Probing pH Levels in Civil Engineering Materials

Vimer, Cristian S.; Yu, Siukei; Ghandehari, Masoud

doi:10.1061/(asce)0899-1561(2009)21:2(51)

Cited by 16 publications

(12 citation statements)

References 19 publications

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“…5–8 The efficiency and reliability of guided wave–based inspection techniques have been reported extensively in the literature. 9–13 Guided waves have some distinct advantages for monitoring large structures compared to other techniques, such as electromagnetic, optical, or chemical sensing techniques 14,15 for which the probes must be placed relatively close to the inspection region that is not necessary for guided wave–based inspection techniques.…”

Section: Introductionmentioning

confidence: 99%

Detection and quantification of diameter reduction due to corrosion in reinforcing steel bars

Amjad

Yadav

Kundu

2015

Structural Health Monitoring

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Guided wave–based techniques are becoming popular for damage detection in pipes, rods, and plates. For monitoring reinforced concrete beams, the longitudinal guided wave is excited and recorded after its transmission through the reinforcing steel bar for estimating its corrosion level. Recorded signal amplitude is affected by the corrosion level. Thus, the corrosion level is estimated from the transmitted wave amplitude. Instead of investigating the amplitude of the transmitted guided waves, the differential time-of-flight of the propagating wave modes is recorded in this article. The differential time-of-flight is obtained from the time–frequency representations of the recorded transient signals and from the high temporal resolution using the cross-correlation technique. It is observed that the corrosion level can be quantified from the change in time-of-flight of the L(0,1) mode. The guided wave modes are experimentally generated, recorded, and compared with the theoretical dispersion curves to identify different modes and select the most efficient mode for quantifying the corrosion level. Unlike the recorded signal strength, the time-of-flight is not influenced by the bonding condition between the sensors and the specimen; therefore, the time-of-flight-based corrosion-monitoring technique is less influenced by the sensor bonding condition. This investigation is necessary because most investigators have studied the effect of corrosion on the recorded signal strength instead of its time-of-flight.

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Section: Introductionmentioning

confidence: 99%

Detection and quantification of diameter reduction due to corrosion in reinforcing steel bars

Amjad

Yadav

Kundu

2015

Structural Health Monitoring

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“…The guided wave-based techniques have been found to be very efficient for damage detection and condition assessments of various aerospace and civil structures. One reason for the guided wave-based technique's popularity is that it can detect damages from relatively large distances unlike conventional electromagnetic, optical, or chemical sensing techniques 34,35 for which the probes must be placed relatively close to the inspection region. In spite of many applications of the guided wave-based techniques for damage detection, as some are referred above, in none of the earlier works the technique has been used in the same way as it is performed in this article.…”

Section: Introductionmentioning

confidence: 99%

A new guided wave–based technique for corrosion monitoring in reinforced concrete

Miller

Kundu

Huang

et al. 2012

Structural Health Monitoring

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Guided waves have been used in the past for monitoring corrosion and other damages in plates, rods, pipes, and reinforced concrete structures. Past investigations tried to relate the recorded signal strength to the extent of corrosion or other damage. The main disadvantage of this approach is that the signal strength is also affected by the bonding condition between the sensors and the structure. Over time, this bonding condition is bound to deteriorate, and therefore, one cannot say for sure if the change in the signal strength is due to corrosion or because of the deterioration of the attachment of the sensors to the structure. A new guided wave-based technique is proposed here, which investigates the change in the time of flight of the propagating wave in loaded reinforced concrete structures at various levels of corrosion. Corrosion affects the bonding strength between concrete and reinforcing steel altering the stress level in the reinforcing steel bar in a loaded beam. Since the wave speed is affected by the internal stress, an increase in corrosion level should affect the wave speed in a steel bar and the wave's time of flight through the bar. The main advantage of the proposed approach is that this result should not be affected by the bonding condition between the sensor and the structure. How delamination at the bar-concrete interface affects the signal strength and the effect of induced corrosion in free bars as well as in bars embedded in the concrete are also investigated.

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“…[20]. Due to the harsh condition of concrete in terms of the high pressure and high alkalinity condition, continuously measuring the pH value within concrete is always a very difficult task.…”

Section: Review On Ph Measurementmentioning

confidence: 99%

Monitoring Apparent pH Value in Geopolymer Concrete Using Glass Electrode

Jin¹,

Shen²,

Castel³

et al. 2016

Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC)

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-Geopolymer concrete (GPC) is estimated to reduce 80% carbon footprint in construction projects compared with ordinary Portland cement (OPC). Previous studies on GPC have been focusing on assessment of paste or mortar while the long-term durability of GPC has not been extensively investigated yet. This research aims to monitor carbonation process of GPC by measuring in-situ apparent pH value under accelerated carbonation test in laboratory environment. Glass pH electrode is typically applied for liquid medium and considered to be unsuitable for OPC due to high alkaline condition. We have endeavoured to test the glass electrode in GPC assuming the alkalinity in GPC would be much lower than OPC. Two pH probe sensors were embedded into GPC specimens with different depth and seal condition. After 18 hours heat cures and 7 days curing in ambient environment, one of GPC specimens was then relocated to a carbonation chamber with 1% carbon dioxide concentration. The glass electrodes were found to survive the GPC environment with realtime apparent pH value registered since the GPC specimens were poured. It is also observed that the apparent pH values were affected significantly by the level of humidity inside the concrete. Saturation experiments were then conducted to provide valid pH readings. As a result, we successfully monitored pH decreasing from 11.1 to 10.76 after three months carbonation experiment. The results are also validated by comparing against the data acquired by traditional concrete grinding test. The research features the first trial of its kind and has contributed to comprehensive understanding about corrosion mechanism of the new GPC material.

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Probing pH Levels in Civil Engineering Materials

Cited by 16 publications

References 19 publications

Detection and quantification of diameter reduction due to corrosion in reinforcing steel bars

Detection and quantification of diameter reduction due to corrosion in reinforcing steel bars

A new guided wave–based technique for corrosion monitoring in reinforced concrete

Monitoring Apparent pH Value in Geopolymer Concrete Using Glass Electrode

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