定价： 345元 / 折扣价： 294 元

定价： 923元 / 折扣价： 785 元

定价： 260元 / 折扣价： 221 元 加购物车

4.1 In order to choose the proper material for producing semiconductor devices, knowledge of material properties such as resistivity, Hall coefficient, and Hall mobility is useful. Under certain conditions, as outlined in the Appendix, other useful quantities for materials specification, including the charge carrier density and the drift mobility, can be inferred.1.1 These test methods cover two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens. These test methods differ most substantially in their test specimen requirements.1.1.1 Test Method A, van der Pauw (1) 2—This test method requires a singly connected test specimen (without any isolated holes), homogeneous in thickness, but of arbitrary shape. The contacts must be sufficiently small and located at the periphery of the specimen. The measurement is most easily interpreted for an isotropic semiconductor whose conduction is dominated by a single type of carrier.1.1.2 Test Method B, Parallelepiped or Bridge-Type—This test method requires a specimen homogeneous in thickness and of specified shape. Contact requirements are specified for both the parallelepiped and bridge geometries. These test specimen geometries are desirable for anisotropic semiconductors for which the measured parameters depend on the direction of current flow. The test method is also most easily interpreted when conduction is dominated by a single type of carrier.1.2 These test methods do not provide procedures for shaping, cleaning, or contacting specimens; however, a procedure for verifying contact quality is given.NOTE 1: Practice F418 covers the preparation of gallium arsenide phosphide specimens.1.3 The method in Practice F418 does not provide an interpretation of the results in terms of basic semiconductor properties (for example, majority and minority carrier mobilities and densities). Some general guidance, applicable to certain semiconductors and temperature ranges, is provided in the Appendix. For the most part, however, the interpretation is left to the user.1.4 Interlaboratory tests of  these test methods (Section 19) have been conducted only over a limited range of resistivities and for the semiconductors, germanium, silicon, and gallium arsenide. However, the method is applicable to other semiconductors provided suitable specimen preparation and contacting procedures are known. The resistivity range over which the method is applicable is limited by the test specimen geometry and instrumentation sensitivity.1.5 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only. (See also 3.1.4.)1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 0元 / 折扣价： 0 元

5.1 The ER of a battery separator is a standard measurement used by separator and battery manufacturers for quality control purposes and separator selection.5.2 Separator ER and the separator's interaction with the electrolyte, that is resistance to wetting or flow, will contribute to the internal resistance of the battery and this has the potential to limit the electrical output of a battery. The ER determination is a tool for battery manufacturers to use in design, material selection, and performance specifications.5.3 The change in the bath electrical resistance imparted by a separator is affected by the porosity, thickness, and tortuousity of the pore structure of the separator, the wettability of the separator to the electrolyte, and the temperature and concentration of the electrolyte.5.4 Incomplete wetting or saturation of the pore structure limits the lowest ER value obtainable from a separator structure. Separators are pretreated to assure that the specimen being tested has been adequately wetted out. A separator that is not fully wetted out (saturated) will give a higher ER.5.5 This test method is intended to give a rapid and repeatable measurement that approximates the change in ER that could happen when the separator is used in a battery.1.1 This test method covers the pretreatment, test conditions, apparatus, and procedure to determine the ionic resistivity, commonly referred to in the battery industry as electrical resistance (ER) of an alkaline battery separator immersed in an electrolyte of 40 % potassium hydroxide (KOH).1.2 The values stated in SI units are to be regarded as the standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

