Methodology of Moisture Measurement in Porous Materials Using Time Domain Reflectometry / Metodyka Prowadzenia Badań Wilgotności W Ośrodkach Porowatych Za Pomocą Reflektometrii W Domenie Czasu

Abstract The article presents the description of measurement methodology of moisture transport in unsaturated porous materials using Time Domain Reflectometry (TDR) technique on the example of measurement of capillary uptake phenomenon in the sample of autoclaved aerated concrete (AAC). In the paper there are presented basic principles of the TDR method as a technique applied in metrology, its potential for measurement of moisture in porous materials like soils and porous building materials. Second part of the article presents the experiment of capillary rise process in the sample of AAC. Within the experiment moisture content was monitored in the sample exposed on water influence. Monitoring was conducted using TDR FP/mts probes. Preparation of the measuring setup was presented in detail. The TDR readouts post-processing, graphical presentations of the obtained results, short discussion and comparison of TDR readouts to gravimetric measurement were also presented.

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A Noninvasive TDR Sensor to Measure the Moisture Content of Rigid Porous Materials

Sensors ◽

10.3390/s18113935 ◽

2018 ◽

Vol 18 (11) ◽

pp. 3935 ◽

Cited By ~ 12

Author(s):

Zbigniew Suchorab ◽

Marcin Widomski ◽

Grzegorz Łagód ◽

Danuta Barnat-Hunek ◽

Dariusz Majerek

Keyword(s):

Moisture Content ◽

Porous Materials ◽

Building Materials ◽

Capillary Rise ◽

Capacitive Sensor ◽

Time Domain Reflectometry ◽

Capillary Uptake ◽

Individual Calibration ◽

Sample Application ◽

The Time Domain

The article presents the potential application of the time domain reflectometry (TDR) technique to measure moisture transport in unsaturated porous materials. The research of the capillary uptake phenomenon in a sample of autoclaved aerated concrete (AAC) was conducted using a TDR sensor with the modified construction for non-invasive testing. In the paper the basic principles of the TDR method as a technique applied in metrology, and its potential for measurement of moisture in porous materials, including soils and porous building materials are presented. The second part of the article presents the experiment of capillary rise process in the AAC sample. Application of the custom sensor required its individual calibration, thus a unique model of regression between the readouts of apparent permittivity of the tested material and its moisture was developed. During the experiment moisture content was monitored in the sample exposed to water influence. Monitoring was conducted using the modified TDR sensor. The process was additionally measured using the standard frequency domain (FD) capacitive sensor in order to compare the readouts with traditional techniques of moisture detection. The uncertainty for testing AAC moisture, was expressed as RMSE (0.013 cm3/cm3) and expanded uncertainty (0.01–0.02 cm3/cm3 depending on moisture) was established along with calibration of the applied sensor. The obtained values are comparable to, or even better than, the features of the traditional invasive sensors utilizing universal calibration models. Both, the TDR and capacitive (FD) sensor enabled monitoring of capillary uptake phenomenon progress. It was noticed that at the end of the experiment the TDR readouts were 4.4% underestimated and the FD readouts were overestimated for 12.6% comparing to the reference gravimetric evaluation.

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Moisture measurements of the chalk rock walls from Kazimierz Dolny with the application of TDR method

Budownictwo i Architektura ◽

10.35784/bud-arch.2317 ◽

2008 ◽

Vol 2 (1) ◽

pp. 125-140

Author(s):

Zbigniew Suchorab ◽

Danuta Barnat-Hunek ◽

Henryk Sobczuk

Keyword(s):

Time Domain ◽

Building Materials ◽

Capillary Rise ◽

Good Alternative ◽

Time Domain Reflectometry ◽

Composition Analysis ◽

Physical Parameters ◽

Water Parameters ◽

Vistula River ◽

Structure Changes

The article presents monitoring measurements of the physical parameters and mineralogical-petrographical composition analysis of the chalk rock from the Kazimierz Dolny region. The experiments involve the reflectometric techniques TDR (Time Domain Reflectometry) as a perspective alternative in moisture determinations. The investigation domain was the stone from the Castle of Janowiec by the Vistula river, which walls indicate the progressive corrosion depending on external exposition and age. Other object of investigations was the stone from quarry in Kazimierz Dolny. Porosimetric examinations of the chalk rock from the southern and northern elevation of the castle indicate differences in structure changes of the stones. These differences influence different behaviour of the chalk rock during capillary rise of water and salt solutions. It is connected with the suitable matching of the conservation protection, wall protecting preparations which kind and application depend on porosimetric parameters of the material. The TDR method is applied as a good alternative of water transport measurement in porous building materials and other water parameters characterisig described material.

