scholarly journals Draining cement concrete for hydrotechnical, road and airport сonstruction

Author(s):  
Igor Gameliak ◽  
◽  
Anzori Shurgaya ◽  
Yaroslav Yakimenko ◽  
Andrii Mysko ◽  
...  

The article is devoted to the selection of the composition of the cement-concrete mixture and the determination of physical and mechanical parameters of the draining cement concrete for the arrangement of the pavement of footpaths, parking lots and hydraulic structures with high drainage capacity. The object of research is the processes of composition design and ensuring the strength and capacity of draining cement concrete. The aim of the work is to select the composition and determine the physical and mechanical (compressive strength, tensile bending, deformable (modulus of elasticity), operational (abrasion), frost resistance, water permeability of draining cement concrete. Research methods - scientific and experimental. The results of the article can be used in the operation of road and airfield pavements in the culverts and foundations to improve the environmental friendliness of cities.

Author(s):  
Katarzyna CYRAN ◽  
Tomasz TOBOŁA ◽  
Paweł KAMIŃSKI

The paper presents the attempt to find a correlation between the content of impurities and mechanical parameters of rock salt from the LGOM. Research was carried out in three steps: uniaxial compressive strength tests, determination of the content of insoluble minerals (impurities), and observations under the microscope and Raman microspectroscopy. The research results reveal that the rock salt which is characterized by low content of insoluble minerals (0.13–2.11% wt.) shows no correlation between the mechanical properties and the content of impurities. However, it was found that mechanical properties depend on both the distribution of impurities in halite crystals and the presence of fluid inclusions and hydrocarbons along the crystal boundaries. Moreover, the distribution of anhydrite at the edges of halite crystals may influence an increase of rock salt strength. On the contrary, the presence of fluid inclusions and hydrocarbons along the halite crystal boundaries may reduce the rock salt strength.


2018 ◽  
Vol 67 (4) ◽  
pp. 83-94
Author(s):  
Grzegorz Rogojsz ◽  
Damian Skupski ◽  
Bartosz Januszewski

This paper presents the results of laboratory tests on the properties of cement concrete containing various types of aggregate. The purpose of the tests was to determine the effect of aggregate on compressive strength, indirect tensile strength, air pore characteristics, frost resistance and the modulus of elasticity of concrete for road surfaces. The aggregate that meets the requirements for road concrete was determined on the basis of the tests. Keywords: road concrete, frost resistance of aggregate, frost resistance of road concrete.


2020 ◽  
pp. 79-90
Author(s):  
К. Л. Пашкевич ◽  
О. В. Єжова ◽  
Т. Ф. Кротова ◽  
Н. Д. Креденець ◽  
Лю Цзянсінь ◽  
...  

To study the specifics of design-projection of clothes with finishing, considering the properties of fabrics. The system approach, as well as the methods of system-structural and morphological analysis, are used. The current collections of women`s clothes, presented by modern designers, have been analyzed; the current fashion trends in manufacturing and finishing of dress fabrics and products, made from such fabrics, have been identified; the classification of types of finishing of clothes has been presented. The frequency of occurrence of different types of finishing in the collections of world-famous designers in 2011 – 2019 has been determined. Physical and mechanical properties of samples of dress fabrics have been studied, in particular: thickness, surface density, abruption characteristics; their interconnections have been identified. The recommendations on the selection of fabrics for the creation of modern women`s dresses using different types of finishing (flat, volumetric) have been developed. The interconnections between physical and mechanical parameters of dress fabrics are identified, and the recommendations on the selection of fabrics for the creation of modern women`s dresses using the finishing based on the tectonic approach are developed. The conducted set of scientific researches on the design-projection of women`s dresses, based on the tectonic approach, and the determination of physical and mechanical parameters of dress fabrics are the basis for the development of recommendations on the selection of fabrics for the manufacturing of dresses with a variety of finishes.


