scholarly journals Evaluation of Cracking Patterns in Cement Composites—From Basics to Advances: A Review

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2490 ◽  
Author(s):  
Maciej Szeląg

The structure and the development degree of a cracking pattern has a key impact on the durability of cement composites. This literature review focuses on the four most important aspects related to the evaluation of the surface cracking patterns, i.e., the process of formation, propagation and evolution of cracks into a branched system of cracks from the point of view of the fracture mechanics; the detection techniques of the cracking patterns on the surface of cement composites, where the tools of computer image analysis are the most used; parameters which can quantify the development degree and morphology of the cracks system; and also the influence of a cracking pattern on the functional features of cement composites. The studies described so far indicate the necessity of continuous development of this research area, because the knowledge of key relationships between the cracking patterns and functional properties of a cement composite is necessary to estimate the degree of material degradation. Researchers agree that the works carried out in the field of evaluation of the cracking patterns, to a large extent, contributes to the development of non-destructive testing methods in the field of cement composites technology.

2020 ◽  
Vol 323 ◽  
pp. 01014
Author(s):  
Stanislav Seitl ◽  
Petr Miarka ◽  
Iva Rozsypalová ◽  
Katka Pokorná ◽  
Zbyněk Keršner ◽  
...  

From the volumetric point of view, aggregate is the most important ingredient in any kind of concrete. It is impossible to use raw soil instead of aggregate to produce concrete. There are numerous reasons for not using soil for concrete production on Earth, and we should not use lunar soil for concrete production on the Moon for the same reasons. Nevertheless, almost all developed lunar concrete-like composites, such as sulphur or polymeric concretes, are based on raw lunar soil. In the research programme, cement composite based on lunar aggregate simulant was tested. The mechanical fracture properties of the composite were the key point of interest. It was proven that the tested lunar concrete is characterized by stable and uniform properties. The obtained results were compared with the properties of other ordinary cement composites.


2020 ◽  
Vol 1 (1) ◽  
pp. 32-37
Author(s):  
I. Naydenova

As a research area, interior design took shape in the 20s of the last century, despite the fact that the practice of decorating living spaces dates back many hundreds of years. However, the "self-sufficiency" of design and its connection with architecture to this day is the subject of scientific discussions of urban specialists, historians, art historians, and anthropologists. The article discusses the leading artistic styles and trends that prevailed in architecture and design from the point of view of their mutual influence on each other. Time frame of the research: from the middle of XIX century to the first half of XX century. As a result of the research of foreign experience in the formation of interior design, the main stages of the movement development and its relationship with architecture in two formations were identified: activities directly dependent on architectural decisions, activities that determine the entire design process to a large extent: from the functional zoning of the premises to the features of the placement of utilities in the building. Entering the information era in art as a whole is characterized by the rejection of slogans that clearly delineate stylistic boundaries and determine the role of a designer in creating the living space. The determining factor influencing the integrity of the building’s appearance in a modern view is the harmony of the facade and the internal content, which was made possible thanks to the equal interaction of the architect and designer, starting from the first half of the 20th century.


Author(s):  
Jyoti Sharma ◽  
Lata Raj ◽  
Anil Gupta

The purpose of this study is to measure the existence of co-creation behavior between doctors and patients. The research also studies customer participation and customer citizenship behavior as the dimensions of co-creative behavior and tries to establish the relationship between co-creative behavior and satisfaction. This study uses Yi and Gong (2013) scale for collecting data regarding co-creation behavior and its dimensions which are customer participation (CP) and customer citizenship behavior (CCB). The data was collected from 204 patients who were suffering from various chronic/lifestyle diseases and getting their treatment from private clinics in Jammu city. The study uses 7-point Likert scale in the questionnaire ranging from 1 completely disagree through 7 completely agree, with a midpoint labeled 4 neither agree nor disagree. The analysis of paper reflects that co-creation behavior is prevalent among the patients and not only participation but the citizenship behavior also affects the co-creation behavior of patients. The study is conducted from patients point of view whereas doctors perspective should also be used in future research. The research area is restricted to Jammu city only. The research provides several implications-doctors can also use this scale for market segmentation and customer profiling for maximizing customer value co-creation behavior by gaining the useful information.


