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Abstract

Both shrinkage reducing admixtures (SRA) and expansive admixture (EXP) can be used to reduce the risk of cracking in concrete. Synergistic effect of using both of those admixtures simultaneously was a was found, however little information can be found on the effects of using both EXP and SRA on the properties of mortars and concrete other than shrinkage. Therefore in this paper, effect of adding both EXP and SRA on properties of mortars outside of their effect on shrinkage is researched. Mortars with Portland cement CEM I were modified by adding EXP and SRA in amount of full dose recommended by the producer, and half of the recommended dose. Research consisted of tests of properties of fresh mortars (consistency, initial setting time, hydration heat) and hardened mortars (compressive strength and drying shrinkage). It has been found that using both SRA and EXP admixtures leads to maintaining the same setting time which can be prolonged if only SRA is used, decreased compressive strength, possibility of increased consistency. Synergistic effect on shrinkage was also confirmed.
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Authors and Affiliations

Jacek Gołaszewski
1
ORCID: ORCID
Małgorzata Gołaszewska
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Civil Engineering, ul. Akademicka 5, 44-100 Gliwice
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Abstract

At thermal junctions of aluminium alloy castings and at points where risering proves to be difficult there appear internal or external

shrinkages, which are both functionally and aesthetically inadmissible. Applying the Probat Fluss Mikro 100 agent, which is based on

nano-oxides of aluminium, results in the appearance of a large amount of fine microscopic pores, which compensate for the shrinking of

metal. Experimental tests with gravity die casting of AlSi8Cu3 and AlSi10Mg alloys have confirmed that the effect of the agent can be of

advantage in foundry practice, leading to the production of castings without local concentrations of defects and without the appearance of

shrinkages and macroscopic gas pores. Also, beneficial effect on the mechanical properties of the metal has been observed.

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Authors and Affiliations

J. Roučka
J. Hotař
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Abstract

The formation process of one of the most common casting defects, a shrinkage depression concerned to shrinkage cavity, was studied. The methodology, device and the experimental set up were developed to study the shrinkage cavity growth. The kinetics of vacuum formation in the cavity of the spherical casting of Al-Si-Mg alloy at its solidification in the sand-and-clay form was investigated. The data were analysed taking in mind the temperature variation in the centre of crystallizing casting. The causes of the shrinkage depression in castings were clarified. It was determined that atmospheric pressure leads to the retraction and curvature of metal layer on the surface of the casting with lower strength below which the shrinkage cavity is formed. To avoid such defects it was recommended to use the external or internal chills, feeders and other known technological methods. Deep shrinkage cavities inside the castings could be removed with an air flow through a thin tubular needle of austenitic steels for medical injections.
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Bibliography

[1] DSTU 9051:2020. Castings of cast iron and steel. Defects. Terms and definitions. Since 01.04.2021. Pg. 15. (in Ukrainian) http://ptima.kiev.ua/images/stories/Standart/IRONSTEEL/dstu19200-80.pdf
[2] Rowley, M.T. (2007). International Atlas of Casting Defects. American Foundry Society. ISBN: 978-0874330533.
[3] GOST 19200-80. Castings of cast iron and steel. Terms and definitions of defects. (1980). (in Russian).
[4] Atlas of foundry defects. (2004). 136 Summit avenue. Montvale, NJ 07645-1720. Institute of Foundry Casting. Technopark. Pg. 23.
[5] Reisa, A., Xub, Z., Tolb, R.V. & Netoc, R. (2012). Modelling feeding flow related shrinkage defects in aluminum castings. Journal of Manufacturing Processes. 14(1), 1-7. DOI: 10.1016/j.jmapro.2011.05.003
[6] Voronin, Y.F., Kamaev V.A. (2005). Atlas of foundry defects. Moscow: Mechanical Engineering. Pg. 327. (in Russian). https://www.twirpx.com/file/914318/
[7] Chokkalingam, B. & Mohamed Nazirudeen, S.S. (2009). Analysis of casting defect through defect diagnostic study approach. Journal of Engineering Annals of the Faculty of Engineering Hunedoara. 2, 209-212. ISSN 1584-2665
[8] Beeley, P. (2001). Foundry Technology. 719. Oxford: Butterworth Heinemann. ISBN 0750645679. https://www.academia.edu/4161769/foundry_technology_by_peter_beeley/
[9] Khrychikov, V.E., Semenov, O.D., Menyaylo, O.V., Shalevskaya, I.A., & Myanovskaya, Ya.V. (2021). Elimination of weights in artistic castings with different wall thickness (Removal of shrinkage depression in art castings with different wall thickness). Casting processes (Затвердіння сплавів). 4(146). 14-21. (in Ukrainian). https://plit-periodical.com.ua/en/arhiv/removal-shrinkage-depression-art-castings-different-wall-thickness
[10] GOST R ISO 9626-2020. (2021). Stainless steel needle pipes for the manufacture of medical devices. Requirements and test methods. Pg. 28. (in Russian).
[11] Dunphy, R.P., Akerlind, C.G. & Pellini, W.S. (1954). Solidification, feed characteristics of gray cast irons and nodular cast irons. Foundry. 82(6), 106-121.
[12] Rogelberg I.L, Beilin V.M. (1983). Alloys for thermocouples (handbook). Moscow: Metallurgy. 76-77. (in Russian) https://knizhen-pazar.net/products/books/597200-splav-dlya-termopar
[13] Leibenzon, V.O., Pilyushenko, V.L., Kondratenko, V.M., Khrychikov, V.E., Nedopyokin, F.V., Bilousov, V.V. Dmitriev, Yu.V. (2009). Hardening of metals and metal compositions. Kyiv: Scientific thought. 447. (in Ukrainian. https://nmetau.edu.ua/file/tverdinnya_metaliv_i_metalevih_kompozitsiy._pidruchnik.pdf
[14] Khrychikov, V.E., Semenov, O.D., Menyaylo, O.V. (2021). Application for the patent № a202101129. Ukraine. IPC (2021.01) B22D 27/13 (2006.01), B22D 25/00. Method of removing weights in castings with thickened parts of wall. (in Ukrainian). https://base.uipv.org/searchInvStat/showclaimdetails.php?IdClaim=336807&resId=1