2000 ◽  
Vol 6 (2) ◽  
pp. 171-176 ◽  
Author(s):  
Abdel Wahid Hago ◽  
Amer Al-Rawas ◽  
Ali S. Al-Harthi

Abstract Sarooj is an artificial pozzolan produced by burning special types of clays. It has been used extensively in Oman as a cementing material in concrete masonry construction, particularly in hydraulic structures, buildings and military installations. Sarooj is cementitious when mixed with lime and water. It is a cheap cementitious material for use in construction and restoration of historical buildings. An experimental research program was developed to determine the optimum volume proportions that can be used in concrete and mortar mixtures. Twenty five sarooj-lime mixes having different proportions of sarooj, lime, sand and water were tested. In addition, tow groups of mixes (sarooj, lime, sand, water) batched by weight and by volume, with each group contained three mixes of the same proportions, were tested to study the effect of the fineness of sarooj on the strength characteristics of the sarooj-lime mix. It was found that grinding sarooj to pass the 300 mu m sieve produced the highest compressive strength, while optimum volume proportions of sarooj, lime, sand and water for the highest compressive strength was 3:1:3:1.9.


2008 ◽  
Vol 14 (4) ◽  
pp. 263-268 ◽  
Author(s):  
Romualdas Mačiulaitis ◽  
Jurgita Malaiškienė ◽  
Asta Kičaitė

In the scientific studies the influence of burning regime or composition of formation mix on the final properties of the ceramic bricks is analysed most often. However, drying regime is also of paramount importance in the process of the high quality ceramic production. The formed ceramic samples were dried according to 8 different drying regimes while burning regime was not varied during the investigation. The dried samples were burnt for 24 hours keeping the maximum temperature 1050 °C for 3 hours. Later on these parameters were determined experimentally: density, general shrinkage, compressive strength and rate of ultrasound spread. As the statistical and regression analyses of data were performed, the empirical equations, showing how the selected stages of drying regime influence the physical and mechanical parameters of ceramics, and vice versa, how the selection of the dimensions of the stages of drying regime depends on the desired values of the ceramics properties, were derived. Santrauka Statybinės keramikos kokybę labai lemia formavimo masės komponentų ir jų kiekių bei degimo režimo parinkimas. Tačiau taip pat labai svarbus yra ir teisingas keraminio pusgaminio džiovinimo režimo parinkimas, nes netinkamas keraminių pusgaminių džiovinimo intensyvumas gali būti pagrindinė keramikos dirbinių defektų atsiradimo priežastis. Defektų keramikos bandiniuose atsiranda todėl, kad per intensyviai džiovinant bandinius pusgaminyje atsiranda vidinių įtempių, kurie dėl per greito laisvo vandens pasišalinimo viršija leistinus ir pusgaminis trūkinėja net nepradėjus degimo proceso. Todėl, norint gauti kokybiškus keraminius dirbinius, yra svarbu nustatyti, kaip parinkti džiovinimo etapų dydžiai daro įtaką galutinėms keraminės šukės fizikinių-mechaninių rodiklių reikšmėms, taip pat būtų aktualu išnagrinėti džiovinimo režimo reguliavimo galimybes praktiškai. Tikslui pasiekti buvo suformuoti vienodos sudėties keraminiai bandiniai, kurie buvo išdžiovinti pagal 8 skirtingus džiovinimo režimus ir išdegti pagal vieną pasirinktą režimą. Vėliau eksperimentiškai buvo nustatyti pasirinkti fizikiniaimechaniniai rodikliai. Atlikta statistinė ir regresinė analizė, gautos empirinės lygtys, kurias naudojant galima parinkti džiovinimo režimą pagal norimus gauti fizikinius-mechaninius rodiklius, ir, atvirkščiai, parinkus džiovinimo režimą galima prognozuoti, kokios keraminės šukės fizikinių-mechaninių rodiklių reikšmės bus gautos.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 20
Author(s):  
Andrzej Ambroziak ◽  
Elżbieta Haustein ◽  
Maciej Niedostatkiewicz