Author(s):  
Wei Liang ◽  
Lai-bin Zhang ◽  
Zhao-hui Wang

In China, the rarefaction-pressure wave techniques are widely used to diagnose the leakage fault for liquid pipelines. Many leaking propagating assumptions, such as stable single-phased flow hypothesis and none rarefaction wave front hypothesis, are often uncertain in the process of leak detection, which can easily result in some errors. Thus the rarefaction-pressure wave techniques should be integrated with other analytical techniques to compute a more accurate leak location. Additionally, the development trends of rarefaction-pressure wave techniques lie in three aspects. First, rarefaction-pressure wave detection techniques will be integrated with other compatible detection techniques and modern signal processing methods to solve the complex problems encountered in leak detection. Second, studies of rarefaction-pressure wave techniques have advanced to a new stage. The deductions on propagation mechanism of rarefaction-pressure wave have been successfully applied to determine leaks qualitatively. Third, analysis on rarefaction-pressure wave detection techniques will be made from a quantitative point of view. The quantitative data have been used to deduce leak amounts and location. The purpose of this paper is to present the recent achievements in the study of improved rarefaction-pressure wave detection techniques. The rarefaction-pressure wave detection methods, effects of incomplete information conditions, the improvements of rarefaction-pressure wave detection techniques with modified factors and propagation mechanisms are comprehensively investigated. The disfigurements of rarefaction-pressure wave are analyzed. The corresponding methods for resolving such problems as ill diagnostic information and weak amplitude values are put forward. Several methods for stronger small leakage detection ability, higher leakage positioning precision, lower false alarm rates are proposed. The application of rarefaction-pressure wave detection techniques to safety protection of liquid pipelines is also introduced. Finally, the prospect of rarefaction-pressure wave detection techniques is predicted.


Vestnik MGSU ◽  
2016 ◽  
pp. 72-81
Author(s):  
Roman Sergeevich Fedyuk

The paper deals with the development of composite binders for producing concrete with improved characteristics of gas, water and vapor permeability. The authors investigate the processes of composite materials formation in order of decreasing scale levels from macro to nanostructures. The criteria for optimization of the volume of dispersed additives in concrete are offered. The authors theoretically studied the technological features of the formation of hydrated cement stone structure. A positive effect of nanodispersed additives on the structure and physico-mechanical properties of cement composite materials are predicted. Thanks to its improved features, such as good ratio of strength and body density, high density and lifetime, the modified concrete may be used when solving various practical tasks of the construction branch.


2021 ◽  
Vol 923 (1) ◽  
pp. 012066
Author(s):  
Emad Fahad Nafeh Al-Bahli ◽  
Mahmoud Hadis Jassim Al-Jumaili

Abstract The research aimed to determine the impact studied factors represented by (people’s activities, government activities, natural factors) on the deterioration of natural pastures in the Governorate of Al-Muthanna the point of view of agricultural employees in the governorate. The research included all agricultural employees with a preparatory scientific qualification in agriculture and above in the governorate their number is (94) employees. A questionnaire was prepared to collect the data necessary to achieve the objectives of the research. It consisted of two parts. The first part included the factors related to the employees, which are (term of service, academic achievement, participation in extension activities, job position and work location). The second part included a measure to identify the agricultural employees’ the point of view of on the factors affecting the deterioration of natural pastures. It consists of (46) section spread over (3) field covered by the research. The results showed that government activities have the most impact on the deterioration of natural pastures, it was found a statistically significant difference in the respondents’ point of view about the influence of the studied factors according to their personal characteristics. The researchers concluded the necessity of agricultural expansion in pasture lands and industrial investments, as well as the importance of personal factors in assigning employees who can work in the development of natural pastures, and the researchers recommend activating government laws for the protection of natural pastures to prevent abuses (people’s activities, government activities) that contributed greatly to the deterioration of vegetation cover in the research area and taking into account the factors studied in the selection of workers in the development of natural pastures in the research area.


Vestnik MGSU ◽  
2020 ◽  
pp. 1523-1533
Author(s):  
Vladimir T. Erofeev ◽  
Victor V. Afonin ◽  
Tatiana F. Elchishcheva ◽  
Marina M. Zotkina ◽  
Irina V. Erofeeva

Introduction. An engineering method is proposed for assessing salt formation on the surface of cement composites exposed to adverse operating conditions. The technique is based on the histogram method used to determine the dominant brightness of the half-tone image of scanned cement composites. The criterion for ranking composites is a relative dimensionless value –– a metric obtained by comparing the brightness of a grayscale image with the brightness level of white. Materials and methods. We selected three types of compositions of composites in the amount of 21 items; each of them contains three samples –– a control sample and samples exposed to high humidity and positive temperatures for 15 and 45 days. Each composition is represented by a scanned raster image of the sample surface. The images are further subjected to digital processing using a software program written in the C++ programming language and the OpenCV technical vision library. This allows you to use the available methods and classes to develop algorithms to solve the problem in question and to convert a full-color RGB image to a grayscale image. Such images are used to analyze histograms, which determine the dominant level of brightness to determine the numerical metric for quantifying the salt formation on the surface of cement composite samples on the basis of their scanned images. Results. A description of the software algorithm, used to detect salt formation on the surface of cement composite specimens that have passed performance tests under high humidity conditions at positive temperatures, is presented. The method of ranking cement composite samples using the values of their dominant brightness relative to the brightness of control samples is shown. The comparative analysis of the study is presented in the form of numerical data and explanatory diagrams. Conclusions. Software modeling is employed to demonstrate the expediency of the methodology for the assessment of salt formation on the surface of cement composites and other building materials prone to salt formation.


