scholarly journals The possibility of shrinkage strain reduction in cements mortars

2018 ◽  
Vol 174 ◽  
pp. 02013
Author(s):  
Maciej Gruszczyński ◽  
Grzegorz Bajorek
Keyword(s):  
Cement Hydration ◽  
Shrinkage Strain ◽  
Strength Development ◽  
Action Mechanism ◽  
Chemical Admixtures ◽  
Cement Mortars ◽  
Different Types ◽  
The Subject ◽  
Polymer Dispersions ◽  
Styrene Butadiene

The subject of the paper is presentation of action mechanism and effectiveness estimation of different types of chemical admixtures that make it possible to control the course of shrinkage strains associated with cement hydration process. There are presented tests results from the research program realization in which there were used the basic types of admixtures allowing for producing mortars and concretes with reduced or compensated shrinkage. In conducted tests there were applied admixtures based on calcium oxide, multi-molecule alcohol as well as water polymer dispersions (styrene-acrylic co-polymer - SA and styrene-butadiene latex - SBR). Their influence onto the magnitude of shrinkage strain and strength development for cement mortars was analyzed.

Resistance of Polymer Dispersion Additive Modified Concrete to Light Liquids Action

2014 ◽  
Vol 941-944 ◽  
pp. 730-733 ◽  
Author(s):  
Maciej Gruszczyński
Keyword(s):  
Concrete Strength ◽  
Polymer Concrete ◽  
Material Structure ◽  
Reinforced Concrete Structures ◽  
Polymer Dispersion ◽  
Petrol Station ◽  
Concrete Properties ◽  
Different Types ◽  
The Subject ◽  
Styrene Butadiene

Numerous concrete and reinforced concrete structures (industrial floors, petrol station or manoeuvring park pavements, elements of sewage system) are subjected to danger of permanent or periodical action of petroleum liquids that often causes the considerable reduction in concrete strength as well as decrease of bond between concrete and steel, which usually results in structure damages. The subject of the paper is estimation of influence of polymer dispersion additive (styrene-acrylic co-polymer and styrene-butadiene latex) onto durability of concrete subjected to action of different types of light liquids. The influence of polymer dispersion additive was confronted with the action of silica fume usually applied for sealing the structure of concrete. In the paper there are presented tests results for different types of light liquids onto such cement-polymer concrete properties as: strength, penetration depth of light liquids into material structure.

Point and planar defects in the iron sulfide compounds Fe1-xS

1984 ◽  
Vol 42 ◽  
pp. 434-435
Author(s):  
Thao A. Nguyen
Keyword(s):  
Low Temperatures ◽  
Direct Evidence ◽  
Iron Sulfide ◽  
Planar Defects ◽  
Selective Area ◽  
Vacancy Ordering ◽  
Different Types ◽  
Lattice Images ◽  
The Subject ◽  
Beam Lattice

It is well known that the large deviations from stoichiometry in iron sulfide compounds, Fe1-xS (0≤x≤0.125), are accommodated by iron vacancies which order and form superstructures at low temperatures. Although the ordering of the iron vacancies has been well established, the modes of vacancy ordering, hence superstructures, as a function of composition and temperature are still the subject of much controversy. This investigation gives direct evidence from many-beam lattice images of Fe1-xS that the 4C superstructure transforms into the 3C superstructure (Fig. 1) rather than the MC phase as previously suggested. Also observed are an intrinsic stacking fault in the sulfur sublattice and two different types of vacancy-ordering antiphase boundaries. Evidence from selective area optical diffractograms suggests that these planar defects complicate the diffraction pattern greatly.

