GWT – New Testing System for “in-situ” Measurements of Concrete Water Permeability

Moczko, Andrzej; Moczko, Marta

doi:10.1016/j.proeng.2016.08.162

Cited by 15 publications

(7 citation statements)

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“…According to Andrzej and Marta ( 24 ) the average water flux measured is not more than 0.32 μm/s. Based on the regression analysis in this study, this value corresponds to a bulk conductivity of 0.194 mS/m and surface conductivity of 0.105 mS/m.…”

Section: Results and Analysismentioning

confidence: 94%

“…Thus, it can be assumed that RAC can achieve low water permeability by lowering the water/cement ratio of the concrete mixture. It is important to note that the referenced study ( 24 ) performed the tests in concretes from road bridges which were likely made from natural aggregates. The equivalent water flux for a 50 mm water penetration on natural aggregate concrete might be different than 100% RCA concrete.…”

Section: Results and Analysismentioning

confidence: 99%

“…While there are no formal requirements for the maximum water penetration in concrete for practical applications, concrete can be evaluated as water-resistant when the average maximum depth of water penetration measured is not higher than 50 mm ( 24 ). Based on an established correlation ( 24 ) between the GWT and BS EN 12390-8 standard, the 50 mm depth in the 72 h water penetration test corresponds to a 10 min average water flux of 0.32 μm/s.…”

Section: Methodsmentioning

confidence: 99%

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Correlation of Electrical Resistivity and Formation Factor with Chloride and Water Permeability of Recycled Aggregate Concrete

Aragoncillo

Lomboy

2022

Transportation Research Record

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Among the methods of determining the permeability of concrete, electrical resistivity tests are the most rapid and one of the simplest techniques. Several studies have found a strong correlation between electrical resistivity and the other permeation properties, such as water permeability and rapid chloride penetrability. However, most of these comparisons used conventional concrete in which natural aggregates were used. Concrete with alternative aggregates such as recycled aggregate concrete (RAC) shows a different microstructure and higher permeability than conventional concrete. Thus, the existing correlations might not be applicable for concrete with recycled aggregates. This research measures the electrical resistivity (AASHTO T 358 & AASHTO TP 119), formation factor, rapid chloride permeability (ASTM C 1202), and water permeability (Germann water permeability test: GWT) of RAC. High chloride ion permeability was observed in all the samples. On the other hand, some samples were found to have low water permeability. It was observed that RAC could be evaluated as water-resistant when a low water/cement ratio was used. The bulk resistivity, surface resistivity, and formation factor were all found to be strongly correlated with rapid chloride permeability test and GWT measurements. Compared with the established correlation from other studies using conventional concrete, RAC shows a higher slope of electrical resistivity versus chloride permeability regression line. On the other hand, RAC can be assumed to have low water permeability when the bulk resistivity, surface resistivity, and formation factor are greater than 5.2 kΩ-cm, 9.6 kΩ-cm, and 528, respectively.

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Section: Results and Analysismentioning

confidence: 94%

Section: Results and Analysismentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Correlation of Electrical Resistivity and Formation Factor with Chloride and Water Permeability of Recycled Aggregate Concrete

Aragoncillo

Lomboy

2022

Transportation Research Record

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“…Usually, a single test takes about 5-10 minutes, according to the quality of concrete (Andrzej and Marta, 2016).…”

Section: Durability Properties (Permeability Test)mentioning

confidence: 99%

Sustainable Repairing and Improvement of Concrete Properties Using Bacterial Consortium Isolated From Egypt

