scholarly journals Comparison of the Capacitance Method and the Microwave Impulse Method for Determination of Moisture Profiles in Building Materials

10.14311/670 ◽  
2005 ◽  
Vol 45 (1) ◽  
Author(s):  
P. Tesárek ◽  
J. Pavlík ◽  
R. Černý
Keyword(s):  
Moisture Content ◽  
Building Materials ◽  
Basic Principles ◽  
Porous Building Materials ◽  
Calibration Process ◽  
Impulse Method ◽  
Measuring Methods ◽  
Capacitance Method ◽  
Moisture Profiles

A comparison of the capacitance method and the microwave impulse method for the determination of moisture profiles in three typical porous building materials is presented in this paper. The basic principles of the measuring methods are given. The calibration process is described in detail. On the basis of the measured results, it can be concluded that the capacitance method provides better accuracy in the range of lower moisture content than to the microwave impulse method, which is more accurate for the highest values of moisture content. 

scholarly journals Time Domain Reflectometry (TDR) technique – A solution to monitor moisture content in construction materials

2020 ◽  
Vol 172 ◽  
pp. 17001
Author(s):  
Teresa Stingl Freitas ◽  
Ana Sofia Guimarães ◽  
Staf Roels ◽  
Vasco Peixoto de Freitas ◽  
Andrea Cataldo
Keyword(s):  
Moisture Content ◽  
Time Domain ◽  
Building Materials ◽  
Correct Diagnosis ◽  
Construction Materials ◽  
Gravimetric Method ◽  
Reference Method ◽  
Time Domain Reflectometry ◽  
Relative Dielectric Permittivity ◽  
Porous Building Materials

Measuring moisture content in building materials is crucial for the correct diagnosis of buildings’ pathologies and for the efficiency evaluation of the treatment solution applied. There are several different techniques available to measure the moisture content in construction materials. However, perform long-term minor-destructive measurements is still a great challenge. The TDR – Time Domain Reflectometry – technique is commonly used for moisture content measurements in soils, but is considered a relatively new method with regard to its application in construction materials. In the present state of research, the current use of the TDR technique for monitoring moisture content in all types of consolidated porous building materials is not possible yet. Indeed, the empirical conversion functions proposed for soils are mostly not suitable for building materials. Furthermore, to successfully use the TDR technique, a good contact between the TDR probe and the material under study is required, which may be difficult to achieve in hard materials. In this paper, the TDR technique was implemented in two limestone walls constructed in the lab to test experimentally the efficiency of a wall-base ventilation channel to speed up drying after a flood. Each wall was equipped with four two-rod TDR probes for continuous monitoring the moisture content in both situations: with and without the ventilation channel. All the equipment used, procedures followed during the drilling until the probes’ final installation, as well as the individual calibration required for each probe are explained in detail. Instead of using unsuitable functions proposed for soils, the evaluation of the moisture content from the apparent relative dielectric permittivity measured was established using as reference method the gravimetric method. The results obtained suggest that the TDR technique is suitable for moisture content monitoring in consolidated porous building materials.

Quantitative, zerstörungsfreie Feuchtemessung in Baustoffen vor Ort mit der Time Domain Reflectometry / Quantitative, non-destructive moisture measurement in building materials on site by time-domain re ectometry

1999 ◽  
Vol 5 (6) ◽  
pp. 609-618
Author(s):  
M. Stacheder ◽  
G. Grassegger ◽  
F. Grüner
Keyword(s):  
Time Domain ◽  
Building Materials ◽  
Salt Content ◽  
Time Domain Reflectometry ◽  
New Method ◽  
Measuring Methods ◽  
Surface Moisture ◽  
Non Destructive ◽  
Floor Cover

Abstract A new commercially available dielectric technique for the non-destructive determination of moisture in building materials based on the principle of 'time-domain reflectometry' (TDR) is presented. TDR measurements on samples of sandstone, brick, concrete and floor cover matched very well with results of conventional moisture measuring methods such as oven-drying or calciumcarbide-technique. The new method showed only a low influence of salt content or surface moisture of the material on the results.

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