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

Abstract

Semi-destructive and non-destructive techniques are not commonly used for masonry as they are complex and difficult to perform. This paper describes validation of the following methods: semi-destructive and non-destructive, ultrasonic technique for autoclaved aerated concrete (AAC). The research subject was the compressive strength of AAC test elements with declared various density classes of: 400, 500, 600 and 700 (kg/m3) and 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 100×100×100 mm using the general relationship for standard 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 can be used to correct the compressive strength of dry specimens. For 91 specimens 100×100×100 mm, the P-wave velocity cp was tested with the transmission method using 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.

Finite Element Study on the Shear Capacity of Traditional Joints between Walls Made of AAC Masonry Units

“…Accurate numerical analysis of multi-material constructions is complex because it requires determination of many material parameters. Assumption of the yield surface requires results of material tests in uniaxial and complex load conditions [ 27 , 28 , 29 , 30 ] or samples of unusual shapes [ 31 ]. In addition to the criteria of material failure, it is also necessary to specify various parameters describing the phenomena occurring at the interface of the combined materials, e.g., reinforcement and concrete or masonry and mortar.…”

Moisture Influence on Compressive Strength of Calcium Silicate Masonry Units–Experimental Assessment and Normative Calculations

“…The effect of sorption capacity on the mechanical properties of unfired clay bricks was investigated in [ 31 ]. The validation of selected non-destructive techniques of determining the compressive strength of masonry units was described in [ 32 ]. The researchers dealt with semi-non-destructive, non-destructive and ultrasonic methods used for autoclaved aerated concrete, in the four density classes of 400, 500, 600 and 700 kg/m 3 , tested at various moisture contents.…”

Feasibility of a Thermography Nondestructive Technique for Determining the Quality of Historical Frescoed Masonries: Applications on the Templar Church of San Bevignate

“…Regarding the innovative techniques, these include the use of tools such as laser scanners, digital photogrammetry and thermal cameras which, if applied correctly and adequately integrated with other methods, allow different levels of definition of the state of conservation and of the structural peculiarities keeping the artefacts from damaging during the survey [5][6][7][8]. In particular, frescoed walls and decorated vaults, due to the executive techniques and the materials used, cannot be restored if damaged during the investigation phases and moreover suffer from the effects of the deterioration of time (thermal effects, humidity, solar radiation).…”