SI base unit referenced to the values of the fundamental constants, namely the Planck constant ("h"), the electron charge ("e"), the Boltzmann constant ("k"), and the Avogadro constant ("N"). This approach was approved in 2018, only after measurements of these constants were achieved with sufficient accuracy. SI base unit The International System of Units (SI) defines seven units of measure as a basic set from which all other SI units can be derived. The SI base units and their physical quantities are the meter for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin
Electrical resistivity measurement of concrete to: When the electrical resistivity of the concrete is low, the rate of corrosion increases. When the electrical resistivity is high, e.g. in case of dry and carbonatated concrete, the rate of corrosion decreases. Nondestructive testing Electrical resistivity measurement of concrete Concrete electrical resistivity can be obtained by applying a current into the concrete and measuring the response voltage. There are different methods for measuring concrete resistivity. Concrete electrical resistance can be measured by applying a current using two electrodes attached to the ends of a uniform cross-section specimen. Electrical resistivity is obtained from the equation: This method suffers from