Department of Chemistry

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1924

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Start date: 2010Subject: search.filters.subject.Civil Engineering

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Now showing 1 - 10 of 24
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    Recycled aggregate concrete: Particle Packing Method (PPM) of mix design approach
    (Elsiever, 2017-10) Barai, Sudhir Kumar
    A sustainable and eco-friendly approach is essential for the construction industry, as it is one of the major sectors responsible for the depletion of the natural resources and the generation of greenhouse gases. In this context, the recycled aggregate (RA) is an effective alternative to natural aggregate. But, the use of RA has not gained popularity yet, because of the inferior quality of RA and yielded recycled aggregate concrete (RAC) using RA. The proposed Particle Packing Method (PPM) of design mix is executed along with the established Two Stage Mixing Approach (TSMA) to produce RAC by completely replacing the natural coarse aggregate. The synergistic effect of PPM design mix and TSMA on fresh and hardened stage performance of RAC were studied. In this context, a comparative analysis showed encouraging results for the PPM design mix as compared to the IS: 10262 (2009) method of mix design approach.
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    Data mining applications in transportation engineering
    (Taylor & Francis, 2011-12-19) Barai, Sudhir Kumar
    Data mining is the extraction of implicit, previously unknown and potentially useful information from data. In recent time, data mining studies have been carried out in many engineering disciplines. In this paper the background of data mining and tools is introduced. Further applications of data mining to transportation engineering problems are reviewed. The application of data mining for typical example of ‘Vehicle Crash Study’ is demonstrated using commercially available data mining tool. The paper highlights the potential of data mining tool application in transportation engineering sector.
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    Determining the double-K fracture parameters for three-point bending notched concrete beams using weight function
    (Wiley, 2010-06-16) Barai, Sudhir Kumar
    Parameters of universal form of weight functions having four terms and five terms are derived for edge cracks in finite width of plate. The standard Tada Green's function is taken as the basis for the derivation. The shape of universal form of weight functions considered enables closed form expressions for cohesive toughness of three-point bending test geometry of notched concrete beams due to linear cohesive stress distribution in the fictitious fracture zone. This solution provides a viable method to determine the double-K fracture parameters: the initiation toughness, inline image and the unstable toughness inline image for mode I fracture of concrete beam. A comparison with existing analytical method shows that the weight function method for determination of the double-K fracture parameters yields results without any appreciable error. The use of weight function will not only simplify the calculation to obtain the double-K fracture parameters, inline image and inline image but also it will avoid the need of skilled numerical integration technique due to singularity problem at the integral boundary.
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    Influence of incorporation of nano-silica and recycled aggregates on compressive strength and microstructure of concrete
    (Elsiever, 2014-11-30) Barai, Sudhir Kumar
    The present investigation deals with the study of compressive strength and characteristics of the Interfacial Transition Zone (ITZ) of concrete containing recycled aggregates and nano-silica. For this purpose, compressive strength at 7, 28, 90 and 365 days are determined for fully natural and recycled aggregate concrete mixes made with or without nano-silica. In addition to above, Vickers microhardness test and backscattered-mode scanning electron microscopic analysis is carried to characterize ITZ of concrete mixes. The results of study depict that full replacement of natural coarse aggregates with recycled ones have significant effect on compressive strength and ITZ characteristics of concrete. However, compressive strength and microstructure of concrete mixes improves with the incorporation of nano-silica.
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    Concrete fracture models and applications
    (Springer, 2011) Barai, Sudhir Kumar
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    Influence of Nano-Silica on the properties of recycled aggregate concrete
    (Elsiever, 2014-03) Barai, Sudhir Kumar
    The present work addresses the effect of incorporation of colloidal Nano-Silica on the behavior of concrete containing 100% recycled coarse aggregate. In this study, concrete mixes containing both natural and recycled aggregate are produced by replacing a fraction of Portland cement 0.75%, 1.5% and 3% of colloidal Nano-Silica respectively. The results of experimental investigation depicts that compressive strength, tensile strength and Non-Destructive parameters are enhanced due to addition of NS. Moreover, the study reveals that the characteristics of recycled aggregate concrete resembles with that of natural aggregate concrete with the addition of little amount (3%) of Nano-Silica.