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Capillary Uptake Monitoring in Lime-Hemp-Perlite Composite Using the Time Domain Reflectometry Sensing Technique for Moisture Detection in Building Composites

Materials ◽

10.3390/ma13071677 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1677 ◽

Cited By ~ 3

Author(s):

Przemysław Brzyski ◽

Zbigniew Suchorab

Keyword(s):

Thermal Conductivity ◽

Apparent Density ◽

Time Domain ◽

Building Materials ◽

Gravimetric Method ◽

Total Porosity ◽

Time Domain Reflectometry ◽

Partial Replacement ◽

Wall Material ◽

Capillary Uptake

The use of waste plants in the production of building materials is consistent with the principles of sustainable development. One of the ideas involves using hemp shives as an aggregate for the production of a composite used as a filling of the timber frame construction of the walls. The most important disadvantage of using the building materials based on organic components is their susceptibility to the water influence. The wall material is exposed to rising groundwater. The research part of the paper presented the preparation method and the investigation of the hemp-perlite-lime composites. Flexural and compressive strength, apparent density, total porosity, thermal conductivity, and mass absorptivity were examined. The main research part pertained to the analysis of capillary uptake occurrence in the composites, being the important phenomenon present in the external walls. The study on this phenomenon was carried out using the technique of indirect moisture evaluation—Time Domain Reflectometry (TDR). The indirect readouts were additionally verified with the traditional evaluation using the gravimetric method based on the PN-EN 1925 standard. The study proved that the tested composites were characterized by low apparent density, thermal conductivity, strength parameters, high total porosity, and mass absorptivity. The partial replacement of hemp shives by expanded perlite had a beneficial effect on the tested properties of composites.

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A Review of Modern CMOS Transimpedance Amplifiers for OTDR Applications

Electronics ◽

10.3390/electronics8101073 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1073 ◽

Cited By ~ 1

Author(s):

Agata Romanova ◽

Vaidotas Barzdenas

Keyword(s):

Time Domain ◽

Figure Of Merit ◽

Low Cost ◽

Performance Comparison ◽

Time Domain Reflectometry ◽

Basic Principles ◽

Transimpedance Amplifiers ◽

Concise Review ◽

Optical Time Domain Reflectometry ◽

Optical Time

The work presents a review of modern CMOS transimpedance amplifiers (TIAs) in the context of their application for low-cost optical time-domain reflectometry (OTDR). After introducing the basic principles behind the OTDR, the requirements for a suitable CMOS TIA are presented and discussed. A concise review of several basic TIA topologies is provided with a brief overview of their main properties. A detailed discussion is given on a representative set of approaches reported in the literature and the figure of merit (FOM) is introduced as a unified basis for performance comparison. Limitations of a single FOM as a basis for comparison are pointed out. Based on the provided discussion, some suggestions are made on the suitability of the TIA topologies for OTDR applications.

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

E3S Web of Conferences ◽

10.1051/e3sconf/202017217001 ◽

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.

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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

Restoration of Buildings and Monuments ◽

10.1515/rbm-1999-5423 ◽

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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The analysis of heat conductivity coefficient of the aerated concrete building barriers depending on moisture changes

Budownictwo i Architektura ◽

10.35784/bud-arch.2262 ◽

2011 ◽

Vol 8 (1) ◽

pp. 107-116

Author(s):

Zbigniew Suchorab ◽

Danuta Barnat-Hunek

Keyword(s):

Heat Conductivity ◽

Building Materials ◽

Winter Season ◽

Time Domain Reflectometry ◽

Heat Conductivity Coefficient ◽

Water Desorption ◽

Concrete Building ◽

Absorbing Material ◽

Aerated Concrete ◽

Comfort Parameters

The article is sacrificed to the aerated concrete building barriers moisture phenomenon. Water, which increases heat conductivity of building materials is the reason of the increased heat loses during the winter season. The result of this phenomenon is the decrease of indoor heat comfort parameters. Aerated concrete is a strongly water absorbing material with elongated time of water desorption. Capillary-porous structure of the described medium makes is highly prone to water influence what is the reason of the detailed analysis of heat conductivity coefficient in relation to moisture. In this article it is analyzed and compared the influence of moisture changes on heat parameters of the aerated concrete with the bulk densities of 400 and 600 kg/m3 using the reflectometric techniques TDR (Time Domain Reflectometry).

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Is the Time-Domain Reflectometry (TDR) Technique Suitable for Moisture Content Measurement in Low-Porosity Building Materials?

Sustainability ◽

10.3390/su12197855 ◽

2020 ◽

Vol 12 (19) ◽

pp. 7855 ◽

Cited By ~ 1

Author(s):

Teresa Stingl Freitas ◽

Ana Sofia Guimarães ◽

Staf Roels ◽

Vasco Peixoto de Freitas ◽

Andrea Cataldo

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Time Domain ◽

Building Materials ◽

Construction Materials ◽

Gravimetric Method ◽

Time Domain Reflectometry ◽

Advantages And Disadvantages ◽

The Time Domain ◽

Low Porosity

Measuring moisture content in building materials is essential both for professional practice and for research. However, this is a very complex task, especially when long-term minor destructive measurements are desired. The time-domain reflectometry (TDR) technique is commonly used for soil moisture measurements, but its application in construction materials is considered a relatively new method, particularly for low-porosity building materials. The major obstacles to its current use in construction materials are (1) the difficulty of ensuring good contact between the TDR probe and the material, and (2) the lack of appropriate conversion functions between the measured relative permittivity and the moisture content of building materials. This paper intends to contribute to overcoming these difficulties by explaining in detail all the required steps to monitor moisture content in real-scale limestone walls. For that, a device is presented to guarantee the correct installation of the TDR probes on the walls, and a calibration procedure through the gravimetric method is proposed to avoid the use of an unsuitable calibration function developed for soil moisture measurements. In addition, the importance of the individual probe calibration is discussed, as well as TDR advantages and disadvantages for construction materials. The results obtained so far reveal that the TDR technique is suitable to detect moisture content variations in limestone, which is a low-porosity building material.

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