scholarly journals Chloride Diffusion in Concrete Modified with Polyacrylic Superabsorbent Polymer (SAP) Hydrogel—The Influence of the Water-to-Cement Ratio and SAP-Entrained Water

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4064
Author(s):  
Maciej Kalinowski ◽  
Piotr Woyciechowski
Keyword(s):  
Reference Value ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Negative Influence ◽  
Chloride Diffusion ◽  
Water Release ◽  
Dry Conditions ◽  
Saturated Form ◽  
Additional Water ◽  
The Impact

This paper examines the influence of polyacrylic superabsorbent polymers (SAP) on the properties concerning chloride diffusion in cementitious materials. The conducted study investigated the influence of SAP on chloride diffusion in concretes of the initial w/c = 0.4 (for which the changes in compressive strength due to the SAP presence were negligible). The impact on the diffusivity of concrete of several variables was analyzed: the material characteristics of SAP, additional water added to the concrete to make up for the amount of water stored in the SAP structure, and the method of SAP dosing to the mix (either in a non-saturated form or in a hydrogel form). We found that, in the case of modifying concrete with polyacrylic SAP of a median particle size in dry conditions of 330 µm and without additional water, the coefficient of chloride ion diffusion was reduced to 65% of the reference value. The negative influence (increase) of increasing w/ctot by the amount of water initially entrained by SAP on the chloride diffusivity of concrete was identified. The conducted study indicates the premise of the mechanism of the water release from SAP in cementitious composites.

Testing for the Influence of the Degree of Water Saturation of Concrete upon Chloride Diffusivity

2013 ◽  
Vol 405-408 ◽  
pp. 2639-2643
Author(s):  
Van Tuan Le ◽  
Yong Lai Zheng ◽  
Shu Xin Deng
Keyword(s):  
Diffusion Coefficient ◽  
Water Saturation ◽  
Chloride Ion ◽  
Test Method ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Ion Diffusion ◽  
Chloride Diffusivity ◽  
Water Saturated ◽  
The Impact

In order to estimate the impact of the degree of water saturation of concrete to chloride ion diffusion coefficient, the experimental setup allows to measure chloride diffusion coefficient through nonsaturated concrete specimens with controlled degree of water saturated. The different degrees of water saturation of concrete specimens were obtained, by using saturated solutions of NaCl and KCl controlling the relative humidity, then applied Rapid Cloride Permeability Test method to measure the cloride diffusion coefficient. The test results show that chloride diffusion coefficient depends strongly on the degree of water saturation of concrete. Beside, this relationship shows the non-linear relationship, in which, chloride diffusion coefficient reachs the maximum value in fully saturated concrete specimens.

scholarly journals Performance Parameter Analysis of Magnesia Based Cement Products – A Review

2021 ◽  
Vol 1197 (1) ◽  
pp. 012078
Author(s):  
J Supriya ◽  
Ashwin Raut
Keyword(s):  
Chloride Ion ◽  
Cementitious Materials ◽  
Parameter Analysis ◽  
Raw Material ◽  
Flexural Behavior ◽  
Ion Diffusion ◽  
Diverse Range ◽  
Degree Of Hydration ◽  
Strength And Durability ◽  
The Impact

Abstract Magnesium oxide (MgO) based cements finds its way active in current researches where diverse range of applications and characteristics such as production process, reactivity and physical properties are essentially focus with the perception of individual expansion objectives. In general, relativity between distinctive MgO characteristics is examined in conjunction with the impact of MgO embodiment on the resources of cementitious materials is further considered. MgO is a key to develop the construction industry thereby mechanical strength and durability performance of cement paste, adhesive and concrete composites impose of MgO needs to be explored. Subsequently, this research paper explicitly defines the investigation of MgO cement composites in terms of compressive and flexural behavior, toughness, tensile and durability performances, flexibility, water susceptibility, porosity, carbonation, chloride ion diffusion, shrinkage and degree of hydration. In this regard, to application of magnesia-based cement products is influenced by various factors such as raw material, composition, performance. The review provides a detailed information of current research available related to magnesia-based cement products based on its properties.