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    Behaviour of recycled aggregate concrete under drop weight impact load
    (Elsiever, 2011-01) Barai, Sudhir Kumar
    This paper presents the experimental results of recycled aggregate concrete (RAC) beams prepared with different amount of recycled coarse aggregate (RCA) subjected to low velocity impact. The recycled coarse aggregates are obtained from a demolished RCC culvert. Four concrete mixes with 0%, 25%, 50% and 100% RCA respectively are prepared. With each mix three beam specimens of size 1.15 × 0.1 × 0.15 m are prepared and tested under drop weight impact load. The behavior of the RAC beams are studied in terms of acceleration, strains and support reaction histories under impact load in addition to the physical and mechanical characteristics of RCA and RAC. It is observed that 25% RCA does not influence the strength of concrete. In addition, it is found that for a given impact energy (the energy imparted by the hammer per blow) the reactions and strains of RAC with 50% and 100% RCA are significantly lower and higher respectively than those of normal concrete and RAC with 25% RCA.
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    Influence of field recycled coarse aggregate on properties of concrete
    (Springer, 2010-05-06) Barai, Sudhir Kumar
    This paper investigates the influence of different amounts of recycled coarse aggregates obtained from a demolished RCC culvert 15 years old on the properties of recycled aggregate concrete (RAC). A new term called ‘‘coarse aggregate replacement ratio (CRR)’’ is introduced and is defined as the ratio of weight of recycled coarse aggregate to the total weight of coarse aggregate in a concrete mix. To analyze the behaviour of concrete in both the fresh and hardened state, a coarse aggregate replacement ratio of 0, 0.25, 0.50 and 1.0 are adopted in the concrete mixes. The properties namely compressive and indirect tensile strengths, modulus of elasticity, water absorption, volume of voids, density of hardened concrete and depth of chloride penetration are studied. From the experimental results it is observed that the concrete cured in air after 7 days of wet curing shows better strength than concrete cured completely under water for 28 days for all coarse aggregate replacement ratios.
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    The impact of construction of hill roads on the environment, assessed using the multi-criteria approach
    (Taylor & Francis, 2021-03-30) Singhal, Anupam; Singh, Ajit Pratap; Mittal, Ravi Kant
    The environmental impact assessment (EIA) in regard to road widening of a 26 km stretch in Reasi District of Jammu and Kashmir (Union Territory) has been studied. Impact on the environment included temperature, deforestation, rainfall, landslides, blasting, surface and groundwater, air and soil pollution, habitat change, historical and socio-environmental factors. The study indicates that buses are the highest emitters of Hartridge Smoke Unit (HSU) followed by light commercial vehicles, heavy commercial trucks and cars, and three-wheelers in that order. The study also established that the make and age of the vehicle had negligible impact on the observed values of HSU and the light absorption coefficient (k). With the help of multi-criteria tools, the EIA has been quantified for four alternatives of a road stretch using fourteen criteria. The results show that the impact of the construction of two-lane highways on the environment is high, but that it can also be mitigated effectively.
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    Urban Policymaking for a Developing City Using a Hybridized Technique Based on SWOT, AHP, and GIS
    (ASCE, 2021-06) Singhal, Anupam; Routroy, Srikanta
    The high rate of population growth in the 21st century is causing mass migration from rural to urban settlements. Rapid urbanization in developing countries generally follows unregulated growths, urban sprawls, and inefficiencies in city planning. With the trend of rapid growth in developing countries, it has been very difficult to maintain an environmentally sustainable and socially resilient policy framework. This study proposes an urban development policy framework for sustainable planning in developing cities by coupling geographic information system (GIS) geospatial zonal analysis with strength, weakness, opportunities, and threats (SWOT) and analytical hierarchy process (AHP) model. The hybridized approach incorporates critical issues such as disaster impact, slum settlements, infrastructure deficit, and noise pollution in urban planning. A case study of the city of Delhi was taken to demonstrate the applicability of the proposed framework in developing cities. The novelty of the study is that it proposes a highly flexible urban development plan based on the integrated GIS and SWOT-AHP methodology that is specific to the needs of developing economies and developing cities. The methodology also puts a strong emphasis on disaster prevention and response in the urban development plan. Results from the GIS–SWOT-AHP model can be used for region-based urban planning that prioritizes regions needing critical attention and directs the development of the city toward a sustainable future.