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Authors and Affiliations

V. Khrychikov
1
ORCID: ORCID
O. Semenov
1
ORCID: ORCID
H. Meniailo
1
ORCID: ORCID
Y. Aftandiliants
2
ORCID: ORCID
S. Gnyloskurenko
2 3
ORCID: ORCID

  1. Ukrainian State University of Science and Technologies, Ukraine
  2. National University of Life and Environmental Sciences of Ukraine, Ukraine
  3. Physical and Technological Institute of Metals and Alloys, National Academy of Sciences of Ukraine, Ukraine
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Abstract

Since the second half of the 20th century many cities in Poland lose population and the rate is more than likely to increase in future. The determinants that have the greatest impact on the process of shrinking cities are those related to economic transformation and restructuring of the so called traditional industry and consequences of the second demographic transition. In general, it can be distinguished a few main drivers for shrinkage of cities: transformation, suburbanization, demographic change (e.g. falling birth rates, outmigration in rural depopulation areas), environmental pollution. Shrinkage is a varied phenomenon because of its multidimensional, multiscalar and multitemporal character. But the multifacted character of these processes renders their recognition and estimation difficult.

The purpose of the article is to identify the sorts of shrinking cities and to presents method of measuring this process. This paper presents the differentiation of shrinking cities process in Poland on the basic of selected empirical indicators. A detailed analysis was conducted in cities with more than 100 thousand inhabitants in the period of 2000–2017.

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Authors and Affiliations

Monika Musiał-Malago’
ORCID: ORCID
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Abstract

This paper presents a new stand for studying the linear shrinkage kinetics of foundry alloys. The stand is equipped with a laser displacement sensor. Thanks to this arrangement, the measurement is of a contactless nature. This solution allows for the elimination of errors which occur in measurements made using intermediary elements (steel rods). The supposition of the expansion (shrinkage) of the sample and the expansion of the heated rod lead to the distortion of the image of the actual dimensional changes of the studied sample. A series of studies of foundry alloys conducted using the new stand allowed a new image of shrinkage kinetics to be obtained, in particular regarding cast iron. The authors introduce in the study methodology a real-time measurement of two linked quantities; shrinkage (the displacement of the free end of the sample) and temperature in the surface layer of the sample casting. This generates not only a classic image of shrinkage (S) understood as S = f (t), but also the view S = f (T). The latter correlation, developed based on results obtained using the contactless method, provide a new, so far poorly known image of the course of shrinkage in foundry alloys, especially cast iron with graphite in the structure. The study made use of hypo- and hypereutectic cast iron in order to generate an image of the differences which occur in the kinetics of shrinkage (as well as in pre-shrinkage expansion - expansion occurs during solidification).

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Authors and Affiliations

J. Zych
ORCID: ORCID
T. Snopkiewicz
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Abstract

A comparative analysis of brasses alloys, namely lead-free CuZn (CB771) and lead containing CuZn (CB770), was conducted in this article. The results of the comparative analysis and experimental investigations aimed to provide comprehensive knowledge about the thermophysical properties and solidification characteristics of these alloys. Thermodynamic simulations using Thermo-Calc software and modifications in the chemical composition of the CB771 alloy were employed to approximate its characteristics to those of the lead containing CuZn alloy. Thermal-derivative analysis of the alloys and a technological trial were carried out to determine their solidification characteristics, fluidity, and reproducibility. The casting trials were conducted under identical conditions, and the results were compared for a comprehensive analysis. Additionally, a solidification process simulation was performed using MagmaSoft software to match the thermophysical properties. The aim of this research was to achieve maximum consistency between the simulation results and experimental investigations.
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Bibliography

