Inspection of concrete structures externally reinforced with FRP composites using active infrared thermography: A review

This paper provides a comprehensive review on the use of infrared thermography to detect delamination on infrastructures and buildings. Approximately 200 pieces of relevant literature were evaluated, and their findings were summarized. The factors affecting the accuracy and detectability of infrared thermography were consolidated and discussed. Necessary measures to effectively capture latent defects at the early stage of delamination before crack formation were investigated. The results of this study could be used as the benchmarks for setting standardized testing criteria as well as for comparison of results for future works on the use of infrared thermography for detection of delamination on infrastructures and buildings.

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A Review of Infrared Thermography for Delamination Detection on Infrastructures and Buildings

Tsunami modeling and simulation has changed in the past few years more than it has in decades, especially with respect to coastal inundation. Among other things, this change is supported by the approaching era of exa-scale computing, whether via GPU or more likely forms of hybrid computing whose presence is growing across the geosciences. For reasons identified in this review, exa-scale computing efforts will impact the on-shore, highly turbulent regime to a higher degree than the 2D shallow water equations used to model tsunami propagation in the open ocean. This short review describes the different approaches to tsunami modeling from generation to impact and underlines the limits of each model based on the flow regime. Moreover, from the perspective of a future comprehensive multi-scale modeling infrastructure to simulate a full tsunami, we underline the current challenges associated with this approach and review the few efforts that are currently underway to achieve this goal. A table of existing tsunami software packages is provided along with an open Github repository to allow developers and model users to update the table with additional models as they are published and help with model discoverability.

Modeling and Simulation of Tsunami Impact. a Short Review of Recent Advances and Future Challenges

Permeable concrete is a new type of pavement material, which can effectively improve the urban flood discharge system, and is of great significance to the construction of sponge city. In order to optimize the use effect of permeable concrete and improve the application value of permeable concrete in permeable road engineering, the combination of rubber aggregate and permeable concrete is proposed, and the mix ratio of rubber permeable concrete mixture material is designed, which is applied to the engineering of pavement in Hunan Province, and its comprehensive pavement performance is analyzed and evaluated. The results show that the rubber permeable concrete has the best performance when the water cement ratio is 0.3, the designed porosity is 15%, the rubber particle size is 16 mesh, the rubber content is 15% and the coarse aggregate ratio is 4:6. The removal rates of suspended solids and metal pollutants are 0.65 and 0.72, respectively, which are increased by 0.23 and 0.19, respectively, compared with ordinary permeable concrete. This shows that rubber permeable concrete improves the ecological benefits of permeable concrete pavement, gives full play to the economic benefits of waste rubber products, reduces the construction cost of permeable concrete pavement, and provides assistance for promoting the construction of sponge city.

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The Application of Rubber Aggregate-Combined Permeable Concrete Mixture in Sponge City Construction

Ultrasonic inspection of grouted splice sleeves in precast concrete structures using elastic reverse time migration method

Two different techniques for ultrasonic imaging of concrete are presented, namely a weighted sum technique and a statistical technique. The techniques utilize both the scattered elastic compressional and the mode converted shear wave fields. Since the conventional imaging techniques utilize either the compressional or the shear wave mode to generate the subsurface image, information contained in the scattered ultrasonic field is partially utilized. The proposed techniques intend to use more information contained in the scattered field leading to an improvement in the final image. Synthetic full matrix data is generated using the finite difference in time domain scheme for simulation of elastic wave propagation in concrete with embedded rebars and aggregates. The proposed imaging techniques are then used to generate the subsurface image of the medium. Experiments were also performed to generate full matrix data on two concrete slabs with different geometry, sizes and distribution of rebars. The applicability of the proposed imaging techniques is demonstrated on the experimentally acquired data. The images when compared to the ones generated by the conventional single mode approach, show improvement in resolution and distinction between the embedded features, e.g. closely spaced rebars. It is also observed that the weighted sum technique performs slightly better in comparison to the statistical technique with respect to suppression of background noise.

Ultrasonic imaging of concrete using scattered elastic wave modes

Corrosion of reinforcement in concrete is a billion dollar problem spread across the globe. Early detection of corrosion-induced damage preempts weakening of the structure and timely rehabi...

Nondestructive Evaluation of Rebar Corrosion–Induced Damage in Concrete through Ultrasonic Imaging

Reference free imaging of subsurface cracks in concrete using Rayleigh waves

The estimation of wave pressure on structures is complex during tsunami due to its unpredictable velocity and direction which depends on various ocean parameters. In this context, some tsunami mitigation strategy can be adopted, so that damage to structures during tsunami may be minimized. The effectiveness of different opening sizes in buildings to reduce wave pressure is investigated numerically in the present study. These results may also be applicable to simulate the tsunami impact on breakaway wall of a building. The effectiveness in tsunami force reduction is quantified in terms of pressure reduction throughout the building height. Computational fluid dynamics technique is used to analyze the wave impact on buildings. Solitary wave is generated in numerical platform by controlling discharge in a channel inlet. Three-dimensional Reynolds Averaged Navier–Stokes model is used to solve the governing equitation of fluid flow. Realizable k–ɛ turbulence model is applied for turbulence modeling. Multiphase ...

https://journals.sagepub.com/doi/pdf/10.1177/0010836716653881

Debdutta Ghosh

Papers

Inspection of concrete structures externally reinforced with FRP composites using active infrared thermography: A review

Ultrasonic imaging of concrete using scattered elastic wave modes

Nondestructive Evaluation of Rebar Corrosion–Induced Damage in Concrete through Ultrasonic Imaging

Reference free imaging of subsurface cracks in concrete using Rayleigh waves

Multiphase modeling of tsunami impact on building with openings