Geological Field Sketches and Illustrations

2019 ◽  
Author(s):  
Matthew J. Genge
Keyword(s):  
Cross Sections ◽  
Earth Science ◽  
Three Dimensional ◽  
Worked Examples ◽  
Scientific Publications ◽  
Thin Sections ◽  
Geological Features ◽  
Different Types ◽  
The Subject

Drawings, illustrations, and field sketches play an important role in Earth Science since they are used to record field observations, develop interpretations, and communicate results in reports and scientific publications. Drawing geology in the field furthermore facilitates observation and maximizes the value of fieldwork. Every geologist, whether a student, academic, professional, or amateur enthusiast, will benefit from the ability to draw geological features accurately. This book describes how and what to draw in geology. Essential drawing techniques, together with practical advice in creating high quality diagrams, are described the opening chapters. How to draw different types of geology, including faults, folds, metamorphic rocks, sedimentary rocks, igneous rocks, and fossils, are the subjects of separate chapters, and include descriptions of what are the important features to draw and describe. Different types of sketch, such as drawings of three-dimensional outcrops, landscapes, thin-sections, and hand-specimens of rocks, crystals, and minerals, are discussed. The methods used to create technical diagrams such as geological maps and cross-sections are also covered. Finally, modern techniques in the acquisition and recording of field data, including photogrammetry and aerial surveys, and digital methods of illustration, are the subject of the final chapter of the book. Throughout, worked examples of field sketches and illustrations are provided as well as descriptions of the common mistakes to be avoided.

scholarly journals Effect of C-S-H Nucleating Agent on Cement Hydration

2021 ◽  
Vol 11 (14) ◽  
pp. 6638
Author(s):  
Wenhao Zhao ◽  
Xuping Ji ◽  
Yaqing Jiang ◽  
Tinghong Pan
Keyword(s):  
Fractal Dimension ◽  
Cement Hydration ◽  
Nucleating Agent ◽  
Crystal Nucleation ◽  
Enhancement Effect ◽  
Hydration Products ◽  
Hydration Degree ◽  
Hydration Kinetics ◽  
Cement Mortars ◽  
Early Strength

This work aims to study the effect of a nucleating agent on cement hydration. Firstly, the C-S-H crystal nucleation early strength agent (CNA) is prepared. Then, the effects of CNA on cement hydration mechanism, early strength enhancement effect, C-S-H content, 28-days hydration degree and 28-days fractal dimension of hydration products are studied by hydration kinetics calculation, resistivity test, BET specific surface area test and quantitative analysis of backscattered electron (BSE) images, respectively. The results show that CNA significantly improves the hydration degree of cement mixture, which is better than triethanolamine (TEA). CNA shortens the beginning time of the induction period by 49.3 min and the end time of the cement hydration acceleration period by 105.1 min than the blank sample. CNA increases the fractal dimension of hydration products, while TEA decreases the fractal dimension. CNA significantly improves the early strength of cement mortars; the 1-day and 3-days strength of cement mortars with CNA are more than the 3-days and 7-days strength of the blank sample. These results will provide a reference for the practical application of the C-S-H nucleating agent.

Influence of the Composition of Cement Mortars Modified by Lime or Polymers on the Mechanical Properties and Microstructure of Mortars

2013 ◽  
Vol 592-593 ◽  
pp. 647-650 ◽  
Author(s):  
Małgorzata Lenart
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Polymer Composites ◽  
Adhesion Strength ◽  
Hardened Cement ◽  
Cement Mortars ◽  
Styrene Butadiene

Cement – polymer composites are nowadays widely used in repair systems not only in case of concrete or reinforced concrete constructions but also in masonry. Polymers addition for example already at 5% m.c. modifies the structure of the cement – polymer composite in a way that many of the mechanical properties such as flexural strength, tensile strength or adhesion to substrates are improved. The paper presents the results of tests such as flexural, compressive or adhesion strength to ceramic substrate of hardened cement mortars with different composition, as well as selected cement mortars modified by two polymers: polyvinyl alcohol and styrene – butadiene polymer dosed at 5 % m.c. Four types of cement mortars modified by lime (component used in historical constructions as well as in contemporary masonry mortars) are also examined for comparison.