This research aimed to determine the durability and strength of an old concrete built-in arch bridge based on selected mechanical, physical, and chemical properties of the concrete. The bridge was erected in 1925 and is located in Jagodnik (northern Poland). Cylindrical specimens were taken from the side ribs connected to the top plate using a concrete core borehole diamond drill machine. The properties of the old concrete were compared with the present and previous standard requirements and guidelines. The laboratory testing program consisted of the following set of tests: measurements of the depth of carbonated zone and dry density, water absorption tests, determination of concrete compressive strength and frost resistance, determination of modulus of elasticity, measurement of the pH value, determination of water-soluble chloride salt and sulfate ion content, and X-ray diffraction analyses. Large variations in the cylindrical compressive strength (14.9 to 22.0 MPa), modulus of elasticity (17,900 to 26,483 MPa), density (2064 to 2231 kg/m3), and water absorption (3.88 to 6.58%) were observed. In addition to the experiments, a brief literature survey relating to old concrete properties was also conducted. This paper can provide scientists, engineers, and designers an experimental basis in the field of old concrete built-in bridge construction.


2015 ◽  
Vol 1122 ◽  
pp. 31-34
Author(s):  
Nikol Žižková ◽  
Patrik Bayer

The article focuses on the use of tree types of pozzolanic materials in the production of cement pastes and polymer-modified cement pastes. The determined physical-mechanical parameters of the pastes with pozzolanic materials were compared with a pure cement paste. For polymeric modification, ethylene/vinyl acetate copolymer (EVA) was used, which was added to the mortar and concrete during the preparation to improve some properties such as fracture toughness, impermeability and bond strength to various substrates.


2010 ◽  
Vol 31 (10) ◽  
pp. 4748-4754 ◽  
Author(s):  
J. Wongpa ◽  
K. Kiattikomol ◽  
C. Jaturapitakkul ◽  
P. Chindaprasirt

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6933
Author(s):  
Yurii Barabanshchikov ◽  
Hien Pham ◽  
Kseniia Usanova

This work aimed to study the effect of a microfibrillated cellulose additive on strength, elastic modulus, heat release, and shrinkage of mortar and concrete. The dosage of the additive varies from 0.4 to 4.5% by weight of the cement. The change in strength with an increase in the dosage of the additive occurred in a wave-like manner. The uneven character of the change in the results also took place in the determination of heat release and shrinkage. In general, heat release and shrinkage decreased at increasing additive dosage. The additive showed the greatest decrease in the heat release of concrete at a content of 2%. The heat release of concrete practically differed little from the exotherm of the standard at an additive content of 1 and 1.5%. The addition of microfibrillated cellulose additive in small (0.5%) and large (1.5%) amounts reduced shrinkage compared to the reference, and at an intermediate content (1%), the shrinkage was higher than in the reference specimens. In this case, the water evaporation rate from concrete increased with an increase in the additive. With an increase in the additive dosage, the modulus of elasticity decreases. Thus, the microfibrillated cellulose additive provides concrete with lower values of the modulus of elasticity, heat release, and shrinkage, and the additive is recommended for use in concretes with increased crack resistance during the hardening period. The recommended additive content is 0.5% by weight of cement. At the specified dosage, it is possible to provide the class of concrete in terms of compressive strength C35/45.


2004 ◽  
Vol 852 ◽  
Author(s):  
Antonia Moropoulou ◽  
Asterios Bakolas ◽  
Eleni Aggelakopoulou ◽  
Anastasia Odatzidou ◽  
Christos Teas ◽  
...  

ABSTRACTEight syntheses of mortars used for restoration interventions in historic masonry were produced using the traditional materials of aerial lime and artificial pozzolanic additives. The mortars were aged over a 15-month period and then tested for properties related to chemical and mechanical stabilization using the following four analytical techniques: ultrasonic velocity propagation and the mortars' dynamic modulus of elasticity (Ed), mercury intrusion porosimetry for evaluation of microstructural characteristics (percentage open porosity, bulk density, average pore radius, total cumulative volume, and specific surface area), water capillary rise tests for the determination of total cumulative volume accessible to water and capillary rise coefficients of the mortars, and conventional mechanical tests for the determination of the mortars' flexural and compressive strength. Performance is correlated to the mortars' chemical composition, microstructural characteristics (as measure by average pore radius) and mechanical characteristics as measured by dynamic modulus of elasticity (Ed) and flexural and compressive strength (Fc).


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