Investigation of dielectric properties of brick materials as a function of moisture and salt content using a microwave impulse technique at very high frequencies

Maierhofer, Ch.; Wöstmann, Jens

doi:10.1016/s0963-8695(98)00011-5

Cited by 35 publications

(9 citation statements)

References 2 publications

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“…The problem of strength deterioration as a result of moistness has been analyzed in many articles. The researchers dealt with techniques of moisture content measurement (e.g., [ 26 ]) and assessed its impact on masonry units, mortar and wall strengths (e.g., [ 27 ]). In [ 28 ], the compressive strength of fired-clay bricks, cement mortar and hydraulic lime mortar are investigated in dry and saturated conditions.…”

Section: Introductionmentioning

confidence: 99%

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

2020

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This paper primarily assesses the scale of adverse changes to the compressive strength of different types of silicates due to the influence of moisture. The study covers three groups of silicate units of different strength classes—15, 20 and 25—obtained from three different manufacturers. It was demonstrated that in all studied groups, moisture significantly decreased the compressive strength by about 30–40%. In addition, microstructural studies were conducted to analyze the relationship between the specific porosity structure of each group of silicate bricks and their compressive strength. On the basis of SEM (Scanning Electron Microscopy) and EDS (Electron Dispersive Spectroscopy) analysis, the elemental composition of individual silicates was determined and the contact zone between the aggregate and the binder was determined, which largely influenced the obtained compressive strength of each silicates. Next, the study referred to the utility of the normative procedure used to determine the strength class of samples with different geometries and at different moisture concentrations. The results of the calculations showed the high accuracy of the normative-based assessment of strength class, regardless of the manufacturer and the moisture values during examination.

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Section: Introductionmentioning

confidence: 99%

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

2020

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“…Used as early as 1975 in archaeological surveys13, the method is currently being used for investigating a number of masonry conditions: detecting inclusions, voids, and other defects14; characterizing multi‐wythe walls15; locating bond stones and header courses; determining thickness of retaining walls; locating grout in reinforced masonry construction16,17; identifying horizontal and vertical reinforcing bars or embedded structural steel members17; determining effectiveness of repair techniques18; qualifying the state of internal damage or deterioration in walls; measuring moisture content19, 20; locating regions with high salt content20,21. …”

Section: Nondestructive Test Methodsmentioning

confidence: 99%

Nondestructive testing and damage assessment of masonry structures

Schüller

2003

Progress Structural Eng Maths

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Recent advances in nondestructive testing technology have led to mainstream use of several methods for evaluating masonry construction. Nondestructive approaches such as rebound hardness, stress wave transmission, impact-echo, surface penetrating radar, tomographic imaging, and infrared thermography are useful for qualitative condition surveys as well as identification of internal features such as voids or areas of distress. In situ test methods are also available for determination of engineering properties. Flatjack methods are used to measure the state of compressive stress and compression response, masonry bed joint shear stress may be evaluated by an in situ shear test, and mortar unit bond strength is tested by an adaptation of the bond wrench approach. Standardized methods exist for many of the evaluation approaches and related efforts are ongoing within ASTM and RILEM.

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“…Following on from the work of Maierhofer and Wӧstmann, [60], Pavlĺk et al [62] designed a pulsed radar microwave system for monitoring the moisture content (free water) of early age cements that they envisioned could be used in both the laboratory and on site. Changes in free water were then correlated to results of mechanical tests.…”

Section: Non-destructive Testing and Evaluation Cure-state Monitorinmentioning

confidence: 99%

Microwave processing of cement and concrete materials – towards an industrial reality?

Buttress

Jones

Kingman

2015

Cement and Concrete Research

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Each year a substantial body of literature is published on the use of microwaves to process cement and concrete materials. Yet to date, very few if any have lead the realisation of a commercial scale industrial system and is the context under which this review has been undertaken.The state-of the-art is evaluated for opportunities, and the key barriers to the development of new microwave-based processing techniques to enhance production, processing and recycling of cement and concrete materials. Applications reviewed include pyro-processing of cement clinker; accelerated curing, non-destructive testing and evaluation (NDT&E), and end-of-life processing including radionuclide decontamination.

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Investigation of dielectric properties of brick materials as a function of moisture and salt content using a microwave impulse technique at very high frequencies

Cited by 35 publications

References 2 publications

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

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

Nondestructive testing and damage assessment of masonry structures

Microwave processing of cement and concrete materials – towards an industrial reality?

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