[1] Zoghipour, N., Tascioglu, E., Celik, F. & Kaynak, Y. (2022) - The influence of edge radius and lead content on machining performance of brass alloys. Procedia CIRP. 112, 274-279. https://doi.org/10.1016/j.procir.2022.09.084 .
[2] Hansen, A. (2019). Bleifreier rotguss als armaturen-undinstallationswerkstoff in der trinkwasserinstallation. METALL Forschung. 73(11), 452-455.
[3] Stavroulakis, P., Toulfatzis, A., Pantazopoulos, G. & Paipetis, A. (2022). Machinable leaded and eco-friendly brass alloys for high performance manufacturing processes: a critical review. Metals. 12(2), 246, 1-31. https://doi.org/10.3390/met12020246.
[4] Schultheiss, F., Johansson, D., Bushlya, V., Zhou, J., Nilsson, K. & Ståhl, J-E. (2017). Comparative study on the machinability of lead-free brass. Journal of Cleaner Production. 149, 366-377. https://doi.org/10.1016/ j.jclepro.2017.02.098.
[5] Johansson, J., Alm, P., M’Saoubi, R., Malmberg, P., Ståhl, J-E. & Bushlya, V. (2022). On the function of lead (Pb) in machining brass alloys. Journal of Advanced Manufacturing Technology. 120, 7263-7275. https://doi.org/10.1007/s00170-022-09205-0.
[6] Acceptance of metallic materials used for products in contact with drinking water, 4MS Common Approach Part B “4MS Common Composition List” Retrieved July, 12, 2022 from http://www.umweltbundesamt.de/en/topics/water/drinking-water/distributing-drinking-water/guidelines-evaluation-criteria.
[7] Directive (EU) 2020/2184 of the European Parliament and of the Council of 16 December 2020 on the quality of water intended for human consumption, Dz.U.L 435/1 of 23.12.2020.
[8] Podrzucki, C. (1991). Cast iron. STOP. (in Polish).
[9] Cholewa, M., Suchoń, J., Kondracki, M. & Jura, Z. (2009). Method of thermal derivative gradient analysis (TDGA). Archives of Foundry Engineering. 9(4), 241-245. ISSN (1897-3310).
[10] Bruna, M. & Sladek, A. (2011). Hydrogen analysis and effect of filtration on final quality of castings from aluminium alloy AlSi7Mg0,3. Archives of Foundry Engineering. 11(1), 5-10.
[11] Ignaszak, Z. (2007). Validation problems of virtual prototyping systems used in foundry for technology optimization of ductile iron castings. Advances in Integrated Design and Manufacturing in Mechanical Engineering II, Springer, 57-79. https://doi.org/10.1007/978-1-4020-6761-7_4.
[12] Fajkiel, A., Dudek, P., Walczak, W. & Zawadzki, P. (2007). Improvement of quality of a gravity die casting made from aluminum bronze be application of numerical simulation. Archives of Foundry Engineering. 7(2), 11-14. ISSN (1897-3310).
[13] Persson, P-E., Ignaszak, Z., Fransson, H., Kropotkin, V., Andersson, R. & Kump, A. (2019). increasing precision and yield in casting production by simulation of the solidification process based on realistic material data evaluated from thermal analysis (Using the ATAS MetStar System). Archives of Foundry Engineering. 19(1), 117-126. DOI: 10.24425/afe.2019.127104.
[14] Ignaszak, Z. & Wojciechowski, J. (2020). Analysis and validation of database in computer aided design of jewellery casting. Archives of Foundry Engineering. 20(1), 9-16. DOI: 10.24425/afe.2020.131275.

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Authors and Affiliations

Grzegorz Radzioch
1 2
Dariusz Bartocha
1
ORCID: ORCID
Marcin Kondracki
1
ORCID: ORCID

  1. Department of Foundry Engineering, Silesian University of Technology, 7 Towarowa Str. 44-100 Gliwice, Poland
  2. Joint Doctoral School, Silesian University of Technology, 2A Akademicka Str. 44-100 Gliwice, Poland
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Abstract

The injection moulding conditions may change the degree of crystallinity of the plastic to some extent, which affects the mechanical properties such as tensile strength and hardness. Moreover, the cooling conditions of the moulded parts may contribute to changes in their shrinkage. The paper presents the results of determination of the melting enthalpy of a polypropylene. The melting enthalpy ∆ Hm was determined by differential scanning calorimetry. It was found, that the value of the melting enthalpy depends on the physical conditions prevailing during the sample production process, such as the temperature of the liquid material, the cooling rate of the plastic (related to the mould temperature Tm) and the flow rate of the plastic in the mould. The degree of crystallinity of the obtained samples was also determined, which, depending on the measured enthalpy of fusion, influences the degree of structural order of the polymer. Standardized test samples were also analysed in terms of transversal shrinkage and longitudinal shrinkage. The shrinkage of the injection moulded parts results from the change of physical state of plastic during its solidification in the mould.
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Authors and Affiliations

P. Palutkiewicz
1
ORCID: ORCID
A. Kalwik
1
ORCID: ORCID
T. Jaruga
1

  1. Czestochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation, 19C Armii Krajowej Av., 42- 201 Czestochowa, Poland
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Abstract

The article is an attempt to compare the impact of the use of various types of limestone as the main constituent of cement on selected mortar properties. Four different limestones were added in amount of 15, 30, 40% to CEM I 42.5 R to obtain limestone cemens. Rheological properties (yield stress, plastic viscosity) of fresh mortar, tensile and compressive mortar strength, early shrinkage, and drying shrinkage were tested. Obtained results indicate that both tensile and compressive strength decreases with the increase of the limestone content in cement. Limestone can worsen or improve workability, depending on distribution of limestone grains. The addition of limestone increases the early shrinkage, but reduces the shrinkage after 28 days. Studies show that the granulation of limestone plays an important role in determining the influence of limestone on mortar properties.

