Faculty Publications

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Author: search.filters.author.Ravi Shankar, A.U.Subject: search.filters.subject.Developing countries

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    Utilization of lateritic soil stabilized with alkali solution and ground granulated blast furnace slag as a base course in flexible pavement construction
    (Springer, 2020) Amulya, A.; Ravi Shankar, A.U.; Singh, A.; Pammar, K.H.
    The natural aggregates are depleting in developing countries due to the excessive usage in road and building construction. In the present study, the engineering properties of abundantly available lateritic soil stabilized with Ground Granulated Blast Furnace Slag (GGBS) and alkali solutions like Sodium hydroxide and Sodium silicate was evaluated. The suitability of stabilized soil as a base course in flexible pavements was investigated. The lateritic soil was treated with 15, 20, 25 and 30% of GGBS and alkali solutions consisting of 5% of Sodium oxide with Silica Modulus (Ms) of 0.5, 1.0 and 1.5 at a constant water binder ratio of 0.25. The improved unconfined compressive strength, flexural strength, and fatigue life were observed from the soil treated with 30% of GGBS and alkali solution having Ms 1.0 air-cured for 28 days at ambient temperature. The improvement is due to the formation of Calcium Silicate Hydrates and Calcium Alumino Silicate Hydrates from an exothermic reaction between Calcium ions and the dissolved silicates and aluminates present in GGBS and alkali solutions. The samples treated with 25, 30% of GGBS and alkali solution having 1.0 Ms cured for 28 days found to be durable in Wetting-Drying and Freezing-Thawing tests. The compact and densified crystal orientation of the treated soil samples was observed from the microstructure images obtained from the Scanning Electron Microscope technique. The design of low and high volume roads was suggested with stabilized soil and strains developed at different locations on the proposed pavement were analyzed using pavement analysis software. © 2020, Chinese Society of Pavement Engineering. Production and hosting by Springer Nature.
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    Effect of curbside bus stops on passenger car units and capacity in disordered traffic using simulation model
    (Taylor and Francis Ltd., 2022) Raj, P.; Asaithambi, G.; Ravi Shankar, A.U.
    Representation of traffic in terms of Passenger Car Unit (PCU) is imperative to estimate capacity in disordered traffic. Many studies have been conducted on investigation of impacts of traffic and geometric conditions on traffic characteristics and PCUs. However, the sensitivity of PCUs due to roadside frictions are not adequately studied. To address this gap, this study aims to estimate PCU values for vehicles under the influence of curbside bus stop, which is the most common roadside friction in developing countries. Lack of space for providing exclusive bus bays and higher demand for public transport buses in urban roads justify the need for this study. Methodology of this study involves development and validation of a microscopic simulation model to quantify the impact of curbside bus stop on PCU as well as capacity. The results indicate the significant differences in PCU values due to the presence of curbside bus stop with varying traffic volume and composition. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
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    Human Capital Approach for road accident costing in an Indian City
    (Institute for Transport Studies in the European Economic Integration, 2023) Sumayya Naznin, P.H.; Gidugu, S.; Cyril, A.; Ravi Shankar, A.U.
    The monetization of road crashes helps improve road safety awareness. This study focuses on the cost of Road Traffic Accidents (RTAs) in Ernakulam, a South Indian city, based on the Human Capital (HC) methodology, as it is most effective to estimate the cost of RTAs in developing nations. The loss is calculated from various data sources, including in-depth accident databases (police), questionnaire surveys, private hospital records, and vehicle garage bills considering the collision types. Most of the total costs are attributed to lost productivity, followed by medical expenses, vehicle damage, and human costs. Administrative costs comprise the smallest portion (0.73%) of the overall accident costs. The total cost estimation of RTAs in Ernakulam city for the years 2018 to 2021 is in the range of INR 66,96,04,438 to INR 103,05,12,440, which represents 0.44% to 0.7% of the city’s Gross Domestic Product (GDP), which is a non-repairable loss to the nation. © 2023 Institute for Transport Studies in the European Economic Integration. All rights reserved.