Test Method for Determination of Water (Moisture) Content of Soil by the Time-Domain Reflectometry (TDR) Method

10.1520/d6565 ◽  
2014 ◽  
Author(s):  
Keyword(s):  
Moisture Content ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Test Method ◽  
The Time Domain

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

2020 ◽  
Vol 12 (19) ◽  
pp. 7855 ◽  
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.

Determination of moisture content in a deformable soil using time-domain reflectometry (TDR)

2000 ◽  
Vol 51 (1) ◽  
pp. 119-127 ◽  
Author(s):  
D. J. Kim ◽  
S. I. Choi ◽  
O. Ryszard ◽  
J. Feyen ◽  
H. S. Kim
Keyword(s):  
Moisture Content ◽  
Time Domain ◽  
Time Domain Reflectometry

Determination of Moisture Diffusivity using the Time Domain Reflectometry (TDR) Method

2006 ◽  
Vol 30 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Zbyšek Pavlík ◽  
Milena Jiřičková ◽  
Robert Černý ◽  
Henryk Sobczuk ◽  
Zbigniew Suchorab
Keyword(s):  
Time Domain ◽  
Moisture Diffusivity ◽  
Time Domain Reflectometry ◽  
The Time Domain

scholarly journals Steel-shot method for measuring the density of soils

2010 ◽  
Vol 47 (11) ◽  
pp. 1299-1304 ◽  
Author(s):  
Reed B. Freeman ◽  
Chad A. Gartrell ◽  
Lillian D. Wakeley ◽  
Ernest S. Berney ◽  
Julie R. Kelley
Keyword(s):  
Moisture Content ◽  
Rapid Determination ◽  
Content Volume ◽  
Test Method ◽  
Unit Weight ◽  
Soil Density ◽  
Engineering Construction ◽  
Steel Shot ◽  
Time Requirements

The density of soil is crucial in engineering, construction, and research. Standard methods to determine density use procedures, equipment or expendable materials that limit their effectiveness in challenging field conditions. Some methods require burdensome logistics or have time requirements that limit their use or the number of tests that can be executed. A test method, similar to the sand-cone method, was developed that uses steel shot as the material to which a volume of soil is compared to calculate soil density. Steel shot is easily recovered and reused, eliminating the need for specialty sand and calibrated cones or containers, and allows rapid determination of the volume of displaced soil. Excavated soil also provides measurements of total mass and moisture content. Volume, mass, and moisture content are applied in simple calculations to determine wet and dry densities and unit weight of the soil. Proficiency in performing the test can be achieved with minimal training, and the required kit can be assembled for a reasonable cost. Field uses of the method in dry environments in a variety of soil types demonstrated that the method can produce repeatable results within 2% of the values of soil density determined by traditional methods, with advantages in logistics.

scholarly journals CARACTERIZAÇÃO DA DISTRIBUIÇÃO DA ÁGUA NO SOLO PARA IRRIGAÇÃO POR GOTEJAMENTO

Irriga ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 564-577 ◽  
Author(s):  
Leonardo Do Nascimento Lopes ◽  
Elton Martins ◽  
Bruno De Lima Santoro ◽  
Claudinei Fonseca Souza
Keyword(s):  
Water Content ◽  
Time Domain ◽  
Water Distribution ◽  
Water Storage ◽  
Time Domain Reflectometry ◽  
Wetting Front ◽  
Applied Water ◽  
Flow Rates ◽  
Abstract Knowledge ◽  
The Time Domain

CARACTERIZAÇÃO DA DISTRIBUIÇÃO DA ÁGUA NO SOLO PARA IRRIGAÇÃO POR GOTEJAMENTO  Leonardo do Nascimento Lopes1; Elton Martins2; Bruno de Lima Santoro2; Claudinei Fonseca Souza31Universidade de Taubaté, Unitau, Taubaté, SP,  [email protected] Engenharia Civil e Ambiental, Universidade de Taubaté, Taubaté, Unitau, SP 3Departamento de Recursos Naturais e Proteção Ambiental, Universidade Federal São Carlos, São Carlos, SP  1 RESUMO O conhecimento da distribuição da água no solo é de grande importância para a agricultura, uma vez que a água é um dos fatores que mais influenciam o rendimento das culturas. Existem muitas técnicas utilizadas para o monitoramento do conteúdo de água do solo, a reflectometria domínio do tempo (TDR) tem sido difundida entre os pesquisadores por apresentar várias vantagens, entre as quais a determinação em tempo real e a possibilidade de leituras automatizadas. O principal objetivo desta pesquisa foi avaliar a distribuição da água no perfil de um Latossolo Vermelho-Amarelo. Sondas de Reflectometria no domínio do Tempo (TDR) foram utilizadas para monitorar a distribuição de água no solo aplicada através de gotejadores de fluxo constante nas taxas de 2, 4 e 8 Lh-1. Considerando os resultados de diferentes perfis, observa-se um maior armazenamento da água próximo do gotejador diminuindo progressivamente para frente de molhamento. Aproximadamente, um terço da água aplicada (33%) foi armazenado na primeira camada (0-0,10 m) para todos os ensaios. Comparando diferentes taxas de aplicação, observa-se maior armazenamento de água para o gotejador de 8L h-1, com 30, 33 e 34% de água aplicada acumulada na primeira camada (0-0.10 m) para gotejadores de 2, 4 e 8L h-1, respectivamente. Os resultados sugerem que, com base no volume e frequência utilizada neste experimento, seria vantajoso aplicar pequenas quantidades de água em intervalos mais frequentes para reduzir perdas por percolação. UNITERMOS: TDR, conteúdo de água, bulbo molhado  LOPES, L. N.; MARTINS, E.; SANTORO, B. L.; SOUZA, C. F.WATER DISTRIBUTION CHARACTERIZATION IN SOIL FOR DRIP IRRIGATION   2 ABSTRACT Knowledge of water distribution in soil is of great importance to agriculture, since water is one of the factors that most influence the yield of crops. There are many techniques used to monitor soil water content. The time domain reflectometry (TDR) has been widespread among researchers because it presents several advantages, among which the determination in real time and possibility of automated readings. The main goal of this research was to evaluatethe water distribution in a profile of Red-Yellow Oxisol. Time domain reflectometry (TDR) probes were used to monitor the water distribution from drippers discharging at constant flow rates of 2, 4 and 8 Lh-1 in soil. Considering results from different profiles, we observed greater water storage near the dripper decreasing gradually towards the wetting front. About one third of the applied water (33%) was stored in the first layer (0-0.10 m) for all experiments. Comparing different dripper flow rates, we observed higher water storage for 8 L h-1, with 30, 33 and 34% of applied water accumulating in the first layer (0-0.10m) for dripper flow rates of 2, 4 and 8 L h-1, respectively. The results suggest that based on the volume and frequency used in this experiment, it would be advantageous to apply small amounts of water at more frequent intervals to reduce deep percolation losses of applied water. KEYWORDS: TDR, water content, wetted soil volume

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