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Authors and Affiliations

J. Gołaszewski
G. Cygan
M. Gołaszewska
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Abstract

Due to the large amount of binder and low water-cement ratio, high-performance cement composites have high compressive strength and a dense hardened cement paste microstructure. External curing is insufficient, as it cannot reach the interior parts of the structure, which allows autogenous shrinkage to occur in the inside. Lack of prevention of autogenous shrinkage and high restraint causes structural microcracks around rigid components (aggregate, rebars). Consequently, this phenomenon leads to the propagation of internal microcracks to the surface and reduced concrete durability. One way to minimize autogenous shrinkage is internal curing. The use of soaked lightweight aggregate to minimize the risk of cracking is not always sufficient. Sorption and desorption kinetics of fine and coarse fly ash aggregate were tested and evaluated. The correlation between the development of linear autogenous shrinkage and the tensile stresses in the restrained ring test is assessed in this paper. A series of linear specimens, with cross-section and length custom designed to match the geometry of the concrete ring, were tested and analyzed. Determination of the maximum tensile stresses caused by the restrained autogenous shrinkage in the restrained ring test, together with the approximation of the tensile strength development of the cement composites were used to evaluate the cracking risk development versus time. The high-performance concretes and mortars produced with mineral aggregates and lightweight aggregates soaked with water were tested. The use of soaked granulated fly ash coarse lightweight aggregate in cementitious composites minimized both the autogenous shrinkage and cracking risk.
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Authors and Affiliations

Adam Zieliński
1
ORCID: ORCID
Anton K. Schindler
2
ORCID: ORCID
Maria Kaszyńska
1
ORCID: ORCID

  1. West Pomeranian University of Technology, Faculty of Civil Engineering and Environmental, al. Piastów 50a, 70-311 Szczecin, Poland
  2. Department of Civil and Environmental Engineering, Auburn University, 237 Harbert Center, Alabama 36849, Auburn, USA
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Abstract

Adetailed tie model of cracking is proposed. The model is dedicated to both semi-massive RC (reinforcement concrete) members subjected to early-age imposed strains and non-massive members in which imposed strains occur after concrete hardening. As distinct from the currently applied European guidelines, the proposed model enables an analysis of crack width changes. These are a function of progressive imposed strain, material and geometry data, but also depend on the scale of cracking which determines the strain conditions of a member. Consequently, the new model takes account of not only the factors determining the cracking development but also the member relaxation effect that results from cracking. For this reason a new definition of restraint factor is proposed, which takes into account the range of cracking of a structural member, i.e. the number and width of cracks. Parametric analyses were performed of both the changes of the degree of restraint after cracking as well as the changes of crack width depending on the adopted type of aggregate, class of concrete and the coefficient of thermal expansion of concrete. These analyses indicate the potential benefits of the application of the presented model for both a more accurate interpretation of research and economical design of engineering structures.
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Authors and Affiliations

Mariusz Zych
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Civil Engineering, St. Warszawska 24, 31-155 Cracow, Poland
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Abstract

In this investigation, the confinement effects of micro synthetic fibers on lightweight foamed concrete (LFC) were examined. The parameters evaluated were porosity, water absorption, shrinkage, compressive strength, flexural strength and tensile strength. Three densities were cast which were 600 kg/m3, 1100 kg/m3, and 1600 kg/m3. Besides, the number of layers (1 to 3 layers) of micro synthetic fibers was also being examined. Based on the result obtained, the porosity improved by 8.0% to 16.3%, 13.8% to 25.6%, and 9.3% to 24.5% for the LFC with densities of 600 kg/m3, 1100 kg/m3, and 1600 kg/m3 confined with 1 layer, 2 layers, and 3 layers of micro synthetic fibers, respectively. Besides, for the water absorption test, the enhancements were 6.9% to 15.6%, 20.0 to 27.1%, and 12.2 to 29.6% for the respective densities and number of layers of micro synthetic fibers employed, while the drying shrinkage improved by 48.5% to 76.8%, 57.4% to 72.1%, and 43.2 % to 68.2% for the respective densities and number of layers of micro synthetic fibers employed. For the strength properties, a confinement with 3 layers of micro synthetic fibers showed significant results, where enhancements of 153% (600 kg/m3), 97% (1100 kg/m3), and 102% (1600 kg/m3) were obtained for the compression strength; 372% (600 kg/m3), 258% (1100 kg/m3), and 332% (1600 kg/m3) for the bending strength; and 507% (600 kg/m3), 343% (1100 kg/m3), and 332% (1600 kg/m3) for the splitting tensile strength, respectively, compared to the control LFC.
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Authors and Affiliations

Md Azree Othuman Mydin
1
ORCID: ORCID

  1. Civil Engineering, School of Housing, Building and Planning, Universiti Sains Malaysia, 11800, Penang, Malaysia
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Abstract

Optimal parameters setting of injection moulding (IM) machine critically effects productivity, quality, and cost production of end products in manufacturing industries. Previously, trial and error method were the most common method for the production engineers to meet the optimal process injection moulding parameter setting. Inappropriate injection moulding machine parameter settings can lead to poor production and quality of a product. Therefore, this study was purposefully carried out to overcome those uncertainty. This paper presents a statistical technique on the optimization of injection moulding process parameters through central composite design (CCD). In this study, an understanding of the injection moulding process and consequently its optimization is carried out by CCD based on three parameters (melt temperature, packing pressure, and cooling time) which influence the shrinkage and tensile strength of rice husk (RH) reinforced low density polyethylene (LDPE) composites. Statistical results and analysis are used to provide better interpretation of the experiment. The models are form from analysis of variance (ANOVA) method and the model passed the tests for normality and independence assumptions.
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Authors and Affiliations