Determination of optimal microwave curing cycle for fly ash mortars

2008 ◽  
Vol 35 (4) ◽  
pp. 349-357 ◽  
Author(s):  
İlker Bekir Topçu ◽  
Mehmet Uğur Toprak ◽  
Devrim Akdağ
Keyword(s):  
Fly Ash ◽  
Processing Parameters ◽  
Microwave Energy ◽  
Strength Prediction ◽  
Strength Development ◽  
Microwave Curing ◽  
Optimal Processing ◽  
Cement Mortars ◽  
Curing Cycle

Microwave energy can accelerate the hydration of cement, which results in the rapid strength development of concrete. In this paper, prediction of later age compressive strength of fly ash cement mortars, based on the accelerated strength of mortars cured with microwave energy, was investigated. To accelerate curing properly, optimal processing parameters of microwave curing (MC) on Portland cement mortars (CM) and fly ash cement mortars (FA) were first determined and then were applied to mortars. The possible early ages for the strength prediction were found to be at 6 and 8 h for CM and FA, respectively. The error percentages for prediction of CM were ±2.22% and 2.91% for 7 and 28 d, respectively. Error percentages for FA, on the other hand, were ±4.36% and 5.20% for 7 and 28 d, respectively.

The modification of bitumen with styrene–butadiene–styrene, ethylene vinyl acetate and varying the amount of reactive ethylene terpolymer

2017 ◽  
Vol 50 (3) ◽  
pp. 241-255 ◽  
Author(s):  
Seyfullah Keyf
Keyword(s):  
Vinyl Acetate ◽  
Softening Point ◽  
Elastic Recovery ◽  
Ethylene Vinyl Acetate ◽  
Modified Bitumen ◽  
Penetration Index ◽  
Different Types ◽  
Styrene Butadiene Styrene ◽  
Styrene Butadiene ◽  
Butadiene Styrene

In this article, 50/70 penetration grade TUPRAS bitumen was modified. Reactive elastomeric terpolymer (Elvaloy RET; DuPont Company), ethylene vinyl acetate (EVA) and styrene–butadiene–styrene (SBS) polymers were used in bitumen modification. Set hours of the tests were applied to samples taken from the obtained modified bitumen mixture. Varying amount of reactive ethylene terpolymer with weight ratios of 0.5%, 1.0%, 1.5%, 2.0% and 2.5% were introduced to the mixture of raw bitumen with 1.0% SBS and 1.0% EVA. Penetration, penetration index, softening point, ductility and elastic recovery tests were performed with these modified bitumen and raw bitumen. The samples of raw bitumen and modified bitumens of 2.0% Elvaloy RET, 1.0% SBS and 1.0% EVA were investigated by means of IR spectroscopy. The raw bitumen was modified with SBS, EVA and RET, and it was determined that penetration and ductility values were decreased while penetration index, softening point and elastic recovery were increased. The purpose of this study is to research the improving properties of 50/70 penetration grade–modified bitumen used in highways of Turkey. The most important characteristics (such as softening point, penetration and % elastic recovery) of new polymer-modified bitumen (NPMB) containing 2.5% EVA, 1% RET and 1% SBS were compared with eight different types of polymer-modified bitumens in Turkey (TPMB). NPMB provided all required parameters (softening point, penetration and % elastic recovery) for five different types of TPMBs (TPMB 70-16, TPMB 70-22, TPMB 76-16, TPMB 76-22 and TPMB 82-16).

scholarly journals On Understanding the Administrative Law Subject

2020 ◽  
Vol 12 ◽  
pp. 18-20
Author(s):  
Olga N. Ordina ◽  
Keyword(s):  
Public Administration ◽  
Legal Theory ◽  
Administrative Law ◽  
Executive Power ◽  
Legal Science ◽  
Different Types ◽  
Common Concept ◽  
The Subject ◽  
Points Of View ◽  
Definition Of

