Validation of Selected Non-Destructive Methods for Determining the Compressive Strength of Masonry Units Made of Autoclaved Aerated Concrete

Abstract

Minor-destructive (MDT) and non-destructive (NDT) techniques are not commonly used for masonry as they are complex and difficult to perform. This paper describes validation of the following methods: semi-non-destructive, non-destructive, and ultrasonic technique for autoclaved aerated concrete (AAC). The subject of this study covers the compressive strength of AAC test elements with declared various density classes of: 400, 500, 600, and 700 (kg/m3), at various moisture levels. Empirical data including the shape and size of specimens, were established from tests on 494 cylindrical and cuboid specimens, and standard cube specimens 100 mm × 100 mm × 100 mm using the general relationship for ordinary concrete (Neville’s curve). The effect of moisture on AAC was taken into account while determining the strength fBw for 127 standard specimens tested at different levels of water content (w = 100%, 67%, 33%, 23%, and 10%). Defined empirical relations were suitable to correct the compressive strength of dry specimens. For 91 specimens 100 mm × 100 mm × 100 mm, the P-wave velocity cp was tested with the transmission method using the ultrasonic pulse velocity method with exponential transducers. The curve (fBw–cp) for determining the compressive strength of AAC elements with any moisture level (fBw) was established. The developed methods turned out to be statistically significant and can be successfully applied during in-situ tests. Semi-non-destructive testing can be used independently, whereas the non-destructive technique can be only applied when the developed curve fbw–cp is scaled.

Tests of Concrete Strength across the Thickness of Industrial Floor Using the Ultrasonic Method with Exponential Spot Heads

“…The compressive strength of concrete samples in their various cross-sections was determined with the use of the non-destructive method calibrated with the destructive tests of the samples. This type of examination is being widely used for the range of building materials, such as concrete, wood, steel, ceramics, and for the diagnostics of building structures [20][21][22][23][24][25]. Tests were carried out with the use of the ultrasound method based on longitudinal wave velocities [26].…”

Use of TLS (LiDAR) for Building Diagnostics with the Example of a Historic Building in Karlino

“…The majority of analyses of existing structures are based on visual inspection, searching for visible cracks on the walls or slabs and others [1][2][3][4]. In some cases, special equipment is used, including sclerometers, ultrasonic emitter, radar or other non-destructing material testing methods [5][6][7][8]. Less popular are high-precision measuring techniques used only in case of uneven settling or extreme cases (excessive deflections of slabs).…”

Ultrasonic Pulse Velocity—Compressive Strength Relationship for Portland Cement Mortars Cured at Different Conditions

“…Ultrasonic pulse velocity (UPV) is a non-destructive test method (NDT) that may be easily applied in both laboratory and field conditions. It is increasingly being used to estimate some microstructural [4][5][6][7][8] and mechanical [9,10] properties of cement-based materials. Non-destructive testing using ultrasound (NDT-UPV) has been also used in monitoring of setting and strength development of ultra-high-performance concrete [11], monitoring of mortar and concrete hardening [12,13], and detection of rebars in concrete [14,15].…”