Haliza Jaya
1 2
ORCID: ORCID
Nik Noriman Zulkepli
1 2
ORCID: ORCID
Mohd Firdaus Omar
1 2
ORCID: ORCID
Shayfull Zamree Abd Rahim
1 3
ORCID: ORCID
Marcin Nabiałek
4
ORCID: ORCID
Kinga Jeż
4
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID

  1. Universiti Malaysia Perlis, Centre of Excellence Geopolymer and Green Technology (CeGeoGTech), 02600 Arau, Perlis, Malaysia
  2. Universiti Malaysia Perlis (UniMAP), Faculty of Chemical Engineering Technology, Kompleks Pengajian Jejawi 2, 02600 Arau, Perlis, Malaysia
  3. Universiti Malaysia Perlis (UniMAP), Faculty of Mechanical Engineering Technology, Kampus Alam Pauh Putra, 02600 Arau, Perlis, Malaysia
  4. Częstochowa University of Technology, Department of Physics, 42-200 Częstochowa, Poland
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Abstract

The results of investigations of defects in AME-series magnesium alloys produced by the high-pressure die-casting method are presented. The analyzed magnesium alloys contain about 5 wt% aluminum and 1-5 wt% rare earth elements introduced in the form of mischmetal. The casts were fabricated using a regular type cold-chamber high-pressure die-casting machine with a 3.2 MN locking force. The same surfaces of the casts were analyzed before and after the three-point bending test in order to determine the influence of the gas and shrinkage porosity on the deformation behavior of the alloys. The obtained results revealed that the most dangerous for the cast elements is the shrinkage porosity, especially stretched in the direction perpendicular to the that of the tensile stress action. Additionally, the influence of deformation twins arise in the dendrites of the primary α (Mg) solid solution and its interaction on the cracking process was described.
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Authors and Affiliations

Katarzyna Braszczyńska-Malik
ORCID: ORCID

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Abstract

Monitoring activities on the dynamics of water shrinkage at Lake Limboto are essential to the lake’s ecosystem’s recovery. A remote sensing technology functions to monitor the dynamics of lake inundation area; this allows one to produce a comprehensive set of spatial and temporal data. Such complex satellite dataset demands extra time, greater storage resources, and greater computing capacity. The Google Earth Engine platform emerges as the alternative to tackle such problems. The present study aims to explore the capability of Google Earth Engine in formulating spatial and temporal maps of the inundation area at Lake Limboto. A total of 345 scenes of Landsat image on the study area (available during the period of 1989–2019) were involved in generating a quick inundation area map of the lake. The whole processes (pre-processing, processing, analysing, and evaluating) were automatized by using the Google Earth Engine interface. The evaluation of mapping result accuracy indicated that the average score of F1-score and Intersection over Union (IoU) was at 0.88 and 0.91, respectively. Moreover, the mapping results of the lake’s inundation area from 1989 to 2019 showed that the inundation area tended to decrease significantly in size over time. During the period, the lake’s area also shrank from 3023.8 ha in 1989 to 1275.0 ha in 2019. All in all, the spatiotemporal information about the changes in lake area may be treated as a reference for decision-making processes of lake management in the future.
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Bibliography

