COMPRESSION STRENGTH MEASURING METHOD AND INSTRUMENT OF CONCRETE STRUCTURE

摘要

A method for non-destructively measuring concrete strength easily and quickly on a measuring site with high precision. A wideband ultrasonic wave is originated from an origination probe provided in a concrete model, waves received by a receiving probe are averaged arithmetically, a receiving wave thus acquired is multiplied by a predetermined time function and a specific part is clipped, the clipped wave is subjected to Fourier transform analysis or maximum entropy analysis to determine a spectrum, the frequency indicative of the position of maximum value of that spectrum is determined, a linear regression equation of the frequency and compression strength at a position showing the maximum value of spectrum is determined, a frequency indicative of the position of the maximum value of spectrum is determined for the concrete to be measured, and the compression strength is determined from the linear regression equation.