4.1 The electrical behavior of semiconducting extruded shielding materials is important for a variety of reasons, such as safety, static charges, and current transmission. This test method is useful in predicting the behavior of such semiconducting compounds. Also see Test Method D4496.1.1 This test method covers the procedure for determining the volume resistivity, measured longitudinally, of extruded crosslinked and thermoplastic semiconducting, conductor and insulation shields for wire and cable.1.2 In common practice the conductor shield is often referred to as the strand shield.1.3 Technically, this test method is the measurement of a resistance between two electrodes on a single surface and modifying that value using dimensions of the specimen geometry to calculate a resistivity. However, the geometry of the specimen is such as to support the assumption of a current path primarily throughout the volume of the material between the electrodes, thus justifying the use of the term “longitudinal volume resistivity.” (See 3.1.2.1.)1.4 Whenever two sets of values are presented, in different units, the values in the first set are the standard, while those in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see 7.1.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 The resistivity of the surrounding soil environment is a factor in the corrosion of underground structures. High resistivity soils are generally not as corrosive as low resistivity soils. The resistivity of the soil is one of many factors that influence the service life of a buried structure. Soil resistivity may affect the material selection and the location of a structure.55.2 Soil resistivity is of particular importance and interest in the corrosion process because it is basic in the analysis of corrosion problems and the design of corrective measures.5.3 The test method is focused to provide an accurate, expeditious measurement of soil resistivity to assist in the determination of a soil’s corrosive nature. Test Method G57 emphasizes an in situ measurement commonly utilized in the design of a buried structures’ corrosion control (cathodic protection systems’ ground bed design, and so forth), but also includes information and procedures on a four-pin soil box method. The two-electrode soil box method is an accurate and more expeditious method than the four-pin soil box and often complements the four-pin, in situ soil resistivity method.5.4 The saturated soil resistivity determined by this test method does not necessarily indicate the minimum soil resistivity.1.1 This test method covers the equipment and procedures for the measurement of soil resistivity, for soil samples removed from the ground, for use in the assessment and control of corrosion of buried structures.1.2 Procedures allow for this test method to be used in the field or in the laboratory.1.3 The test method procedures are for the resistivity measurement of soil samples in the saturated condition and in the as-received condition.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Soil resistivity values are reported in ohm-centimeter.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and to determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 The electrical resistivity of anode and cathode carbon material is important for efficient aluminum cell operation. It is a quality parameter that determines the suitability of an anode/cathode for operation in an aluminum cell.5.2 The electrical resistivity may be selected as a requirement in a customer specification.1.1 This test method covers the determination of the electrical resistivity at room temperature of solid cylindrical specimens cored from commercial sized carbon anodes and cathodes. This test method also applies to samples from carbon blocks prepared in a laboratory.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitation prior to use. For specific warning information, see .

定价： 515元 / 折扣价： 438 元 加购物车

4.1 The electrical behavior of rubber products used in particular applications is important for a variety of reasons such as safety, static changes, current transmission, etc. This test method is useful in predicting the behavior of such rubber products.1.1 This test method covers the determination of volume resistivity of rubbers used in electrically conductive and antistatic products.1.2 This test method assumes that the surface conductivity is negligible compared with the conductivity through the specimen.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Accurate measurement of the volume resistivity of conductive adhesives is important, particularly with respect to applications in electronic packaging techniques. This method measures the resistance of conductive adhesives used in thin films as part of a bonded assembly. This does not imply that the measured results are applicable to different configurations with different metals. This method may be used for acceptance testing and for screening materials.1.1 This test method covers the determination of the volume resistivity of resin-based conductive adhesives in the cured condition. The test is made on a thin adhesive layer as prepared in a bonded specimen. This test method is used for conductive adhesives that are cured either at room temperature or at elevated temperatures.1.2 The values stated in either SI or other units shall be regarded separately as standard. SI equivalents to screw threads are shown in the figures.1.3 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

