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

In most agricultural systems, the raindrop-induced breakdown of soil aggregates is the initial process of surface soil erosion and redistribution of soil organic matter. The physicochemical differences between the liberated and mobilized material and the residual raindrop-stable soil aggregates can be a critical factor controlling landscape-level heterogeneity in soil biogeochemical reactivity. Using an artificial rainfall simulator with soils from southeastern Iowa, we investigated the role of management intensity on the chemical characteristics of soil particles liberated through raindrop-induced breakdown of both small aggregates (0.25–2 mm; SMAGG) and large aggregates (&gt;2 mm; LGAGG). At all sites LGAGG exhibited lower stability to raindrop energy than SMAGG. Both soil aggregate size classes from a restored prairie and an agricultural site using reduced ridge tillage exhibited higher raindrop stability than conventionally tilled sites. In the restored prairie, the chemical composition (i.e. lignin, substituted fatty acids, SOC and TN, δ15N values) of raindrop-liberated particles was nearly indistinguishable from raindrop-stable aggregates. Among all tilled sites, with the exception of SOC in the conservation tillage site, the raindrop stable particles had relatively higher concentration of measured chemical components versus raindrop-liberated particles. Additionally, the liberated particles in all tilled sites contained higher concentration of oxidized lignin phenols, a lower proportion of cinnamyl to vanillyl lignin, and, as evidenced by the δ15N values, a trend toward a higher proportion of microbially-processed nitrogen, indicating more decomposed microbial processed organic matter. These results are important for understanding the biogeochemical impacts and resulting spatial heterogeneity of raindrop liberated and transported soil particles among landscapes with different management intensity and efforts toward soil conservation. © 2018

World University root node

Geoderma

Control of tillage disturbance on the chemistry and proportion of raindrop-liberated particles from soil aggregates

Post-tensioning systems provide safe and efficient construction solutions for long span bridges. Despite the improved grouting practices over the past decade, existing post-tensioning systems may have significant amount of grout defects, which could lead to corrosion of the strands. Condition assessment of post-tensioning systems is necessary to allow bridge owners to take timely, proactive actions to mitigate or prevent further deterioration and unanticipated tendon failures. A detailed experimental study conducted to assess the performance of nondestructive evaluation techniques in detecting grout defects within internal tendons is presented herein. Nondestructive evaluation techniques that include Ground Penetrating Radar, Impact Echo, Ultrasonic Tomography, and Ultrasonic Echo are evaluated in terms of detecting the location and severity of fabricated grout defects in a full-scale post-tensioned U-girder mock-up specimen. While Ground Penetrating Radar can identify the location and profile of the internal tendons, particularly metal ducts due to strong reflections, this method did not provide any information about the defect conditions within the tendon. Both Impact Echo and Ultrasonic Echo techniques are effective in identifying the location of grout defects, but could not differentiate between water, void, or compromised grout conditions. The study clearly demonstrates the need for NDE techniques that are applicable to anchorage regions, and that are capable of estimating the severity and nature of grout defects in internal tendons. © 2018

NDT and E International

Nondestructive evaluation of grout defects in internal tendons of post-tensioned girders

Transportation Research Board 97th Annual MeetingTransportation Research Board

Nondestructive Evaluation of Stay Cable Specimens for Non-Strand Defects

The objective was to investigate the rheological and thermo-chemical behavior of asphalt-rubber (AR) binders and to evaluate the effect of various parameters on AR binder performance. The effort encompassed binder consistency, rheological, thermogravimetric, and Fourier transform infrared spectroscopy analyses of twelve different asphalts. It was found that CR inclusions not only improved the physical characteristics but also influenced the chemical and thermal properties of asphalt binder. Furthermore, it was inferred that employing higher CR dosages and fine CR gradations in asphalt binder will aid in producing an outstanding AR binder capable of performing well under extreme traffic and environmental conditions. © 2018 Elsevier Ltd

Construction and Building Materials

Investigations on behavioral characteristics of asphalt binder with crumb rubber modification: Rheological and thermo-chemical approach

10th Asian Rock Mechanics SymposiumAt: Singapore

Strength Behaviour of Anisotropic Rock Under True Triaxial Stress State

Long-term behavior of a granular material under repeated loading plays a vital role to understand the behavior of rutting in pavements. Many researchers observed the behavior of permanent strain accumulation in the granular material under cyclic loading condition. The permanent deformation of granular material caused by numerous factors varies with the degree of each factor influence on granular material. This paper summarizes and discusses the impact of individual factors on permanent deformation of granular material through reference to published scientific data. As well, this paper outlines the different constitutive models to find the permanent strain and discusses the permanent strain modelling using shakedown theory. © 2018, Indian Journal of Public Health Research and Development. All rights reserved.

