Method of measuring effect of alkali-silicate reaction (ASR) in experimental mortar bodies (EMB) by ultrasonic irradiation

摘要

So far used method of determining effect of an alkali-silicate reaction (ASR) in experimental mortar bodies – EMB (6) by expansion measurement is replaced by ultrasonic irradiation in the longitudinal direction of the samples. The ultrasonic irradiation can be carried out manually or automatically with a selected time interval from units of minutes up to several days. There are used ultrasonic sensors of both longitudinal P and transverse S (2, 3). Detected signals are processed in both frequency and time regions. The expansion measurement exhibits measuring sensitivity at the most up to 1 percent of total change, while the ultrasonic measuring methods, especially velocity of propagation and change in amplitude of the first application and maximum amplitude, exhibit changes in extent of more than 50 percent. Semiautomatic, optionally manual measurements make it possible to determine these parameters in the course of fortnight test. The propagation velocity of P and S wave motions make it possible to determine elastic dynamic modules and their changes of EMB (6), which exhibit more than 0.1 percent of the change in length can be considered as reactive. The greater is the decrease of the ultrasound-determined parameters, the greater is the aggregate reactivity in the samples being tested.