4.1 These test methods are applicable for such purposes as impurity detection and, in some cases, the quantitative measurement of ionic constituents dissolved in waters. These include dissolved electrolytes in natural and treated waters, such as boiler water, boiler feedwater, cooling water, and saline and brackish water.4.1.1 Their concentration may range from trace levels in pure waters (2)4 to significant levels in condensed steam (see Test Methods D2186 and D4519, and Ref (3)), or pure salt solutions.4.1.2 Where the principal interest in the use of conductivity methods is to determine steam purity, see Ref (4). These test methods may also be used for checking the correctness of water analyses (5).1.1 These test methods cover the determination of the electrical conductivity and resistivity of water. The following test methods are included:  Range SectionsTest Method A—Field and Routine Laboratory 10 to 200 000 12 to 18 Measurement of Static (Non-Flowing) Samples  μS/cm  Test Method B—Continuous In-Line Measure 5 to 200 000 19 to 23 ment  μS/cm  1.2 These test methods have been tested in reagent water. It is the user's responsibility to ensure the validity of these test methods for waters of untested matrices.1.3 For measurements below the range of these test methods, refer to Test Method D5391.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Concepts—The resistivity technique is used to measure the resistivity of subsurface materials. Although the resistivity of materials can be a good indicator of the type of subsurface material present, it is not a unique indicator. While the resistivity method is used to measure the resistivity of earth materials, it is the interpreter who, based on knowledge of local geologic conditions and other data, must interpret resistivity data and arrive at a reasonable geologic and hydrologic interpretation. 5.2 Parameter Being Measured and Representative Values:  5.2.1 Table 1 shows some general trends for resistivity values. Fig. 2 shows ranges in resistivity values for subsurface materials. 5.6.2 Schlumberger Array—The Schlumberger array consists of unequally spaced in-line electrodes (Fig. 3), where AB > 5 MN. The formula for calculating apparent resistivity from a Schlumberger measurement is: where: AB   =   distance between current electrodes, and MN   =   distance between potential electrodes. 5.6.3 Dipole-Dipole Array—The dipole-dipole array consists of a pair of closely spaced current electrodes and a pair of closely spaced potential electrodes (Fig. 3). The formula for calculating apparent resistivity from a dipole-dipole measurement is: where: na   =   distance between innermost electrodes measured as a number (n) of a-spacings, and a   =   distance between the current electrodes and also the potential electrodes. 5.6.4 Comparison of the Arrays:  5.6.4.1 Schlumberger Arrays:  (1) Schlumberger arrays are less susceptible to contact problems and the influence of nearby geologic conditions that may affect readings. The method provides a means to recognize the effects of lateral variations and to partially correct for them. (2) Schlumberger arrays are slightly faster in field operations since only the current electrodes must be moved between readings. 5.6.4.2 Wenner Arrays:  (1) The Wenner array provides a higher signal to noise ratio than other arrays because its potential electrodes are always farther apart and located between the current electrodes. As a result, the Wenner array measures a larger voltage for a given current than is measured with other arrays. (2) This array is good in high-noise environments such as urban areas. (3) This array requires less current for a given depth capability. This translates into less severe instrumentation requirements for a given depth capability. 5.6.4.3 Dipole-Dipole Arrays:  (1) Relatively short cable lengths are required to explore large depths. (2) Short cable lengths reduce current leakage. (3) More detailed information on the direction of dip of electrical horizons is obtainable. 5.6.5 Other Arrays—There are several other arrays: Lee-partitioning array (Zohdy et al (2)), square array (Lane et al (11)), gradient array (Ward (2)) and pole-dipole (Ward (5)) and automated data acquisition and imaging systems that are not discussed in this guideline. 5.7 Sounding (Depth) Measurements—Sounding measurements are one of the most widespread uses for the resistivity technique. Soundings provide a means of measuring changes of electrical resistivity with depth at a single location. Several measurements are made with increasing electrode spacings. As the spacing of the electrodes is increased, there is an increase in the depth and volume of material measured (Fig. 4). The center point of the array remains fixed as the electrical spacing is increased. FIG. 4 Increased Electrode Spacing Samples Greater Depth and Volume of Earth (from Benson et al, (8)) 5.7.1 Sounding measurements result in a series of apparent electrical resistivity values at various electrode spacings. These apparent resistivity values are plotted against electrode spacing using a log-log scale (Fig. 5) and are interpreted using inversion techniques to derive true resistivity and thickness of subsurface layers. FIG. 5 Resistivity Sounding Curve (from Benson et al, (8)) 5.7.2 Successive electrode spacings should be (approximately) equally spaced on a logarithmic scale. Normally, 3 to 6 data points per decade should be measured. A resistivity sounding curve obtained from measurements of a uniform layered medium should follow a smooth curve, (Fig. 5). By using six points per decade, noise is generally less significant and a smooth sounding curve may be obtained. Data should be plotted in the field to ensure that an adequate number of noise-free measurements are made. 5.7.3 The depth of penetration for an inhomogeneous stratified earth depends upon the electrode separation and the resistivities of the earth's layers. In general, the overall array length could be many times the exploration depth. 