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

The validity of some of the assumptions made during systematic development of constitutive relation – homogeneity, isotropy, and non-dissipative response – is examined experimentally by testing plain concrete cylinders in the circumferential displacement controlled uniaxial compression tests. The tested cylinders indicate that the surface strains are not uniform and that the principal direction of the strain varies with the magnitude of the applied load. Hence, these cylinders are either deforming from a stressed state or anisotropic or both. The percentage dissipation computed as the area between the loading and unloading curves normalized using the area under the unloading curve is less than 10 percent up to 90 percent of the peak load. Therefore the mechanical response of concrete can be considered as non-dissipative. Assuming that the magnitude of the residual stresses present in the concrete panels would be small compared to the stresses arising due to the applied load, these residual stresses are ignored. Consequently, using the implicit constitutive theory framework for isotropic and compressible materials undergoing a non-dissipative process from a stress-free reference configuration, a three-dimensional constitutive relation for plain concrete is proposed. The material parameters in the proposed model are estimated from the uniaxial compression test and equal biaxial compression test. These parameters are expressed using initial Young's modulus, initial Poisson's ratio, maximum uniaxial compressive stress, the axial and transverse strain corresponding to the maximum uniaxial compressive stress, maximum equal biaxial compressive stress and the equal biaxial strain corresponding to maximum equal biaxial compressive stress. The ability of the proposed model to capture the response of various grade and type of concrete in ten biaxial experiments reported in the literature is examined. It is found that despite the limiting assumptions, the compression-compression, compression-tension and tension-tension stress strain response of the concrete in these ten experiments are adequately captured by the proposed model with mean R 2 value of 0.94. © 2019 Elsevier Ltd

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Construction and Building Materials

A three dimensional constitutive model for plain cement concrete

The objective of this research study was to evaluate the performance of Reacted and Activated Rubber (RAR) modified gap-graded asphalt mixtures, and compare the results with gap-graded asphalt mixtures modified with crumb rubber prepared through the dry mixing process. Further, the performance characteristics were compared with those of the RAR dense-graded asphalt mixtures. The scope of the study included conducting performance tests on RAR gap-graded mixtures, namely: resilient modulus test at various temperature-frequency combinations for initial stiffness evaluation; Indirect Tensile Fatigue Test for fatigue characterization; and Tensile Strength Ratio test for moisture sensitivity. Based on this research study, it was understood that RAR is a promising modifier for use in asphalt mixtures, which not only improves the strength properties, but also enhances the elastic behavior of the modified mixtures. Further, RAR content of 3% by weight of the total mixture is recommended as the optimum RAR dosage with gap aggregate gradation. It is envisioned that this study will help provide essential understanding towards the application of RAR gap-graded asphalt mixtures as superior performing pavements that are anticipated to outperform dense-graded asphalt mixtures, including RAR dense mix. &nbsp;

Rubberized Asphalt Rubber (RAR) 2018

Performance Characterization of Reacted and Activated Rubber Modified Gap Graded Asphalt Mixtures

International Conference on Desalination (InDACON-2018)

Efficiency in Chromium removal from metal plating industry effluent by Electrodialysis

The strength of thin-walled cold formed steel (CFS) lipped channel compression members may be governed by yielding, local, distortional, or global buckling or any possible interaction among these buckling modes. The interaction between buckling modes reduces the strength of thin-walled members to values below its strengths as affected by any one of the independent buckling modes. The direct strength method (DSM), which significantly simplified the evaluation of design strength of CFS members, recognizes this reduction in strength caused by interaction of buckling modes, but explicitly handles local-global interaction only. A simple and accurate interaction equation that accounts for interaction between all possible buckling failure modes for CFS lipped channel compression members is proposed in this paper. The method requires the use of modified DSM equations for evaluating the strength under the different independent buckling modes (local and distortional). The proposed interaction equation is validated with both experimental as well as numerical results.

Interaction of local, distortional and overall buckling in cold formed steel lipped channel compression members

IRF Global Road2Tunnel Conference, Las Vegas

Mechanistic Performance Prediction of Flexible Pavements at Varying Vehicular Speeds: An Approach to Address Frequency Singularity

Calcium carbide residue and fly ash are industrial by-products from acetylene gas industry and thermal power stations. Pavement construction has been recognized as a platform to utilize huge quantities of these waste materials for soil stabilization. An attempt has been made, in this paper, to evaluate the potential of a binder that consists of calcium carbide residue and fly ash to improve the engineering behavior of an expansive soil. The role of curing period and different percentages of these binder contents on Atterberg limits, compaction characteristics, strength, and mineralogical and morphological behavior has been examined. The index properties such as Atterberg limits and compaction characteristics have improved considerably. Significant improvement in the strength properties such as unconfined compressive strength and California bearing ratio has been observed with the addition of calcium carbide residue up to 8%. The binder content prepared with 10% calcium carbide residue and 6% fly ash obtained 18-fold enhancement in California Bearing Ratio (CBR) value and 16-fold enhancement in unconfined compressive strength (UCS). This is attributed to the formation of calcium based minerals formed as a result of a chemical reaction between the soil and binder, which were evidenced from mineralogical and morphological studies. From this experimental investigation, it can be concluded that the binder prepared with calcium carbide residue and fly ash is well suited for stabilization of expansive soils. © 2018 University of Kuwait. All rights reserved.

