Acoustic non-destructive testing of high temperature degraded concrete with comparison of acoustic impedance

The paper is focused on non-destructive measurement of high temperature degraded concrete test specimens of three mixtures different by the use of coarse aggregate. Testing is done by ultrasonicpulse velocitymethod and Impact-Echo method. Non-destructive results are compared with destructive tests. Ultrasonic pulse velocity, dominant resonance frequency and acoustic impedance are discussed and compared with changes in density, cubic compressive strength, and tensile strength of concrete. The paper suggests possible assessment of degraded concrete by the change in acoustic impedance dependent on residual tensile strength

NON-DESTRUCTIVE TESTING AND X-RAY DIFFRACTION ANALYSIS OF HIGH-TEMPERATURE DEGRADED CONCRETE

In the field of civil engineering a diagnostics acoustic non-destructive testing is widely used and in the past years it was used even in testing of high-temperature degraded concrete structures. These methods can provide specific information about the physical-mechanical state of material; however physical-chemical changes in microstructure are measurable to a limited extent. This article is focused on non-destructive and destructive testing of high-temperature degraded concrete test beams of dimensions 0.1 × 0.1 × 0.4 m fired at 200 − 1200 °C. The Impact-Echo method and ultrasonic velocity pulse method measurements are compared with destructive test results. Testing of measured changes in the p-m properties of reference and fired samples is then supplemented by X-ray diffraction analysis, in order to document mineralogical physical-chemical changes of tested material

Acoustic non-destructive testing of high temperature degraded concrete with comparison of acoustic impedance

The paper is focused on non-destructive measurement of high temperature degraded concrete test specimens of three mixtures different by the use of coarse aggregate. Testing is done by ultrasonicpulse velocitymethod and Impact-Echo method. Non-destructive results are compared with destructive tests. Ultrasonic pulse velocity, dominant resonance frequency and acoustic impedance are discussed and compared with changes in density, cubic compressive strength, and tensile strength of concrete. The paper suggests possible assessment of degraded concrete by the change in acoustic impedance dependent on residual tensile strength

Monitorování betonu při hydrataci elektrický zaměřenou metodou

Analysis of impedance spectra of inhomogeneous materials is a part of the impedance spectroscopy which is still waiting for its development. Materials having higher electric resistance values (over 500 kohm) can be considered – under certain simplifying assumptions – as dielectrics. A theory of dielectric polarization was formulated by Debye for homogeneous materials.Analýza spekter impedance nehomogenních materiálů je součástí impedanční spektroskopie, která čeká na svůj rozvoj. Materiály, které mají vyšší hodnoty elektrického odporu (přes 500 kohm) lze považovat – za určitých předpokladů – dielektrika. Teorie dielectric polarizací formuloval Debye u homogenních materiálů

Vlivu příměsi uhlíku na elektrické vlastnosti struskových malt

New materials based on alkali-activated slag mortars may be an important contribution of applied research, which strives to offer the use of waste materials as a full replacement for the currently used binders and explores the impact of forms of carbon incorporation on the physical and mechanical properties. The unique Vector analyzer RaS ZNC with a coaxial probe DAK-12 from Speag was used to determine permittivity and loss factor, electrical resistance was measured using two channel oscilloscope.Aplikovaný výzkum, se snaží nabídnout využití odpadních materiálů jako plnou náhradu za aktuálně používaná pojiva K testování byl využit moderní vektorový analyzátor, ZNC RaS s koaxiální sonda DAK-12 od firmy Speag, který byl použit k určení permitivity, ztrátového činitele a elektrického odporu