Theoretical Analysis of Chloride Ion Migration Tests in Cementitious Material Research

2012 ◽  
Vol 450-451 ◽  
pp. 21-25
Author(s):  
Jin Bo Yang ◽  
Reng Guang Liu
Keyword(s):  
Diffusion Coefficient ◽  
Theoretical Calculations ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Accelerated Tests ◽  
Penetration Test ◽  
Migration Test ◽  
Ion Migration

Chloride ion migration tests, or so called electrical accelerated tests, for testing chloride diffusion coefficient of cementitious materials are reviewed. The ion migration theory of electrical accelerated tests is presented. Four main representative measures, chloride penetration test, steady state migration test, unsteady state migration test and salt saturated conductivity test, are introduced and their theoretical calculations of chloride diffusion coefficient are described. Through analysis of the theoretical calculations, it could be found that all electrical accelerated tests are based on ion migration theory although different suppositions are adopted. Steady state migration test is the most suitable measure to determine chloride diffusion coefficient among the migration tests. DCIPT, DRCM and DSSCT calculated by chloride penetration test, unsteady state migration test and salt saturated conductivity test could be used to identify the resistance to chloride ion penetration of cementitious materials but are not the real diffusion coefficient.

scholarly journals The Impact of Tortuosity on Chloride Ion Diffusion in Slag-Blended Cementitious Materials

2017 ◽  
Vol 15 (8) ◽  
pp. 426-439 ◽  
Author(s):  
Akira Hatanaka ◽  
Yogarajah Elakneswaran ◽  
Kiyofumi Kurumisawa ◽  
Toyoharu Nawa
Keyword(s):  
Chloride Ion ◽  
Cementitious Materials ◽  
Ion Diffusion ◽  
The Impact ◽  
Chloride Ion Diffusion

scholarly journals Elastic Wave Monitoring of Cementitious Mixtures Including Internal Curing Mechanisms

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2463
Author(s):  
Gerlinde Lefever ◽  
Didier Snoeck ◽  
Nele De Belie ◽  
Danny Van Hemelrijck ◽  
Dimitrios G. Aggelis
Keyword(s):  
Acoustic Emission ◽  
Autogenous Shrinkage ◽  
Cementitious Materials ◽  
Internal Curing ◽  
Water Evaporation ◽  
Curing Process ◽  
Hydration Kinetics ◽  
Water Release ◽  
Additional Water ◽  
Non Destructive

The mitigation of autogenous shrinkage in cementitious materials by internal curing has been widely studied. By the inclusion of water reservoirs, in form of saturated lightweight aggregates or superabsorbent polymers, additional water is provided to the hydrating matrix. The onset of water release is of high importance and determines the efficiency of the internal curing mechanism. However, the monitoring of it poses problems as it is a process that takes place in the microstructure. Using acoustic emission (AE) sensors, the internal curing process is monitored, revealing its initiation and intensity, as well as the duration. In addition, AE is able to capture the water evaporation from saturated specimens. By ultrasonic testing, differences in the hydration kinetics are observed imposed by the different methods of internal curing. The results presented in this paper show the sensitivity of combined AE and ultrasound experiments to various fundamental mechanisms taking place inside cementitious materials and demonstrate the ability of acoustic emission to evaluate internal curing in a non-destructive and easily implementable way.

Public space of the trustworthiness of sociological knowledge: The case of electoral research

2020 ◽  
pp. 13-22
Author(s):  
OLEKSANDR STEGNII
Keyword(s):  
Public Space ◽  
Research Process ◽  
Negative Influence ◽  
Election Campaign ◽  
Sociological Research ◽  
Good Tool ◽  
Sociological Knowledge ◽  
The Public ◽  
Approval Ratings ◽  
The Impact

The paper analyses specific features of sociological data circulation in a public space during an election campaign. The basic components of this kind of space with regard to sociological research are political actors (who put themselves up for the election), voters and agents. The latter refer to professional groups whose corporate interests are directly related to the impact on the election process. Sociologists can also be seen as agents of the electoral process when experts in the field of electoral sociology are becoming intermingled with manipulators without a proper professional background and publications in this field. In a public space where an electoral race is unfolding, empirical sociological research becomes the main form of obtaining sociological knowledge, and it is primarily conducted to measure approval ratings. Electoral research serves as an example of combining the theoretical and empirical components of sociological knowledge, as well as its professional and public dimensions. Provided that sociologists meet all the professional requirements, electoral research can be used as a good tool for evaluating the trustworthiness of results reflecting the people’s expression of will. Being producers of sociological knowledge, sociologists act in two different capacities during an election campaign: as analysts and as pollsters. Therefore, it is essential that the duties and areas of responsibility for professional sociologists should be separated from those of pollsters. Another thing that needs to be noted is the negative influence that political strategists exert on the trustworthiness of survey findings which are going to be released to the public. Using the case of approval ratings as an illustration, the author analyses the most common techniques aimed at misrepresenting and distorting sociological data in the public space. Particular attention is given to the markers that can detect bogus polling companies, systemic violations during the research process and data falsification.

