Department of Civil Engineering

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Management of bridge assets requires a life-cycle approach that balances design and construction of new bridges, and maintenance of existing bridge stock. There has been a growing need for inspection, maintenance, repair, and strengthening of existing bridge structures due to aging transportation infrastructure. Condition assessment of post-tensioning systems could allow bridge owners to take timely, proactive actions to mitigate or prevent further deterioration and unanticipated failure. An experimental study to evaluate various nondestructive evaluation (NDE) techniques for the condition assessment of grout defects in external post-tensioning systems is presented. To evaluate the NDE technologies, a full-scale post-tensioned girder specimen was constructed at the Texas A&M University RELLIS Campus. Several grout defects including voids, water infiltration, and compromised grout were fabricated and placed in the specimen for the evaluation of the NDE methods. The research team, in collaboration with several industry partners, used various NDE technologies, such as sounding, impact echo, low-frequency ultrasound, ground-penetrating radar, infrared thermography, and electrical capacitance tomography, to evaluate the grout condition of the external tendons of the post-tensioned girder specimen. Comparison of the test results with the actual defects revealed the performance of each method in detecting the location and the severity of the various grout defects in the external tendons of the post-tensioning system. © 2018 American Society of Civil Engineers.

World University root node

Journal of Structural Engineering (United States)

Nondestructive Evaluation of External Post-Tensioning Systems to Detect Grout Defects

Nondestructive evaluation (NDE) can provide invaluable information about the condition of tendons in post-Tensioned and cable-stayed bridges, which can facilitate preventative actions to mitigate further deterioration. To date, the use of nondestructive testing methods for routine maintenance of bridges has been relatively low, partly due to limitations of available technologies but mainly owing to a lack of know-how regarding existing NDE techniques and guidelines. This study aims to develop guidelines to assist bridge owners and engineers in selecting the most appropriate NDE method or combination of methods for assessing the condition of in-service post-Tensioning and stay cable systems. An extensive experimental study is conducted on a full-scale post-Tensioned girder specimen and four large-scale stay cable specimens to evaluate the performance of various NDE methods in detecting location and severity of numerous strand and grout defects. Decision metrics are developed considering multiple criteria such as precision, accuracy, ease of use, inspection requirements, and cost. The decision metrics are intended to facilitate selecting the most appropriate NDE method for assessing a particular defect condition. Overall scores for the tested NDE methods in identifying various defect conditions in different parts of the post-Tensioning and stay cable systems are calculated using a weighted sum model. These scores are used to develop a list of ranked NDE methods for evaluating a particular defect condition within a specific location and for a specific duct material. © 2019 American Society of Civil Engineers.

Journal of Infrastructure Systems

Systematic Assessment of Nondestructive Evaluation Techniques for Post-Tensioning and Stay Cable Systems

The influence of geomembrane in maintaining the sealing efficiency of a landfill cover system at the onset of flexural distress was studied by conducting a series of centrifuge tests performed at 40 gravities. The tests were performed using a 4.5 m radius beam centrifuge having a capacity of 2,500 g-kN available at IIT Bombay on model composite barriers of 0.6 m thickness. The thickness and tensile stiffness of the geomembrane were varied. All the models were instrumented with pore pressure transducers (PPTs), linear variable differential transformers (LVDTs), a digital camera and a charge-coupled device (CCD) video camera to study the performance of the barriers during centrifuge tests. The sealing efficiency of the composite barriers was found to be maintained even after the formation of full-depth cracks within 0.6 m thick clay barriers subjected to a maximum distortion level of 0.125. This observed behaviour is attributed to the downward thrust exerted by the deformed geomembrane at the zone of maximum curvature which hinders the infiltration of water through the cracks. The downward thrust exerted by the geomembrane on the clay barrier was found to be more for barriers provided with stiffer and thicker geomembrane. © Springer Nature Singapore Pte Ltd 2019.

Lecture Notes in Civil Engineering

Influence of geomembrane stiffness on the integrity of landfill covers: Centrifuge modelling

Bentonite was added to a locally available rock dust to study the behaviour thresholds of the binary mix. Thresholds may be defined as the critical fines content above which the system behaviour changes drastically. By understanding the threshold values of such binary mixtures will help us to have a better control over its behaviour. In this study, the hydraulic conductivity and the swelling behaviour of quarry dust mixed with increasing fractions of bentonite were studied. Index properties of quarry dust were determined by standard sieve analysis, mini-compaction and by cone penetration method. The specific gravity of the quarry dust was about 2.65. The addition of bentonite to quarry dust has found to increase the maximum dry density and reduce the hydraulic conductivity by several orders. The swell potential of the various mix proportions was studied in an oedometer. Samples were of 14 mm thickness and were given a hydration period of 24 h and were compacted at their OMC and MDD. Mixes with low bentonite contents such as a 5% and 10% showed no swelling. The substantial swelling was only observed with 15% bentonite and more. © Springer Nature Singapore Pte Ltd 2019.