In the administrative and legal science there is a refinement, change and expansion of the subject of the dynamic branch of administrative law, aimed at eliminating the resulting lag of legal theory from the legal reality. In our view, of the three basic categories that characterize the subject of administrative law, “public administration”, “executive power” and “administrativepublic activity”, the main generalization category is the category “administrative and public activities”. The phenomenon of the subject of administrative law refracts the problems and discussions inherent in the industry as a whole. In view of the existence of different points of view on the subject of administrative law, the legal science has not yet formulated a single definition of it. There is a tendency to overcome the conflict between different types of understanding, to bring together the positions of different concepts of understanding of administrative law in order to form a “universal” concept of it, to develop its common concept.

scholarly journals Reutilizing Waste Iron Tailing Powders as Filler in Mortar to Realize Cement Reduction and Strength Enhancement

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 541
Author(s):  
Liyun Cui ◽  
Peiyuan Chen ◽  
Liang Wang ◽  
Ying Xu ◽  
Hao Wang
Keyword(s):  
Cement Hydration ◽  
Mercury Intrusion Porosimetry ◽  
Economic Cost ◽  
Strength Development ◽  
Effective Utilization ◽  
Strength Enhancement ◽  
Nucleation Effect ◽  
Practical Engineering ◽  
Internal Mechanism ◽  
Massive Accumulation

Recently, the massive accumulation of waste iron tailings powder (WITP) has resulted in significant environmental pollution. To solve this problem, this paper proposes an original mortar replacement (M) method to reuse waste solids and reduce cement consumption. In the experiment, the author employed an M method which replaces water, cement, and sand with WITP under constant water/cement and found that the strength development can be significantly improved. Specifically, a mortar with 20% WITP replacement can obtain a 30.95% improvement in strength development. To study the internal mechanism, we performed experiments such as thermogravimetric analysis (TGA), mercury intrusion porosimetry (MIP), and SEM. The results demonstrate that the nucleation effect and pozzolanic effect of WITP can help promote cement hydration, and MIP reveals that WITP can effectively optimize pore structure. In addition, 1 kg 20% WITP mortar reduced cement consumption by 20%, which saves 19.98% of the economic cost. Comprehensively, our approach achieves the effective utilization of WITP and provides a favorable reference for practical engineering.

scholarly journals Characteristics of heat ceramics of Mordovian territory: on the example of the collection of Mordovian republican S. D. Erzia Fine Art Museum

2019 ◽  
Vol 11 (2) ◽  
pp. 222-231
Author(s):  
Andrey S. Barmenkov
Keyword(s):  
Comparative Analysis ◽  
Morphological Analysis ◽  
Fine Art ◽  
Art Museum ◽  
Maximum Extension ◽  
Different Types ◽  
The Subject ◽  
Functional Purpose

Introduction. The article is devoted to the description of pottery ceramics on Mordovian territory. The purpose of the article is to analyze the development of ceramics in Mordovian region. The object of the article is a collection of ceramics of Mordovian republican S.D. Erzia Fine Art Museum, the subject – the main features of the ceramics based on the morphological analysis of its exhibits. Materials and Methods. The material of the study was the results of the research of Russian scholars on ceramics of antiquity and modernity, as well as empirical materials presented by the ceramics funds of Mordovian republican S.D. Erzia Fine Art Museum. One of the main approaches implemented in the article is a comparative analysis of the exhibits based on the color of the shard. It allows the author to systematize utensils according to their functional purpose, and also to make an assumption about the various historical stages of the emergence of different types. Results and Discussion. The article systematizes the variety of forms of ceramics, reveals their quantitative relationships, the prevailing forms, and gives the comparative analysis of the existing forms. The classification of vessels was carried out in accordance with a number of criteria: the height and thickness of the neck, the design of the corolla cut, the diameter of the mouth and the maximum extension of the trunk, which allows one to draw conclusions about the similarity of the collection’s exhibits with other Mordоvian artefacts. Conclusion. It concludes about the existence of a certain standard in the production of ceramic dishes, and on the similarity of the studied ceramics and the collections of Russian monuments. Therefore, it states the preservation of local Mordovian pottery traditions in the course of wide interactions with Russian pottery ceramics.

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