The influence of the binder type & aggregate nature on the electrical resistivity of conventional concrete

The creation of sustainable hydraulic concrete from the use of waste materials, such as PET bottles, whose performance is better than the conventional concrete, has been a great challenge worldwide within the construction industry. This article shows a study on the application of PET fibers resulting from the recycling of post-consumer bottles, which will help increase their physical and mechanical behavior. Two concrete mixtures were made: a control mixture (M-C), with the proportions of a conventional concrete and a second mixture, adding 0.8% of PET fibers with respect to the cement mass (PR-0.8). Tests of electrical resistivity, ultrasonic pulse velocity, compressive strength, tensile strength and flexural strength were performed at the ages of 7 and 28 days. The results showed a slight improvement in the mechanical behavior of the PR-0.8 mixture, in contrast to the M-C mixture, given that a non-sudden failure occurs; while that the tests of electrical resistivity and pulse velocity indicate that the concrete produced is of good quality and durable.

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Effect of Review elevated temperature on geo-polymer concrete – A Review

E3S Web of Conferences ◽

10.1051/e3sconf/202018401090 ◽

2020 ◽

Vol 184 ◽

pp. 01090

Author(s):

V Chandrakanth ◽

Srikanth Koniki

Keyword(s):

Elevated Temperature ◽

Elevated Temperatures ◽

Raw Materials ◽

Mineral Admixtures ◽

Polymer Concrete ◽

Alkaline Solutions ◽

High Temperature Strength ◽

Conventional Concrete ◽

Binder Type ◽

Fire Properties

The study on the effect of elevated temperature on Geo-polymer concrete (GPC) got its significance because conventional concrete start to deteriorate around 4000C. GPC gains attention as it is eco-friendly and economical, by utilizing industrial by-products. GPC also an alternate solution as the raw materials to produce cement are depleting day by day. GPC gains strength by geo-polymerization with the reactions between mineral admixtures and alkaline solutions. This paper presents the studies on general properties and advantages of GPC over conventional concrete which depend on properties of binder, type of curing etc. Current study mainly concentrates on effect of elevated temperatures and post fire properties of GPC depending upon rate of heating, duration of fire and maximum high temperature. Strength and durability recovery of fire damaged concrete is discussed.

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Physical, Mechanical and Durability Properties of Ecofriendly Ternary Concrete Made with Sugar Cane Bagasse Ash and Silica Fume

Crystals ◽

10.3390/cryst11091012 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1012

Author(s):

Laura Landa-Ruiz ◽

Aldo Landa-Gómez ◽

José M. Mendoza-Rangel ◽

Abigail Landa-Sánchez ◽

Hilda Ariza-Figueroa ◽

...

Keyword(s):

Compressive Strength ◽

Electrical Resistivity ◽

Portland Cement ◽

Physical Properties ◽

Silica Fume ◽

Sugar Cane ◽

Sugar Cane Bagasse ◽

Conventional Concrete ◽

Durability Properties ◽

Sugar Cane Bagasse Ash

In the present investigation, the physical, mechanical and durability properties of six concrete mixtures were evaluated, one of conventional concrete (CC) with 100% Portland cement (PC) and five mixtures of Ecofriendly Ternary Concrete (ETC) made with partial replacement of Portland Cement by combinations of sugar cane bagasse ash (SCBA) and silica fume (SF) at percentages of 10, 20, 30, 40 and 50%. The physical properties of slump, temperature, and unit weight were determined, as well as compressive strength, rebound number, and electrical resistivity as a durability parameter. All tests were carried out according to the ASTM and ONNCCE standards. The obtained results show that the physical properties of ETC concretes are very similar to those of conventional concrete, complying with the corresponding regulations. Compressive strength results of all ETC mixtures showed favorable performances, increasing with aging, presenting values similar to CC at 90 days and greater values at 180 days in the ETC-20 and ETC-30 mixtures. Electrical resistivity results indicated that the five ETC mixtures performed better than conventional concrete throughout the entire monitoring period, increasing in durability almost proportionally to the percentage of substitution of Portland cement by the SCBA–SF combination; the ETC mixture made with 40% replacement had the highest resistivity value, which represents the longest durability. The present electrical resistivity indicates that the durability of the five ETC concretes was greater than conventional concrete. The results show that it is feasible to use ETC, because it meets the standards of quality, mechanical resistance and durability, and offers a very significant and beneficial contribution to the environment due to the use of agro-industrial and industrial waste as partial substitutes up to 50% of CPC, which contributes to reduction in CO2 emissions due to the production of Portland cement, responsible for 8% of total emissions worldwide.