Behaviour thresholds of quarry dust–bentonite mixes

Industrial flooring is an emerging application of modern concrete construction. It is widely acknowledged and carried out in several developed countries with proper guidelines and specifications. The rapid expansion in the infrastructure as well as industries in developing countries like India have increased the demand for better quality floors, increasing the overall attention towards the concrete floor standards. However, a dedicated standard for industrial concrete flooring including proper specifications, practice guidelines and modern techniques is not available in India. In the present study, various requirements of the industrial concrete floor have been reviewed with respect to the available major international standards and specifications. Furthermore, recent improvements in technology and innovative materials related to industrial concrete flooring are incorporated. From the comprehensive review, it was observed that the flatness criteria, slip resistance, chemical and crack resistance are some of the major parameters that need to be specified for an industrial concrete floor. Moreover, specifications for concrete flooring are found to vary with respect to the type of industry. Recommendations to Indian standards based on international standards, advanced technologies and practices are highlighted to achieve high quality industrial concrete flooring in the Indian context. © 2019 Associated Cement Companies Ltd.. All rights reserved.

Indian Concrete Journal

Internat ional perspectives on industrial concrete flooring and the way forward in India

This study investigated the cracking mechanism of Asphalt-Rubber Gap-graded (AR-Gap) mixtures with various material properties. The research focused on using a monotonic semicircular bending (SCB) test to estimate the cracking potential of AR-Gap mixtures at 0°C and 25°C. A total of 28 asphalt mixtures, including 27 AR-Gap mixtures and 1 conventional dense-graded (DG) mix, covering over 220 data points were utilized for evaluation. The outcome parameter, fracture toughness, KIC, calculated from the SCB test was used to compare and contrast the mixtures’ resistance to cracking at low and intermediate temperatures. At both test temperatures, the results indicated that AR-Gap mixtures have higher fracture resistance (~60 %) than the DG mix. Furthermore, statistical analyses confirmed that asphalt binder type, aggregate gradation, and binder content had significant effects on cracking performance. Aggregate gradation had a more pronounced effect on cracking performance than binder type, followed by binder content. In addition, a KIC predictive model was developed that had excellent statistical goodness-of-fit measures (R2 ≥ 90 %), which can be conveniently utilized in case of unavailability of the test setup. Overall, the findings revealed superior performance characteristics of AR-Gap mixtures that had high potential to resist cracking. Based on the various outcomes, the study was able to recommend aggregate gradation, binder type, and binder content as the parameters that would exhibit higher resistance against cracking failure. It is envisaged that this research would further the state of the art in designing crack-resistant asphalt mixtures. © 2019 by ASTM International.

Journal of Testing and Evaluation

Investigation of cracking performance of asphalt-rubber gap-graded mixtures: Statistical overview on materials’ interface

This study evaluated the performance of asphalt-rubber gap-graded (AR-Gap) mixtures under various test conditions and established a novel design toolkit that was proficient to rank the mixtures, which helped recommend the best performing material. A total of 28 asphalt mixtures, including, one dense-graded and 27 AR-Gap mixtures were considered. Euclidean distance approach was utilized to determine the best AR-Gap mixture based on ten pavement material design parameters. It is envisaged that this toolkit will help researchers and practitioners to prioritize the desired combinations of asphalt mixture materials properties, thereby assisting in selection of best performing pavement system for field implementation. © 2019 Elsevier Ltd

Construction and Building Materials

A novel design toolkit to assess asphalt-rubber gap-graded mixture performance: Target properties and parametric relationships

Creative Construction Conference

Process Reengineering using Activity Theory and Domain Mapping Matrix Method in Delivering Public Construction Projects

A construction project is subjected to unique complexities that increase the probability of risk occurrence and adversely impact the achievement of the project objectives. Studies have shown that risks should be managed as early as possible in the project's life cycle, especially during the design phase. In doing so, key challenges arise from the fact that modern design process is inherently iterative in nature. Thus, the management of information exchange forms the basis for achieving the desired project objectives. Many tools and methods have been developed to manage the information exchange in design projects. However, Building Information Modeling (BIM) is one of the most widely used phenomena in the UAE's high-rise building projects. Though the adoption improves the overall project delivery, its application in the risk management of these projects is not widespread. Hence, this research aims to contribute in developing a risk management framework for the BIM-enabled design by identifying the key design phase related risks impacting the time of the projects. An interviews were conducted and the preliminary results identified the top 10 risks impact the time of the projects in the UAE. Further, the paper mapped the identified most significant risks against its possible BIM based solutions. © IEOM Society International.