The Effect of Modifications on Humidity Parameters of Cement Mortar

2016 ◽  
Vol 865 ◽  
pp. 178-182
Author(s):  
Maria Wesołowska ◽  
Anna Kaczmarek
Keyword(s):  
Moisture Transport ◽  
Mesoporous Material ◽  
Cement Mortar ◽  
Mercury Porosimetry ◽  
Capillary Rise ◽  
Complex Structure ◽  
Structure Changes ◽  
Cement Mortars ◽  
Study Results ◽  
The Impact

Current wall constructions utilize cement mortars, the properties of which have been modified with introducing lime or plasticizers. The complex structure of these mortars as well as their very large inner area results in large differences in capillary moisture transport. Macroscopic studies do not allow to accurately predict the mortar behaviour in contact with water. Capillary rise as well as drying and freezing of water are dependent on the size and the layout of pores. The biggest adsorption capacity is featured by micropores. Moisture transport takes place in mesoporous material, and moisture adsorption takes place on the surface of such materials. Macropores mainly act as a transport medium and carry moisture to mesoporous material and micropores. In terms of mesoporous material and macropores mercury porosimetry is more suitable. Mortar structure plays an important role in the moisture transport. Mortar additives, that have been introduced in the form of lime and plasticizers, modify the distribution and size of pores. Porosimetric study results concerning selected mortars have been presented in this article. The structure changes resulting from the introduction additives to mortars have been analyzed and the impact on humidity of such mortars has been defined.

Effect of the Chemical Treated Kevlar Fiber on the Behaviors of Cement Mortars

2011 ◽  
Vol 306-307 ◽  
pp. 758-761
Author(s):  
Shui Zhang ◽  
Guo Zhong Li ◽  
Hai Yan Yuan
Keyword(s):  
Compressive Strength ◽  
Fracture Surface ◽  
Flexural Strength ◽  
Chemical Treatment ◽  
Cement Mortar ◽  
Impact Resistance ◽  
Reinforcement Effect ◽  
Kevlar Fiber ◽  
Cement Mortars ◽  
The Impact

This work aims to evaluate the effect of Kevlar fibers with chemical treatment on the flexural strength, compressive strength and impact resistance of cement mortar. The experimental results exhibit that Kevlar fiber with a larger percentage can increase the flexural strength and improve the impact resistance of cement mortar, and the reinforcement effect of Kevlar fiber with chemical treatment is more obvious. The surface morphology of Kevlar fiber and the fracture surface of cement mortar reinforced with Kevlar fiber were observed by SEM, and the reinforcement mechanism of the Kevlar fiber on cement mortar was discussed.

scholarly journals Experimental investigation of frost induced damage of cement mortar

2019 ◽  
Vol 282 ◽  
pp. 02103
Author(s):  
Alicja Wieczorek ◽  
Marcin Koniorczyk ◽  
Kalina Grabowska
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Cement Mortar ◽  
Cement Matrix ◽  
Capillary Absorption ◽  
Water Absorption Coefficient ◽  
Cement Mortars ◽  
Water Saturated ◽  
The Impact

Questions connected to influence of frost degradation on microstructure and physical properties of water saturated cement mortars and their resistance to cyclic water freezing are the objectives of research. The main aim of the investigation is to analyze the ice-induced deterioration of cement mortars with different water/cement ratios (w/c=0.50 and 0.40) in a accelerated durability tests. The changes of pore size distribution and water absorption coefficient are investigated by means of mercury intrusion porosimetry and capillary absorption test. Additionally, the analysis of the impact of drying temperature (40°C, 60°C, 80°C and 105°C) on the microstructure is introduced.The performed tests enabled to estimate that the destruction of the cement matrix and the range of observed changes depend on the initial pore size distribution and their volume in the cement matrix. It is also established that the increase of transport properties is correlated with the change of pore size distribution. The obtained results allow to conclude a decrease of content of small pores (up to 150nm) and increase of larger pores for mortar with w/c=0.50. Application of superplasticizer, which resulting in reduction of water to cement ratio up to 0.40, allows to obtained resistant to 150 frost cycles cement mortar.

Income Diversification and Bank Efficiency in Vietnam

2017 ◽  
pp. 52-67
Author(s):  
Sang Nguyen Minh
Keyword(s):  
Regression Model ◽  
Commercial Banks ◽  
Banking System ◽  
Operational Efficiency ◽  
Commercial Banking ◽  
Tobit Regression ◽  
Income Diversification ◽  
Positive Effects ◽  
Study Results ◽  
The Impact

This study uses the DEA (Data Envelopment Analysis) method to estimate the technical efficiency index of 34 Vietnamese commercial banks in the period 2007-2015, and then it analyzes the impact of income diversification on the operational efficiency of Vietnamese commercial banks through a censored regression model - the Tobit regression model. Research results indicate that income diversification has positive effects on the operational efficiency of Vietnamese commercial banks in the research period. Based on study results, in this research some recommendations forpolicy are given to enhance the operational efficiency of Vietnam’s commercial banking system.