TO THE QUESTION OF THE IMPACT OF CLIMATE CHANGE ON THE ECOLOGICAL STATE OF ARTIFICIAL PLANTATIONS OF PITSUNDSKAYA PINE IN THE SEASIDE AREA OF GELENDZHIK

2017 ◽  
Author(s):  
Elizaveta Derevenets ◽  
Elizaveta Derevenets
Keyword(s):  
Negative Impact ◽  
Standard Technique ◽  
Negative Influence ◽  
Exhaust Gases ◽  
The Road ◽  
Industrial Enterprises ◽  
Federal Highway ◽  
On The Road ◽  
The Impact ◽  
The City

Gelendzhik is the resort town, there aren't a lot of industrial enterprises here. The main pollutant is transport. The work purpose is the assessment of a condition of the artificial landings of a pine located along the Federal highway "Don" and landings, which is nearly the sea coast. Researches were conducted to a standard technique of the General vital state (A. S. Bogolyubov). The assessment of a condition of pines was carried out during 6 years: from 2010 to 2015. For carrying out research we used 6 experimental grounds on the Markotkhsky spine and 2 control grounds within the town. We investigated 24 trees on each platform, middle age of the trees were 30 - 40 years. Results. 1. The condition of trees in the pine forests located in immediate proximity with the Federal highway "Don" (No. 1, 2, 3) is unsatisfactory. As even weak influences of the majority of atmospheric gaseous pollutants (sulphurous gas, nitrogen oxides, etc.) give effect of a necrosis and hloroz of pine needles, the condition of pines is connected with technogenic pollution. So near the Federal highway "Don" the air environment is strongly polluted by exhaust gases. Information of 2012 confirm that negative influence of the route on Markotkh's vegetation decreases at reduction of load of the route. 2. On the sites located above on a slope (No. 4,5,6) thanks to remoteness and the wind mode intensity of influence of pollutants is lower and a condition of pines the quite satisfactory. 3. Trees on the sites located near the sea (No. 7,8) are in a good shape. Small deterioration of a state is noted in very droughty years. Conclusion. Results of six years' research show that the condition of the plantings which are in close proximity with the road worsens. It is explained by increase in intensity of the movement on the road, especially during a resort season. Gelendzhik is the city with a good ecological shape, but the damage to environment is already caused. If not to take measures, we can lose a unique part of the nature in the future, recreate it will be impossible. Measures of reduction of negative impact of exhaust gases were offered. Results of researches are transferred to ecological department of the City administration of Gelendzhik.

TO THE QUESTION OF THE IMPACT OF CLIMATE CHANGE ON THE ECOLOGICAL STATE OF ARTIFICIAL PLANTATIONS OF PITSUNDSKAYA PINE IN THE SEASIDE AREA OF GELENDZHIK

2017 ◽  
Author(s):  
Elizaveta Derevenets ◽  
Elizaveta Derevenets
Keyword(s):  
Negative Impact ◽  
Standard Technique ◽  
Negative Influence ◽  
Exhaust Gases ◽  
The Road ◽  
Industrial Enterprises ◽  
Federal Highway ◽  
On The Road ◽  
The Impact ◽  
The City

Gelendzhik is the resort town, there aren't a lot of industrial enterprises here. The main pollutant is transport. The work purpose is the assessment of a condition of the artificial landings of a pine located along the Federal highway "Don" and landings, which is nearly the sea coast. Researches were conducted to a standard technique of the General vital state (A. S. Bogolyubov). The assessment of a condition of pines was carried out during 6 years: from 2010 to 2015. For carrying out research we used 6 experimental grounds on the Markotkhsky spine and 2 control grounds within the town. We investigated 24 trees on each platform, middle age of the trees were 30 - 40 years. Results. 1. The condition of trees in the pine forests located in immediate proximity with the Federal highway "Don" (No. 1, 2, 3) is unsatisfactory. As even weak influences of the majority of atmospheric gaseous pollutants (sulphurous gas, nitrogen oxides, etc.) give effect of a necrosis and hloroz of pine needles, the condition of pines is connected with technogenic pollution. So near the Federal highway "Don" the air environment is strongly polluted by exhaust gases. Information of 2012 confirm that negative influence of the route on Markotkh's vegetation decreases at reduction of load of the route. 2. On the sites located above on a slope (No. 4,5,6) thanks to remoteness and the wind mode intensity of influence of pollutants is lower and a condition of pines the quite satisfactory. 3. Trees on the sites located near the sea (No. 7,8) are in a good shape. Small deterioration of a state is noted in very droughty years. Conclusion. Results of six years' research show that the condition of the plantings which are in close proximity with the road worsens. It is explained by increase in intensity of the movement on the road, especially during a resort season. Gelendzhik is the city with a good ecological shape, but the damage to environment is already caused. If not to take measures, we can lose a unique part of the nature in the future, recreate it will be impossible. Measures of reduction of negative impact of exhaust gases were offered. Results of researches are transferred to ecological department of the City administration of Gelendzhik.