Mahmoud¹,

Kalaba

El-Sherbiny

et al. 2021

Preprint

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The small cracks in concrete constructions are inevitable due to deterioration during their service life throughout different load combination factors. In this study, we aimed to isolate, identify, and construct a bacterial consortium able to heal small cracks of concrete and enhance the different properties of concrete. Six isolates of bacillus, endospore-forming bacteria were isolated. There are only three isolates out of the six coded as NW-1, MK and NW-9 were showed the ability to produce urease enzyme and able to grow at 60°C with optimum growth at a temperature of 40°C. These isolates were survived in high pH, where isolate NW-1 was tolerated pH up to 11 with optimum growth at 10 while the isolates NW-9 and MK showed growth at pH 12 with an ideal growth at 10. CaCO3 production was observed by the three bacterial isolates whether in pure or mixed cultures (bacterial consortium) but the consortium consisting of MK and NW-9 was significantly the highest in productivity among them. Therefore, these two isolates were identified using 16s as Bacillus flexus MK-FYT-3 and Bacillus haynesii MK-NW-9 and deposited to GenBank under accession numbers MN965692 and MN965693 respectively. The effect of bacteria on some properties of concrete was studied, and the results showed that the compressive and tensile strengths of bio-concrete specimens were significantly increased by 31.29, 29 % after 7 days and 36.3, 39 % after 28 days of curing compared to control specimens. The results of permeability indicated that the bio-concrete specimens significantly showed less permeability than the control specimens by 21.1, 23.1% after 7 and 28 of curing, respectively. To determine the concrete density, Ultrasonic Pulse Velocity (UPV) test was performed, and the bio-concrete specimens gave higher values than control specimens by 26 and 20% after curing for 7 and 28 days, respectively. Also, surface healing of concrete was observed visually, the bio-concrete showed white precipitates around and inside the cracks after 7 days, which led to almost complete sealing of concrete after 28 days of curing, while the control samples were showed only very slight deposits on the surface and away from the cracks. The micro-analysis of concrete samples using SEM and XRD were done. It was found that the bio-concrete specimens showed crystalline precipitate with different shapes under SEM, while no such deposits appeared in the control specimens. On the other hand, the XRD profile was explained the characteristic peaks of calcium carbonate in both the bio-concrete and the control specimens, but the peak intensity was higher in the bio-concrete than the control specimens. This reflects the effectiveness of bacterial consortium in repairing and preventing the concrete cracks from spreading in addition to improving the various properties of concrete leading to increasing its life and sustainability.

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“…For the moisture measurement of concrete, a dielectric hygrometer or the like, which can detect changes in capacitance, is used. (4,5) However, this is a measurement of the moisture condition of only the surface part. Furthermore, in industrial production, it is important to measure the water condition in order to maintain the quality of food, which has become of prominent importance in recent years.…”

Section: Introductionmentioning

confidence: 99%

Pursuing a Possibility of Fabricating Moisture Measurement Devices Using Microwaves Passing through Materials ?Proposition of Measuring Quantity of Water Level Using Microwaves Passing through the Water Tank as the First Step of Development?

Akimoto¹,

Maruyama²,

Miyagawa³

et al. 2019

Sensors and Materials

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In recent years, an increasing number of sensors are being required in various industrial or automated production techniques. In particular, the need for moisture measurement is high, but a noncontact high-precision moisture sensor has not been put to practical use. Therefore, in this research, we focused on a moisture sensor that transmits microwaves and tested two methods for evaluation and verification. In the experiment, the water in the water tank was measured using radio waves of 2.4 GHz. As a result, although measurement could not be performed with high accuracy using the received signal strength, measurement using the propagation delay time was highly accurate. This result will provide an index for the application of moisture sensors using microwaves in the future.

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GWT – New Testing System for “in-situ” Measurements of Concrete Water Permeability

Cited by 15 publications

References 0 publications

Correlation of Electrical Resistivity and Formation Factor with Chloride and Water Permeability of Recycled Aggregate Concrete

Correlation of Electrical Resistivity and Formation Factor with Chloride and Water Permeability of Recycled Aggregate Concrete

Sustainable Repairing and Improvement of Concrete Properties Using Bacterial Consortium Isolated From Egypt

Pursuing a Possibility of Fabricating Moisture Measurement Devices Using Microwaves Passing through Materials ?Proposition of Measuring Quantity of Water Level Using Microwaves Passing through the Water Tank as the First Step of Development?

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