Author(s):  
Genadijs Sahmenko ◽  
Sandis Aispurs ◽  
Aleksandrs Korjakins

Traditionally, sculptural and decorative elements of building facades are created from mortar mixes based on lime, gypsum or Portland cement. Generally these materials have porous and permeable structure, which determines their accelerated degradation, especially in the aggressive environment of modern cities. High performance cement composites (HPCC) have been considered for production and restoration of sculptural elements in historical buildings. For this purpose, fine-graded, multi-component and highly workable mixes were elaborated. Mix compositions were modified with micro-fillers, plasticizing and stabilizing admixtures, as well as fibers to improve material ductility and control shrinkage cracking. Basic mechanical properties and durability (such as water absorption, frost resistance) were determined and two types of HPCC were compared (>50 MPa: HPCC and >120 MPa: UHPCC). It has been confirmed that cement composite mixes are characterized by self-consolidating effect, high compressive strength, extremely high resistance versus freezing and thawing cycles and low water absorption. Surface quality was evaluated and initial water absorption (tube tests) were performed for laboratory samples and real sculptural elements after 5 years of exploitation. The results confirmed good potential for using HPCC for creating more attractive and durable architectural shapes and façade elements compared to elements made using traditional cement and lime mortar.


2020 ◽  
Vol 11 (87) ◽  
Author(s):  
Maryna Hederym ◽  
◽  
Nataliya Hlinka ◽  
◽  

The article is devoted to the study of one of the most important issues in modern linguistics – the problem of elliptical sentences, namely their definition, classification, different approaches to the study of this phenomenon and functioning in English-language scientific and technical texts. One of the tasks of scientific text is the ability to convey a large amount of new information in a sufficiently limited amount of text. It is this that leads to syntactic compression (the use of an ellipse) in such texts. Syntactic compression, as we have mentioned, is one of the characteristics of the modern scientific style. Authors of scientific texts seek to reduce the amount of text by compression, while increasing its content. Ellipse is a multidimensional phenomenon in language that allows authors to make the communication process more productive by using language savings. The ellipse has an extremely large pragmatic potential in achieving an extralinguistic effect. The use of the ellipse as a means of linguistic economy in scientific and technical texts is especially appropriate because the characteristic features of scientific and technical style are its informativeness (content), logic (strict sequence, clear connection between the main idea and details), accuracy and objectivity. It is an effective way of unloading sentence matter and exempting it from meaningfully redundant or structurally redundant components that carry repetitive information, it is based on the principle of compactification of predicative units. From a stylistic point of view, the desire to save language means leads to the emergence of new constructions that enrich the language, make speech dynamic, expressive. The article considers pragmatic and linguistic features of the ellipse, its structural and functional features. The article traces an attempt to review and structure the main theoretical approaches to the interpretation of the concept of "ellipse", the study of functions that perform elliptical structures in sentence structure and analysis of functional features of elliptical structures in English scientific and technical texts.


Author(s):  
Saifullah Saadat

This research was conducted to investigate the effects of factors (Identification of female cows, timely insemination of identified begging cows, diseases related to the reproductive system and nutrition) on the calving interval of dairy cows in Faryab province. Whereas, the long interval between two deliveries due to the identification of female cows, the increase in the number of inseminations (due to the failure of previous insemination), poor nutritional management and genital infections cause a long interval between calving to retrieval of cows. In that case, it will significantly reduce milk production and livestock income, because calving interval is one of the most important indicators of reproduction and economic characteristics of dairy cows, which is the interval between two calving intervals. Under the best of circumstances, one cow gives birth to only one calf per year. Calves born are important from both the point of view of meat production and replacement of old and low-producing cows. Identifying the effective factors and their effects on the calving interval between dairy cows and preventing the economic losses of dairy farmers due to increasing the calving interval between calves are the general purpose of this research. In this research, Andkhoy, Qurghan and other Faryab districts were randomly selected from three villages in each district and 10 owners from each village, which included three districts, 9 villages and nine livestock, respectively. The results of the present research showed that the interval between calving of dairy cows in the research area was due to the untimely identification of female cows by herders, increasing the number of inseminations due to the failure of previous inseminations of diseases related to the reproductive system and inadequate nutrition. The average time after delivery for the uterus to return to its previous state was 465 days.


Sign in / Sign up

Export Citation Format

Share Document