scholarly journals Experimental Study and Simulation Calculation of the Chloride Resistance of Concrete under Multiple Factors

2021 ◽  
Vol 11 (12) ◽  
pp. 5322
Author(s):  
Yang Ding ◽  
Tong-Lin Yang ◽  
Hui Liu ◽  
Zhen Han ◽  
Shuang-Xi Zhou ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Penetration Depth ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Chloride Ions ◽  
Finite Element Software ◽  
Chloride Resistance ◽  
Simulation Calculation ◽  
Marine Concrete ◽  
Resistance Performance

Cement is widely used in marine concrete, and its resistance to chloride ion corrosion has been widely considered. In this paper, based on a laboratory test, the influence of different hydrostatic pressures, coarse aggregate contents and w/c ratios on the chloride resistance performance is analyzed. Based on COMSOL finite element software, a two-dimensional cementitious materials model is established, and the simulation results are compared with the experimental results. The results show that the penetration depth of chloride ions in cement increases with the increase of the w/c ratio. Under the hydrostatic pressure of 0 MPa, when the w/c ratio is 0.35, the penetration depth of chloride ions is 7.4 mm, and the simulation result is 8.0 mm. When the w/c ratio is 0.45, the penetration depth of chloride ions is 9.3 mm, and the simulation result is 9.9 mm. When the w/c ratio is 0.55, the penetration depth of chloride ions is 12.9 mm, and the simulation result is 12.1 mm. Under different hydrostatic pressures, the penetration depth of chloride ions obviously changes, and with the increase in hydrostatic pressure, the penetration depth of chloride ions deepens. Under the w/c ratio of 0.35, when the hydrostatic pressure is 0.5 MPa, the penetration depth of chloride ions is 11.3 mm, and the simulation result is 12.1 mm. When the hydrostatic pressure is 1.0 MPa, the penetration depth of chloride ions is 16.2 mm, and the simulation result is 17.5 mm.

scholarly journals Microstructure and Durability Performance of Mortars with Volcanic Powder from Calbuco Volcano (Chile) after 4 Hardening Years

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1751
Author(s):  
Rosa María Tremiño ◽  
Teresa Real-Herraiz ◽  
Viviana Letelier ◽  
José Marcos Ortega
Keyword(s):  
Water Absorption ◽  
Thermal Analyses ◽  
Length Change ◽  
Cement Industry ◽  
Chloride Diffusion ◽  
Beneficial Effects ◽  
State Diffusion ◽  
Calbuco Volcano ◽  
Reference Specimens ◽  
The Impact

One of the most popular ways to lessen the impact of the cement industry on the environment consists of substituting clinker by additions. The service life required for real construction elements is generally long, so it would be interesting to obtain information about the effects of new additions after a hardening period of several years. Analyzed here are the effects of the incorporation of volcanic ashes, coming from Calbuco volcano’s last eruption (Chile), as clinker replacement, in the durability and pore structure of mortars, after approximately 4 hardening years (1500 days), in comparison with reference specimens without additions. The substitution percentages of clinker by volcanic powder studied were 10% and 20%. The microstructure was characterized with mercury intrusion porosimetry and impedance spectroscopy. In order to evaluate the pozzolanic activity of the volcanic powder after 1500 days, differential thermal analyses were performed. Water absorption after immersion, steady-state diffusion coefficient and length change were also studied. In accordance with the results obtained, the 10% and 20% substitution of clinker by volcanic powder from the Calbuco volcano showed beneficial effects in the mortars after 4 years, especially regarding the microstructure and chloride diffusion, without noticeable influence in their water absorption.

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