Some reflections on social structure: Theoretical and practical aspects

2020 ◽  
Vol 18 (6) ◽  
pp. 1063-1078
Author(s):  
T.N. Skorobogatova ◽  
I.Yu. Marakhovskaya
Keyword(s):  
Service Industry ◽  
External Factors ◽  
Infrastructure Development ◽  
Social Infrastructure ◽  
Social Sphere ◽  
The Social ◽  
Study Results ◽  
The Republic ◽  
Internal And External Factors ◽  
The Impact

Subject. This article discusses the role of social infrastructure in the national economy and analyzes the relationship between the notions of Infrastructure, Service Industry and Non-Productive Sphere. Objectives. The article aims to outline a methodology for development of the social infrastructure of Russia's regions. Methods. For the study, we used the methods of statistical and comparative analyses. The Republic of Crimea and Rostov Oblast's social infrastructure development was considered as a case study. Results. The article finds that the level of social infrastructure is determined by a number of internal and external factors. By analyzing and assessing such factors, it is possible to develop promising areas for the social sphere advancement. Conclusions. Assessment and analysis of internal factors largely determined by the region's characteristics, as well as a comprehensive consideration of the impact of external factors will help ensure the competitiveness of the region's economy.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

The Influence of the Ash Addition from Thermal Power Plant on the Mechanical, Thermal and Dielectric Characteristics of Mortars

2018 ◽  
Vol 69 (8) ◽  
pp. 2040-2044
Author(s):  
Georgeta Velciu ◽  
Virgil Marinescu ◽  
Adriana Moanta ◽  
Ladislau Radermacher ◽  
Adriana Mariana Bors
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Power Plant ◽  
Cement Mortar ◽  
Thermal Power ◽  
Total Content ◽  
Ash Content ◽  
Dielectric Losses ◽  
Dielectric Characteristics ◽  
Cement Mortars

The influence of fly ash adittion (90 % fraction [ 100 mm) on the cement mortar characteristics was studied. The XRD, XRF, SEM and FTIR determinations indicated that fly ash used has a hollow microstructure of microsphere and cenosphere whose total content in SiO2, Al2O3 and Fe2O3 is 88.63 % and that of CaO and MgO of 8.55 %. The mechanical, thermal and dielectric determinations made on mortar samples with content of fly ash in the 0-40 % range have highlighted fact that the mechanical strength of cement mortars is maximal at 20 %, the increase in fly ash content leads to a decrease in relative density and thermal conductivity as well as and to increased dielectric losses tgd.

The Impact of Bar Service Operation Practices on Organizational Performance in Indian Hotel Industry

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohinder C. Dhiman ◽  
Abhishek Ghai
Keyword(s):  
Organizational Performance ◽  
Hotel Industry ◽  
Demographic Variables ◽  
Study Results ◽  
Service Operation ◽  
Managerial Implications ◽  
Overall Performance ◽  
The Impact ◽  
The Relationship ◽  
Bivariate Test

The paper has a two fold purpose - examine the impact of bar service operation practices (BSOP) on organizational performance (OP) and study the relationship between organizational performance and demographic variables. Based on a survey of 362 bar managers perceptions on the impact of bar service operation practices on organizational performance were assessed by 59 practices and 6 demographic variables. Bivariate test and ANOVA were employed to test the working hypothesis in the study. Results indicated that there is a positive relationship between the bar service operation practices and organizational performance. Further, the results indicate some practical and managerial implications to improve organizational overall performance.

scholarly journals Advances of 2nd Life Applications for Lithium Ion Batteries from Electric Vehicles Based on Energy Demand

2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich
Keyword(s):  
Life Cycle ◽  
Lithium Ion Batteries ◽  
Electric Vehicles ◽  
Energy Demand ◽  
Lithium Ion ◽  
Life Cycles ◽  
Future Research ◽  
Research Areas ◽  
Study Results ◽  
The Impact

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.

scholarly journals Properties of Calcium Sulfoaluminate Cement Mortar Modified by Hydroxyethyl Methyl Celluloses with Different Degrees of Substitution

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2136
Author(s):  
Shaokang Zhang ◽  
Ru Wang ◽  
Linglin Xu ◽  
Andreas Hecker ◽  
Horst-Michael Ludwig ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Cement Mortar ◽  
Retention Rate ◽  
Methyl Cellulose ◽  
Tensile Bond Strength ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Cement Mortars

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye’elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

scholarly journals Robust Step Detection from Different Waist-Worn Sensor Positions: Implications for Clinical Studies

2020 ◽  
Vol 4 (1) ◽  
pp. 50-58
Author(s):  
Matthias  Tietsch ◽  
Amir Muaremi ◽  
Ieuan Clay ◽  
Felix Kluge ◽  
Holger Hoefling ◽  
...  
Keyword(s):  
Clinical Study ◽  
Clinical Studies ◽  
Neurological Diseases ◽  
Human Gait ◽  
Robust Solution ◽  
Step Detection ◽  
Study Protocols ◽  
Study Results ◽  
Wide Range ◽  
The Impact

Analyzing human gait with inertial sensors provides valuable insights into a wide range of health impairments, including many musculoskeletal and neurological diseases. A representative and reliable assessment of gait requires continuous monitoring over long periods and ideally takes place in the subjects’ habitual environment (real-world). An inconsistent sensor wearing position can affect gait characterization and influence clinical study results, thus clinical study protocols are typically highly proscriptive, instructing all participants to wear the sensor in a uniform manner. This restrictive approach improves data quality but reduces overall adherence. In this work, we analyze the impact of altering the sensor wearing position around the waist on sensor signal and step detection. We demonstrate that an asymmetrically worn sensor leads to additional odd-harmonic frequency components in the frequency spectrum. We propose a robust solution for step detection based on autocorrelation to overcome sensor position variation (sensitivity = 0.99, precision = 0.99). The proposed solution reduces the impact of inconsistent sensor positioning on gait characterization in clinical studies, thus providing more flexibility to protocol implementation and more freedom to participants to wear the sensor in the position most comfortable to them. This work is a first step towards truly position-agnostic gait assessment in clinical settings.

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