ACHARYA T., SUBEDI A., LEE D. 2018. Evaluation of water indices for surface water extraction in a Landsat 8 scene of Nepal. Sensors. Vol. 18, 2580. DOI 10.3390/s18082580.
AMANI M., GHORBANIAN A., AHMADI S.A., KAKOOEI M., MOGHIMI A., MIRMAZLOUMI S.M., ..., BRISCO B. 2020. Google Earth Engine Cloud Computing Platform for remote sensing big data applications: A comprehensive review. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 13 p. 5326–5350. DOI 10.1109/JSTARS.2020.3021052.
BOLANOS S., STIFF D., BRISCO B., PIETRONIRO A. 2016. Operational surface water detection and monitoring using Radarsat 2. Remote Sensing. Vol. 8, 285. DOI 10.3390/rs8040285.
BUMA W., LEE S.-I., SEO J. 2018. Recent surface water extent of Lake Chad from multispectral sensors and GRACE. Sensors. Vol. 18, 2082. DOI 10.3390/s18072082.
CHEN Z., YANG G. 2013. Analysis of drought hazards in North China: Distribution and interpretation. Natural Hazards. Vol. 65 p. 279– 294. DOI 10.1007/s11069-012-0358-3.
CLINTON N. 2017. Otsu’s method for image segmentation [online]. [Access 28.07.2020]. Available at: https://medium.com/google-earth/otsus-method-for-image-segmentation-f5c48f405e
DINKA M.O., CHAKA D.D. 2019. Analysis of land use/land cover change in Adei watershed, Central Highlands of Ethiopia. Journal of Water and Land Development. No. 41 (IV–VI) p. 146–153. DOI 10.2478/jwld-2019-0038.
DU Y., ZHANG Y., LING F., WANG Q., LI W., LI X. 2016. Water bodies’ mapping from Sentinel-2 imagery with modified Normalized Difference Water Index at 10-m spatial resolution produced by sharpening the SWIR band. Remote Sensing. Vol. 8. Iss. 4, 354 p. 1–19. DOI 10.3390/rs8040354.
ERAKU S., AKASE N., KOEM S. 2019. Analyzing Limboto Lake inundation area using Landsat 8 OLI imagery and rainfall data. Journal of Physics: Conference Series. Vol. 1317, 012111. DOI 10.1088/1742-6596/1317/1/012111.
Google Earth Engine 2020. NDVI, mapping a function over a collection, quality mosaicking [online]. [Access 02.08.2020]. Available at: https://developers.google.com/earth-engine/tutorials/tutorial _api_06.
GORELICK N., HANCHER M., DIXON M., ILYUSHCHENKO S., THAU D., MOORE R. 2017. Google Earth Engine: Planetary-scale geospatial analysis for everyone. Remote Sensing of Environment. Vol. 202 p. 18–27. DOI 10.1016/j.rse.2017.06.031.
HAMZAH R., MATSUSHITA B., TAKEHIKO F. 2018. Long-term monitoring of lake surface area change in Indonesia from global surface water data [online]. In: 17th World Lake Conference. Ibaraki, Japan p. 600–602. [Access 02.08.2020]. Available at: https://www.pref.ibarakijp/soshiki/seikatsukankyo/kasumigauraesc/04_ken- kyu/kaigi/docments/kosyou/17/ronbun/WLC17procidings_O6 _14.pdf
HARDY A., ETTRITCH G., CROSS D.E., BUNTING P., LIYWALII F., SAKALA J., SILUMESII A., SINGINI D., SMITH M., WILLIS T., THOMAS C.J. 2019. Automatic detection of open and vegetated water bodies using Sentinel 1 to map African malaria vector mosquito breeding habitats. Remote Sensing. Vol. 11, 593. DOI 10.3390/rs11050593.
HUANG C., CHEN Y., ZHANG S., WU J. 2018. Detecting, extracting, and monitoring surface water from space using optical sensors: A review. Reviews of Geophysics. Vol. 56 p. 333–360. DOI 10.1029/2018RG000598.
JASKUŁA J., SOJKA M.. 2019. Assessing spectral indices for detecting vegetative overgrowth of reservoirs. Polish Journal of Environ- mental Studies. Vol. 28. No. 6 p. 4199–4211. DOI 10.15244/pjoes/ 98994.
JIANG H., FENG M., ZHU Y., LU N., HUANG J., XIAO T. 2014. An automated method for extracting rivers and lakes from Landsat imagery. Remote Sensing. Vol. 6. Iss. 6 p. 5067–5089. DOI 10.3390/rs6065067.
JICA 2002. The study on flood control and water management Limboto-Bolango-Bone Basin in The Republic of Indonesia [online]. Final report. Vol. 1. Summary. Japan International Cooperation Agency. [Access 02.08.2020]. Available at: https://openjicareport.jica.go.jp/pdf/11709730_01.pdf
KENDALL M.G. 1975. Rank correlation methods. 4th ed. London. Griffin. ISBN 0852641990 pp. 202.
KIMIJIMA S., SAKAKIBARA M., AMIN A.K.M.A., NAGAI M., INDRIATI A.Y. 2020. Mechanism of the rapid shrinkage of Limboto Lake in Gorontalo, Indonesia. Sustainability. Vol. 12. Iss. 22, 9598. DOI 10.3390/su12229598.
KLHK 2015. Gerakan penyelamatan danau Limboto (Germadan Limboto) [Lake rescue movement of Limboto Lake]. Gorontalo. Kementerian Lingkungan Hidup dan Kehutanan pp. 91.
KOEM S., RUSIYAH 2017. Monitoring of drought events in Gorontalo Regency. IOP Conference Series: Earth and Environmental Science. Vol. 98, 012053. DOI 10.1088/1755-1315/98/1/012053.
KOEM S., RUSIYAH 2018. Karakteristik spasiotemporal kekeringan meteorologi di Kabupaten Gorontalo tahun 1981–2016 [Spatio-temporal characteristics of meteorological drought in Gorontalo Regency in 1981–2016]. Jurnal Pengelolaan Sumberdaya Alam dan Lingkungan. Vol. 8 p. 355–364. DOI 10.29244/jpsl.8.3.355-364.
KUMAR L., MUTANGA O. 2018. Google Earth Engine applications since inception: Usage, trends, and potential. Remote Sensing. Vol. 10, p. 1509. DOI 10.3390/rs10101509.
MANN H.B. 1945. Nonparametric tests against trend. Econometrica. Vol. 13. No. 3 p. 245–259. DOI 10.2307/1907187.