Journal of Engineering Research

Multi-scale laboratory investigation on black cotton soils stabilized with calcium carbide residue and fly ash

The physically based distributed hydrological models are ideal for hydrological simulations; however most of such models do not use the basic equations pertaining to mass, energy and momentum conservation, to represent the physics of the process. This is plausibly due to the lack of complete understanding of the hydrological process. The soil and water assessment tool (SWAT) is one such widely accepted semi-distributed, conceptual hydrological model used for water resources planning. However, the over-parameterization, difficulty in its calibration process and the uncertainty associated with predictions make its applications skeptical. This study considers assessing the predictive uncertainty associated with distributed hydrological models. The existing methods for uncertainty estimation demand high computational time and therefore make them challenging to apply on complex hydrological models. The proposed approach employs the concepts of generalized likelihood uncertainty estimation (GLUE) in an iterative procedure by starting with an assumed prior probability distribution of parameters, and by using mutual information (MI) index for sampling the behavioral parameter set. The distributions are conditioned on the observed information through successive cycles of simulations. During each cycle of simulation, MI is used in conjunction with Markov Chain Monte Carlo procedure to sample the parameter sets so as to increase the number of behavioral sets, which in turn helps reduce the number of cycles/simulations for the analysis. The method is demonstrated through a case study of SWAT model in Illinois River basin in the USA. A comparison of the proposed method with GLUE indicates that the computational requirement of uncertainty analysis is considerably reduced in the proposed approach. It is also noted that the model prediction band, derived using the proposed method, is more effective compared to that derived using the other methods considered in this study. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

Stochastic Environmental Research and Risk Assessment

A computationally efficient method for uncertainty analysis of SWAT model simulations

88th Annual Session of The National Academy of Sciences, India

IMPORTANCE OF STRENGTH ANISOTROPY IN NUMERICAL ANALYSIS

Climate and hydrologic variables such as temperature, precipitation, streamflow, and baseflow generally do not follow Gaussian distribution due to the presence of outliers and heavy tails. Therefore, they are usually analyzed using the nonparametric Wilcoxon rank sum test rather than parametric methods like classical t tests and analysis of variance. Furthermore, in addition to having a non-Gaussian distribution, these data exhibit monthly/seasonal variability, which leads to within month/season cluster correlation. In this study, a nonparametric procedure, called joint rank fit (JRFit), for analyzing cluster-correlated data was implemented and compared against traditional methods such as restricted maximum likelihood, least absolute deviations, and rank-based fit (a model-based extension of Wilcoxon rank sum) for studying the coupled effect of the phases of El Niño–Southern Oscillation and Atlantic Multidecadal Oscillation on baseflow levels. The results from a large Monte Carlo simulation experiment showed that JRFit was more efficient than the other three methods for data with (i) high variability, (ii) outliers due to contamination, or (iii) strong monthly/seasonal correlation. The efficiency gain of JRFit was up to 50% compared to restricted maximum likelihood for heavy-tailed and highly correlated data. Predictive performance evaluated using the mean absolute prediction error and mean prediction standard error from an out-of-sample cross-validation study showed JRFit to be optimal for providing predictions of baseflow on the basis of the phases of El Niño–Southern Oscillation and Atlantic Multidecadal Oscillation. Thus, it is recommended that JRFit be implemented in hydroclimatic studies to provide powerful inference when there is evidence of clustering in the data. ©2018. American Geophysical Union. All Rights Reserved.

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Water Resources Research

Evaluation of Nonparametric and Parametric Statistical Procedures for Modeling and Prediction of Cluster-Correlated Hydroclimatic Data

A recent alkali silica reaction (ASR)/delayed ettringite formation (DEF) expansion model was modified to account for the load-induced precracks within a structure. Factors such as the orientation of the exposure face, the reinforcement details, and the location of the strain measurements were also considered. The model was implemented for environmentally exposed large-scale reinforced concrete specimens. The model provided a satisfactory simulation of the expansion results, with most results within the extremities of the measured data. The model successfully simulated the expansion strains inside and outside the development length zone. The expansion induced by ASR/DEF deterioration mechanisms in large structural concrete members could be effectively modeled using the minimalist semiempirical formulation. © 2018 American Society of Civil Engineers.