5.8 Profiling Measurements—A series of profile measurements along a line is used to assess lateral changes in subsurface conditions at a given depth (Fig. 6). Electrical resistivity profiling is accomplished by making measurements with fixed electrode spacing and array geometry at several stations along a profile line (Fig. 7). A single profile measurement results in an apparent electrical resistivity value at a station. Several profiles over an area can be used to produce a contour map of changes in subsurface conditions (Fig. 8). These apparent resistivity profiles or maps cannot be interpreted in terms of layer resistivity values without sounding data or other additional information. FIG. 6 Profiling to Assess Lateral Changes (from Zohdy et al, (12)) FIG. 7 Stations Along a Profile (from Benson et al, (8)) FIG. 8 Apparent Resistivity Contour Map (from Zohdy et al, (12)) 5.8.1 Vertical soundings are used to determine the appropriate electrode spacing for profiling. Small electrode spacings can be used to emphasize shallow variations in resistivity that may affect the interpretation of deeper data. Spacing between measurements controls the lateral resolution that can be obtained from a series of profile measurements. 1.1 Purpose and Application:  1.1.1 This guide summarizes the equipment, field procedures, and interpretation methods for the assessment of the electrical properties of subsurface materials and their pore fluids, using the direct current (DC) resistivity method. Measurements of the electrical properties of subsurface materials are made from the land surface and yield an apparent resistivity. These data can then be interpreted to yield an estimate of the depth, thickness, voids, and resistivity of subsurface layer(s). 1.1.2 Resistivity measurements as described in this guide are applied in geological, geotechnical, environmental, and hydrologic investigations. The resistivity method is used to map geologic features such as lithology, structure, fractures, and stratigraphy; hydrologic features such as depth to water table, depth to aquitard, and groundwater salinity; and to delineate groundwater contaminants. General references are, Keller and Frischknecht (1),2 Zohdy et al (2), Koefoed (3), EPA(4), Ward (5), Griffiths and King (6), and Telford et al (7). 1.1.3 This guide does not address the use tomographic interpretation methods, commonly referred to as electrical resistivity tomography (ERT) or electrical resistivity imaging (ERI). While many of the principles apply the data acquisition and interpretation differ from those set forth in this guide. 1.2 Limitations:  1.2.1 This guide provides an overview of the Direct Current Resistivity Method. It does not address in detail the theory, field procedures, or interpretation of the data. Numerous references are included for that purpose and are considered an essential part of this guide. It is recommended that the user of the resistivity method be familiar with the references cited in the text and with the Guide D420, Practice D5088, Practice D5608, Guide D5730, Test Method G57, D6429, and D6235. 1.2.2 This guide is limited to the commonly used approach for resistivity measurements using sounding and profiling techniques with the Schlumberger, Wenner, or dipole-dipole arrays and modifications to those arrays. It does not cover the use of a wide range of specialized arrays. It also does not include the use of spontaneous potential (SP) measurements, induced polarization (IP) measurements, or complex resistivity methods. 1.2.3 The resistivity method has been adapted for a number of special uses, on land, within a borehole, or on water. Discussions of these adaptations of resistivity measurements are not included in this guide. 1.2.4 The approaches suggested in this guide for the resistivity method are the most commonly used, widely accepted and proven; however, other approaches or modifications to the resistivity method that are technically sound may be substituted if technically justified and documented. 1.2.5 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgements. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process. 1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method. 1.4 Precautions:  1.4.1 It is the responsibility of the user of this guide to follow any precautions in the equipment manufacturer's recommendations and to consider the safety implications when high voltages and currents are used. 1.4.2 If this guide is used at sites with hazardous materials, operations, or equipment, it is the responsibility of the user of this guide to establish appropriate safety and health practices and to determine the applicability of regulations prior to use. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 646元 / 折扣价： 550 元 加购物车

