017 ◽  
Vol 68 (10) ◽  
pp. 2367-2372 ◽  
Author(s):  
Ng Hooi Jun ◽  
Mirabela Georgiana Minciuna ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Tan Soo Jin ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Portland Cement ◽  
Construction Material ◽  
Bottom Ash ◽  
High Volume ◽  
Cement Composite ◽  
Pozzolanic Reaction ◽  
High Specific Surface Area ◽  
Partial Replacement ◽  
Natural Aggregates ◽  
Pozzolanic Properties

Manufacturing of Portland cement consists of high volume of natural aggregates which depleted rapidly in today construction field. New substitutable material such as bottom ash replace and target for comparable properties with hydraulic or pozzolanic properties as Portland cement. This study investigates the replacement of different sizes of bottom ash into Portland cement by reducing the content of Portland cement and examined the mechanism between bottom ash (BA) and Portland cement. A cement composite developed by 10% replacement with 1, 7, 14, and 28 days of curing and exhibited excellent mechanical strength on day 28 (34.23 MPa) with 63 mm BA. The porous structure of BA results in lower density as the fineness particles size contains high specific surface area and consume high quantity of water. The morphology, mineralogical, and ternary phase analysis showed that pozzolanic reaction of bottom ash does not alter but complements and integrates the cement hydration process which facilitate effectively the potential of bottom ash to act as construction material.

scholarly journals Development of lignocellulosic fiber reinforced cement composite panels using semi-dry technology

Cellulose ◽  
2021 ◽  
Vol 28 (6) ◽  
pp. 3631-3645
Author(s):  
K. M. Faridul Hasan ◽  
Péter György Horváth ◽  
Tibor Alpár
Keyword(s):  
Flexural Modulus ◽  
Cement Composite ◽  
Composite Panel ◽  
Bending Test ◽  
Morphological Properties ◽  
Cement Stone ◽  
Composite Panels ◽  
Internal Bonding ◽  
Dry Process ◽  
Lignocellulosic Fiber

AbstractThere is a growing interest in developing cement bonded lignocellulosic fiber (LF) composites with enhanced mechanical performances. This study assessed the possibility of developing composite panels with 12 mm thickness and around 1200 kg/m3 nominal densities from ordinary Portland cements (OPC) and mixed LFs from seven different woody plants found in Hungary. Once the mixed LFs were sieved and found fine (0–0.6 mm) and medium (0.6–0.8 mm) length fibers. The optimum ratio for LF, OPC, water glass (Na2SiO3), and cement stone was found to be 1:3.5:0.7:0.07. The semi-dry process, which is a comparatively cheaper and less labor intensive technology, was used for producing the composites. After 28 days of curing, the composite panels were characterized for mechanical, physical, thermal, and morphological properties. A scanning electron microscopy (SEM) test was conducted to observe the fiber orientation in the matrix before and after the bending test, which showed the clear presence of the fibers in the composites. The FTIR (Fourier transform infrared spectroscopy) was conducted to investigate the presence of chemical compounds of LF in the composite panels. Different physical (water absorption and thickness swelling) characteristics of the composite panels were investigated. Furthermore, mechanical properties (flexural properties and internal bonding strength) of the composite panels were also found to be satisfactory. The flexural modulus and internal bonding strengths of composite panel 2 is higher than other three boards, although the flexural strength is a little lower than composite panel 1. The thermogravimetric analysis and differential thermogravimetry also indicated better thermal stability of composite panels which could be used as potential insulation panel for buildings. Graphic abstract

Effect of W/B ratios on pozzolanic reaction of biomass ashes in Portland cement matrix

2012 ◽  
Vol 34 (1) ◽  
pp. 94-100 ◽  
Author(s):  
V. Sata ◽  
J. Tangpagasit ◽  
C. Jaturapitakkul ◽  
P. Chindaprasirt
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reaction ◽  
Cement Matrix ◽  
Biomass Ashes

Ultrafine Grinding of Limestone with Sodium Polyacrylates as Additives in Ordinary Portland Cement Mortar