MAXWELL A.E., WARNER T.A. 2020. Thematic classification accuracy assessment with inherently uncertain boundaries: An argument for Center-Weighted Accuracy Assessment Metrics. Remote Sensing. Vol. 12, 1905. DOI 10.3390/rs12121905.
MCFEETERS S.K. 1996. The use of the Normalized Difference Water Index (NDWI) in the delineation of open water features. International Journal of Remote Sensing. Vol. 17 p. 1425–1432. DOI 10.1080/01431169608948714.
NGUYEN U.N.T., PHAM L.T.H., DANG T.D. 2019. An automatic water detection approach using Landsat 8 OLI and Google Earth Engine cloud computing to map lakes and reservoirs in New Zealand. Environmental Monitoring and Assessment. Vol. 191, 235. DOI 10.1007/s10661-019-7355-x.
OKORO S.U., SCHICKHOFF U., BÖHNER J., SCHNEIDER U.A. 2016. A novel approach in monitoring land-cover change in the tropics: Oil palm cultivation in the Niger Delta, Nigeria. DIE ERDE – Journal of the Geographical Society of Berlin. Vol. 147(1) p. 40–52. DOI 10.12854/erde-147-3.
OTSU N. 1979. A threshold selection method from gray-level histograms. IEEE Transactions on Systems, Man, and Cyber- netics. Vol. 9 p. 62–66. DOI 10.1109/TSMC.1979.4310076.
PEKEL J.-F., COTTAM A., GORELICK N., BELWARD A.S. 2016. High- resolution mapping of global surface water and its long-term changes. Nature. Vol. 540 p. 418–422. DOI 10.1038/nature20584.
PUTRA S.S., HASSAN C., DJUDI, SURYATMOJO H. 2013. Reservoir saboworks solutions in Limboto Lake Sedimentations, Northern Sulawesi, Indonesia. Procedia Environmental Sciences. Vol. 17 p. 230–239. DOI 10.1016/j.proenv.2013.02.033.
REZZAG BARA C., DJIDEL M., MEDJANI F., LABAR S. 2019. Spatiotemporal evolution of land surface temperature of Lake Oubeira catch-ment, northeastern Algeria. Journal of Water and Land Development. No. 43 (X–XII) p. 151–157. DOI 10.2478/jwld-2019-0073.
ROUSE W., HAAS H., DEERING W. 1973. Monitoring vegetation systems in the great plains with ERTS. In: 3rd Earth Resources Technology Satellite-1 Symposium. NASA. Vol. 1 p. 309–317.
SEN P.K. 1968. Estimates of the regression coefficient based on Kendall’s Tau. Journal of the American Statistical Association. Vol. 63(324) p. 1379. DOI 10.2307/2285891.
STUHLER S.C., LEITERER R., JOERG P.C., WULF H., SCHAEPMAN M.E. 2016. Generating a cloud-free, homogeneous Landsat-8 mosaic of Switzerland using Google Earth Engine. DOI 10.13140/RG.2.1.2432.0880.
SUBEHI L., WIBOWO H., JUNG K. 2016. Characteristics of rainfall- discharge and water quality at Limboto Lake, Gorontalo, Indonesia. Journal of Engineering and Technological Sciences. Vol. 48 p. 288–300. DOI 10.5614/j.eng.technol.sci.2016.48.3.4.
TAMIMINIA H., SALEHI B., MAHDIANPARI M., QUACKENBUSH L., ADELI S., BRISCO B. 2020. Google Earth Engine for geo-big data applica-tions: A meta-analysis and systematic review. ISPRS Journal of Photogrammetry and Remote Sensing. Vol. 164 p. 152–170. DOI 10.1016/j.isprsjprs.2020.04.001.
TRISAKTI B. 2013. Kajian penentuan luas permukaan air danau dan sebaran vegetasi air dengan metoda penginderaan jauh [Study of the lake water surface area and aquatic vegetation distribution determination based on remote sensing method]. LIMNOTEK. Vol. 20. No. 1 p. 10–20.
UMAR I., MARSYOYO A., SETIAWAN B. 2018. Analisis Perubahan Penggunaan Lahan Sekitar Danau Limboto Di Kabupaten Gorontalo [Analysis of changes in land use around Limboto Lake in Gorontalo District]. Jurnal Tata Kota dan Daerah. Vol. 10. No. 2 p. 77–90. DOI 10.21776/ub.takoda.2018.010.02.3.
WANG C., JIA, M., CHEN N., WANG W. 2018. Long-term surface water dynamics analysis based on Landsat imagery and the Google Earth Engine platform: A case study in the Middle Yangtze River Basin. Remote Sensing. Vol. 10, 1635. DOI 10.3390/rs10101635.
WANG Y., LI Z., ZENG C., XIA G.-S., SHEN H. 2020. An urban water extraction method combining deep learning and Google Earth Engine. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 13 p. 769–782. DOI 10.1109/JSTARS.2020.2971783.
WANG Y., MA J., XIAO X., WANG X., DAI S., ZHAO B. 2019. Long-term dynamic of Poyang Lake surface water: A mapping work based on the Google Earth Engine cloud platform. Remote Sensing. Vol. 11, 313. DOI 10.3390/rs11030313.
WU G., LIU Y. 2014. Satellite-based detection of water surface variation in China’s largest freshwater lake in response to hydro-climatic drought. International Journal of Remote Sensing. Vol. 35 p. 4544–4558. DOI 10.1080/01431161.2014.916444.
YUNGINGER R., BIJAKSANA S., DAHRIN D., ZULAIKAH S., HAFIDZ A., KIRANA K., SUDARNINGSIH S., MARIYANTO M., FAJAR S. 2018. Lithogenic and anthropogenic components in surface sediments from Lake Limboto as shown by magnetic mineral characteristics, trace metals, and REE geochemistry. Geosciences. Vol. 8 p. 116. DOI 10.3390/geosciences8040116.
ZHOU G., MA Z., SATHYENDRANATH S., PLATT T., JIANG C., SUN K. 2018. Canopy reflectance modeling of aquatic vegetation for algorithm development: Global sensitivity analysis. Remote Sensing. Vol. 10. Iss. 6, 837 p. 1–22. DOI 10.3390/rs10060837.
ZOU Z., DONG J., MENARGUEZ M.A., XIAO X., QIN Y., DOUGHTY R.B., HOOKER K.V., HAMBRIGHT K.D. 2017. Continued decrease of open surface water body area in Oklahoma during 1984–2015. Science of The Total Environment. Vol. 595 p. 451–460. DOI 10.1016/j.scitotenv.2017.03.259.
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Authors and Affiliations