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In-situ electrical-resistivity measurements in the high-voltage electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107484 ◽

1978 ◽

Vol 36 (1) ◽

pp. 68-69

Author(s):

W. E. King

Keyword(s):

Electrical Resistivity ◽

Electron Microscope ◽

High Voltage ◽

Resistivity Measurements ◽

Voltage Electron ◽

High Voltage Electron Microscope ◽

High Voltage Electron ◽

Wide Range ◽

Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

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The stabilization of B.C.C. Cu in Cu/Nb nanolayered composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163605 ◽

1996 ◽

Vol 54 ◽

pp. 228-229

Author(s):

H. Kung ◽

A.J. Griffin ◽

Y.C. Lu ◽

K.E. Sickafus ◽

T.E. Mitchell ◽

...

Keyword(s):

Electrical Resistivity ◽

Layer Thickness ◽

Volume Fraction ◽

Ion Beam ◽

High Strength ◽

Cross Sectional ◽

Metastable Structure ◽

High Resolution Tem ◽

Potential Improvement ◽

Two Phases

Materials with compositionally modulated structures have gained much attention recently due to potential improvement in electrical, magnetic and mechanical properties. Specifically, Cu-Nb laminate systems have been extensively studied mainly due to the combination of high strength, and superior thermal and electrical conductivity that can be obtained and optimized for the different applications. The effect of layer thickness on the hardness, residual stress and electrical resistivity has been investigated. In general, increases in hardness and electrical resistivity have been observed with decreasing layer thickness. In addition, reduction in structural scale has caused the formation of a metastable structure which exhibits uniquely different properties. In this study, we report the formation of b.c.c. Cu in highly textured Cu/Nb nanolayers. A series of Cu/Nb nanolayered films, with alternating Cu and Nb layers, were prepared by dc magnetron sputtering onto Si {100} wafers. The nominal total thickness of each layered film was 1 μm. The layer thickness was varied between 1 nm and 500 nm with the volume fraction of the two phases kept constant at 50%. The deposition rates and film densities were determined through a combination of profilometry and ion beam analysis techniques. Cross-sectional transmission electron microscopy (XTEM) was used to examine the structure, phase and grain size distribution of the as-sputtered films. A JEOL 3000F high resolution TEM was used to characterize the microstructure.

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Chemical structure of diamond-like carbon thin films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017668x ◽

1990 ◽

Vol 48 (4) ◽

pp. 710-711

Author(s):

N.-H. Cho ◽

K.M. Krishnan ◽

D.B. Bogy

Keyword(s):

Electrical Resistivity ◽

Chemical Structure ◽

Diamond Like Carbon ◽

Chemical Structures ◽

Sputtering Power ◽

Data Aquisition ◽

Equilibrium Phases ◽

Electron Energy Loss ◽

Power Densities ◽

Preparation Techniques

Diamond-like carbon (DLC) films have attracted much attention due to their useful properties and applications. These properties are quite variable depending on film preparation techniques and conditions, DLC is a metastable state formed from highly non-equilibrium phases during the condensation of ionized particles. The nature of the films is therefore strongly dependent on their particular chemical structures. In this study, electron energy loss spectroscopy (EELS) was used to investigate how the chemical bonding configurations of DLC films vary as a function of sputtering power densities. The electrical resistivity of the films was determined, and related to their chemical structure.DLC films with a thickness of about 300Å were prepared at 0.1, 1.1, 2.1, and 10.0 watts/cm2, respectively, on NaCl substrates by d.c. magnetron sputtering. EEL spectra were obtained from diamond, graphite, and the films using a JEOL 200 CX electron microscope operating at 200 kV. A Gatan parallel EEL spectrometer and a Kevex data aquisition system were used to analyze the energy distribution of transmitted electrons. The electrical resistivity of the films was measured by the four point probe method.

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