Indian Journal of Public Health Research and Development

A review on permanent deformation of granular material

The study makes a probabilistic assessment of drought risks due to climate change over the southeast USA based on 15 Global Circulation Model (GCM) simulations and two emission scenarios. The effects of climate change on drought characteristics such as drought intensity, frequency, areal extent, and duration are investigated using the seasonal and continuous standard precipitation index (SPI) and the standard evapotranspiration index (SPEI). The GCM data are divided into four time periods namely Historical (1961–1990), Near (2010–2039), Mid (2040–2069), and Late (2070–2099), and significant differences between historical and future time periods are quantified using the mapping model agreement technique. Further, the kernel density estimation approach is used to derive a novel probability-based severity-area-frequency (PBS) curve for the study domain. Analysis suggests that future increases in temperature and evapotranspiration will outstrip increases in precipitation and significantly affect future droughts over the study domain. Seasonal drought analysis suggest that the summer season will be impacted the most based on SPI and SPEI. Projections based on SPI follow precipitation patterns and fewer GCMs agree on SPI and the direction of change compared to the SPEI. Long-term and extreme drought events are projected to be affected more than short-term and moderate ones. Based on an analysis of PBS curves, especially based on SPEI, droughts are projected to become more severe in the future. The development of PBS curves is a novel feature in this study and will provide policymakers with important tools for analyzing future drought risks, vulnerabilities and help build drought resilience. The PBS curves can be replicated for studies around the world for drought assessment under climate change. © 2018, Springer Science+Business Media B.V., part of Springer Nature.

Climatic Change

Probabilistic assessment of projected climatological drought characteristics over the Southeast USA

SWAT Conference

Uncertainty in the SWAT Model Simulations due to Different Spatial Resolution of Gridded Precipitation Data

This study presents the outcome of an experimental evaluation of a structure isolated by flat sliding bearing with nonlinear restoring springs. The composite device of flat sliding bearing with nonlinear stiffening springs, which has been proposed recently, has the following advantages: (i) its behavior is similar to that of flat sliding bearing for minor to moderate level of shaking, (ii) for high intensity shaking, the device reduces the peak bearing displacement in comparison to the flat sliding bearing, and (iii) the device minimizes the bearing residual displacement irrespective of intensity of shaking. The experimental study conducted with a steel moment-resisting frame demonstrates that the device is quite effective in reducing the peak and residual bearing displacements. Further, it is found that other parameters such as peak inter-story drift and peak horizontal floor acceleration are not significantly affected by addition of restoring springs. Hence, the proposed system is an ideal candidate for a cost-effective base isolation system. © 2017 Elsevier Ltd

Engineering Structures

Seismic response control of a structure isolated by flat sliding bearing and nonlinear restoring spring: Experimental study for performance evaluation

Slight and moderate amounts of deterioration caused by alkali silica reaction (ASR)/delayed ettringite formation (DEF)-induced expansion in reinforced concrete specimens do not markedly or detrimentally affect its structural load-carrying capacity. However, effects of severe (late-stage) ASR/DEF deterioration on the load-carrying capacity of structures is not known. A large-scale reinforced concrete C-beam specimen with heavy ASR/DEF deterioration is load tested in the laboratory. A comparison of the force-deformation results of the severely deteriorated specimen with the undamaged control specimen, and slightly and moderately ASR/DEF-deteriorated specimens, shows that there is no reduction in the load-carrying capacity. The mode of failure of the specimen is a brittle joint-shear failure similar to the other C-beam specimens. However, a reduction in the ductility of the heavily deteriorated specimen is observed. Postfailure examination shows a significant degree of corrosion in the longitudinal and transverse reinforcement. Significant bulging and complete debonding of the lapped transverse U-bars in the specimen knee-joint caused considerable loss in confinement of the softened concrete, resulting in an embrittled performance and sudden early loss of load in the heavily damaged specimen. It is not known how further corrosion in conjunction with severe ASR/DEF deterioration could affect the future behavior of the structure. © 2018 American Society of Civil Engineers.