This test method covers the determination of the electrical resistivity of metallic electrical conductor material. Weight resistivity accuracy may be adversely affected by possible inaccuracies in the assumed density of the conductor. The definition of resistivity and the equations for calculating volume resistivity and weight resistivity are given. Resistance shall be measured using an apparatus with a circuit configuration and instrumentation that has a resistance measurement capability of the prescribed accuracy. The test specimen requirements and the test procedure including: (1) determination of dimensions (such as length and cross-section), weight, and density, and (2) resistance measurement are detailed. The formula for calculating the corrected resistance, when the measurement is made at any temperature other than a reference temperature, is given. No statement of precision has been made and no work has been planned to develop such a statement. This test method has no bias because the value for resistivity is determined solely in terms of this test method.1.1 This test method covers the determination of the electrical resistivity of metallic electrical conductor material. It provides for an accuracy of ±0.30 % on test specimens having a resistance of 0.00001 Ω (10 μΩ) or more. Weight resistivity accuracy may be adversely affected by possible inaccuracies in the assumed density of the conductor.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Conductivity measurements are typically made on samples of moderate to high ionic strength where contamination of open samples in routine laboratory handling is negligible. Under those conditions, standard temperature compensation using coefficients of 1 to 3 % of reading per degree Celsius over wide concentration ranges is appropriate. In contrast, this test method requires special considerations to reduce trace contamination and accommodates the high and variable temperature coefficients of pure water samples that can range as high as 7 % of reading per degree Celsius. In addition, measuring instrument design performance must be proven under high purity conditions.5.2 This test method is applicable for detecting trace amounts of ionic contaminants in water. It is the primary means of monitoring the performance of demineralization and other high purity water treatment operations. It is also used to detect ionic contamination in boiler waters, microelectronics rinse waters, pharmaceutical process waters, etc., as well as to monitor and control the level of boiler and power plant cycle chemistry treatment chemicals. This test method supplements the basic measurement requirements for Test Methods D1125, D2186, and D4519.5.3 At very low levels of alkaline contamination, for example, 0–1 μg/L NaOH, conductivity is suppressed, and can actually be slightly below the theoretical value for pure water. (1 and 2)4 Alkaline materials suppress the highly conductive hydrogen ion concentration while replacing it with less conductive sodium and hydroxide ions. This phenomenon is not an interference with conductivity or resistivity measurement itself but could give misleading indications of inferred water purity in this range if it is not recognized.1.1 This test method covers the determination of electrical conductivity and resistivity of high purity water samples below 10 μS/cm (above 0.1 Mohm-cm). It is applicable to both continuous and periodic measurements but in all cases, the water must be flowing in order to provide representative sampling. Static grab sampling cannot be used for such high purity water. Continuous measurements are made directly in pure water process lines, or in side stream sample lines to enable measurements on high temperature or high pressure samples, or both.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 The electrical resistivity of a concrete is the opposition to the movement of ions under an applied electric field. The electrical conductivity of a concrete is a measure of how readily the ions in the pore solution can be transported through the concrete under an applied electric field (the higher the conductivity, the greater the rate of transport). The electrical resistivity or conductivity is a material property that depends upon the pore volume, the pore structure (size and connectivity), the pore solution composition, the degree of saturation of the concrete specimen, and the specimen’s temperature. Concrete mixture characteristics that are known to affect concrete electrical resistivity, as well as resistance to chloride ion penetration, include water-cementitious materials ratio, pozzolans, slag cement, the presence of polymeric admixtures, air-entrainment, aggregate type, aggregate volume fraction, degree of consolidation, curing method, and age.5.2 The bulk electrical resistivity of concrete is the inverse of its bulk electrical conductivity. Bulk electrical conductivity can also be measured by Test Method C1760, which uses the apparatus described in Test Method C1202. This test method, however, uses apparatus specifically designed to measure bulk conductivity or bulk resistivity.5.3 The purpose of conditioning in a simulated pore solution is to bring the specimen to a level of near complete saturation of the capillary and gel pores. When comparing two different concrete specimens, it is important to condition both specimens as close as possible to a comparable saturation state, using the same solution for conditioning, so that values can be compared in a meaningful way. This is particularly true for using the measured resistivity or conductivity, along with other information, to estimate the diffusivity.5.4 The bulk electrical resistivity or conductivity of concrete can provide a rapid indication of its resistance to chloride ion penetration and resistance to penetration of other fluids. Resistivity or conductivity measurements have shown good correlations with other electrical indication tests including Test Method C1202 (1, 2, 3).6 Bulk electrical resistivity results have shown good correlation with bulk diffusion determined using Test Method C1556 on companion molded cylinders from the same concrete mixtures (4).1.1 This test method covers the determination of the bulk electrical resistivity or conductivity of molded specimens or cored sections of hardened concrete after immersion in water saturated with a simulated pore solution in order to provide a rapid indication of its resistance to the penetration of fluids and dissolved aggressive ions.1.2 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. If required results obtained from another standard are not reported in the same system of units as used by this standard, it is permitted to convert those results using the conversion factors found in the SI Quick Reference Guide.21.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.)3 For specific warning statement see 8.1.2.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车