2014 ◽  
Vol 37 (5) ◽  
pp. 787-794 ◽  
Author(s):  
Katja Ohenoja ◽  
Sandra Breitung-Faes ◽  
Päivö Kinnunen ◽  
Mirja Illikainen ◽  
Juha Saari ◽  
...  
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Mortar ◽  
Ultrafine Grinding

scholarly journals The calculation of building cooling under emergency conditions to ensure their heating reliability

Vestnik MGSU ◽  
2019 ◽  
pp. 496-501 ◽  
Author(s):  
Oleg D. Samarin
Keyword(s):  
Cooling Rate ◽  
Heat Supply ◽  
Structural Characteristics ◽  
Initial Period ◽  
Residential Building ◽  
Climatic Conditions ◽  
Time Interval ◽  
Basic Equations ◽  
Building Cooling ◽  
Air Exchange

Introduction. Continuation of research in the area of premise cooling rate calculation with the aim of obtaining dependencies, which are sufficiently accurate and take into account the most of the factors essential for the problem, but at the same time having an engineering form, is still relevant. The purpose of the study is the search for a dependence of the temperature in the building premises on time in the initial period after heat supply shutdown at emergency mode. Exponential nature of this dependence is considered as a scientific hypothesis. Materials and methods. The basic equations connecting the most important components of a heat flow in a cooling room under condition of the termination of heat supply from heating devices are used and analysed in the study. A numerical model of non-stationary thermal regime of the ventilated room is implemented on the base of the solution of a differential equations system of heat conduction and heat transfer on the surfaces of the room. Results. An analytical expression is obtained for the room cooling rate when the heat supply is disconnected, which has the form of an exponential function of square root of time since the accident. The cooling time before the condensation on the inner surface of the enclosure is determined by the example of a currently existing residential building under climatic conditions of Moscow, accounting the structural characteristics of the building and normalized fresh-air flow rate. Conclusions. It is shown that the building cooling in the initial period is influenced mainly by the ratio of the heat flux associated with unorganized air exchange and the heat loss to the environment through “light” enclosure. It was found that the decrease of natural air exchange in the building cooling process leads to a certain slowdown in the decrease of temperature, but it is not decisive. It is understood that the use of airtight light opening fillers, for example, in plastic casement, under normal conditions aggravating the sanitary and hygienic situation in the premises, under emergency conditions increases the available time interval for the restoration of heat supply.

scholarly journals A Study of the Potential Use of Red Mud to Obtain Compositions Based on Portland Cement

2020 ◽  
Author(s):  
Ekaterina Gerasimova ◽  
Elizaveta Gumirova
Keyword(s):  
Portland Cement ◽  
Red Mud ◽  
Waste Product ◽  
Cement Stone ◽  
Mathematical Planning ◽  
Alumina Production ◽  
Mineral Additive ◽  
Composition Properties ◽  
Planning Of Experiments ◽  
Potential Use

The paper deals with the problem of utilization of red mud which is a waste product from alumina production using the Bayer method. The principal possible use for the red mud of JSC “Bogoslovsky aluminum plant” (Sverdlovsk region) for the compositions based on Portland cement is shown. It was found that the mud introduction accelerates beginning of the cement paste setting and thickens the paste reducing its mobility. It is concluded that the introduction of red mud up to 30 % is justified in terms of strength indicators. The work is carried out using mathematical planning of experiments. Keywords: red mud, Portland cement, active mineral additive, composition, properties, bauxite, chemical composition, cement stone strength, mathematical planning of experiments

scholarly journals Influence of nanocellulose on the hydration process of Portland cement and concrete properties

2020 ◽  
Vol 17 (5) ◽  
pp. 155-160
Author(s):  
V. I. Khirkhasova ◽  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Physical And Mechanical Properties ◽  
Cement Composite ◽  
High Density ◽  
Strength Characteristics ◽  
New Method ◽  
Concrete Properties ◽  
Hardening Process ◽  
Study Results

The paper deals with modification of cement composite and concrete with nanocellulose in low and high density. The author presents the study results of the influence of nanocellulose on the cement composite hardening process, as well as the physical and mechanical properties of heavy concrete. The influence of the used additive on the rheological and strength characteristics of concrete is revealed. A new method is proposed to improve the material performance.

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