Rakhmat Jaya Lahay
1
ORCID: ORCID
Syahrizal Koem
1
ORCID: ORCID

  1. Universitas Negeri Gorontalo, Department of Earth Science and Technology, B.J Habibie Street, Bone Bolango, 96183, Gorontalo, Indonesia
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Abstract

Estimation and application of water retention curves in heavy soils have own specifics. The reason for these specific properties is the composition of the high clay texture. This is manifested by volume changes of soil depending on moisture. Up to 40% change in the volume compared to the saturated state was recorded in the conditions of the East Slovakian Lowland. The results described in this work are based on research work carried out in the East Slovakian Lowland and represent an analysis of selected 42 samples out of a total of 250 samples in which laboratory measurements of soil water retention curves and volume changes were performed. Selected samples represent the localities Senné and Poľany. Volumetric changes were measured in a laboratory by measuring the dimensions of soil samples. Appropriate changes in the volume of soil samples should be measured when determining moisture retention curves. Neglecting this physical effect leads to a distorted determination of the water retention curves in heavy soils. In the laboratory measurement of water retention curves points, changes in the volume of the sample were measured in the range of 0.24–43.67% depending on the soil moisture potential during drainage. In the case of neglecting the effect of shrinkage during the drainage of samples, a certain error is occurring in the calculation of the volumetric moisture. The range of this error was 1–13% of volumetric moisture.

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Authors and Affiliations

Branislav Kandra
Milan Gomboš
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Abstract

New approach using direct crack width calculations of the minimum reinforcement in tensile RC elements is presented. Verification involves checking whether the provided reinforcement ensures that the crack width that may result from the thermal-shrinkage effects does not exceed the limit value. The Eurocode provisions were enriched with addendums derived from the German national annex. Three levels of accuracy of the analysis were defined - the higher the level applied, the more significant reduction in the amount of reinforcement required can be achieved. A methodology of determining the minimum reinforcement for crack width control on the example of a RC retaining wall is presented. In the analysis the influence of residual and restraint stresses caused by hydration heat release and shrinkage was considered.

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Authors and Affiliations

M. Knauff
B. Grzeszykowski
A. Golubińska
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Abstract

Self-Compacting Concrete (SCC) has been widely used in the filling layer of high-speed railways. The quality of the filling layer directly affects the durability, comfort, and safety of the track system. In this study, shrinkage characteristics and the creep behavior of SCC were investigated by compressive creep tests and shrinkage tests. They were performed on specimens with different loading levels with a calcium sulfoaluminate-based expansive agent (UEA) and viscosity modified admixture (VMA). Furthermore, based on the scanning electron microscope (SEM) morphology of hydration products and X-ray diffraction (XRD) analysis, the influence of admixtures on microstructure and mineral phases of SCC was analyzed.The results show that when concretes were loaded with the same stress level, the main factor influencing creep of SCC was the quantity and microstructure of amorphism and hydration crystal. The XRD and SEM result showed that UEA andVMAmake the creep and shrinkage of SCC reduce obviously as the cementitious system grow many crystals in hydration products. The creep of NC was less than SCC with identical compressive strength. At the same time, the addition of UEA can improve the ability to resist drying shrinkage.
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Authors and Affiliations

H. Liu
1
ORCID: ORCID
Guangchao Duan
1
ORCID: ORCID
Jingyi Zhang
2
ORCID: ORCID

  1. Shenyang Jianzhu University, School of Transportation and Geometics Engineering, No. 25 Hunnan Zhong Road, Hunnan District, 110168 Shenyang, China
  2. Shenyang Urban Construction University, School of Civil Engineering, No.380 Bai Ta Road, Hunnan District, 110167 Shenyang, China
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Abstract

The prefabricated hollow-core slab bridge is a common bridge. In prefabricated hollow-core slab bridges, joints play an important role in connecting prefabricated slabs and ensuring the integrity of the bridge. However, as the service time of the bridge increases, conventional joints have a large number of typical diseases that affect the safety and durability of bridges. In this study, a three-dimensional finite element model of the entire construction phase is established to investigate the development difference of shrinkage and creep between joints and hollow-core slabs. The effects of vehicle load and temperature gradient on joints were analysed, the failure mechanism of joints was explored, and a novel joint was proposed. The results of a nonlinear analysis showed that the novel joint can effectively improve the mechanical performance of joints and cracks can be effectively controlled. Moreover, the novel joint solves the problem in that the conventional novel joint cannot be vibrated effectively.
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Authors and Affiliations

Yujun Cui
1
ORCID: ORCID
Xingwei Xue
1
ORCID: ORCID
Hao Yao
2
ORCID: ORCID
Xudong Hua
1
ORCID: ORCID
Yuanming Huang
1
ORCID: ORCID

  1. School of Transportation and Surveying Engineering, Shenyang Jianzhu University, Shenyang, Liaoning, China
  2. Guangzhou Communications Investment Group Co., Ltd., Guangzhou, Guangdong, China

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