i-manager's Journal on Civil Engineering (JCE)


Volume 5 Issue 1 December - February 2015

Research Paper

Laboratory Investigation of Warm Mix Asphalt with the Inclusion of Recycled Aggregate

K. Naresh* , A. Ramesh**, M. Kumar***
* PG Student, Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Telangana, India.
** Associate Professor, Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Telangana, India.
*** Professor & Head, Department of Civil Engineering, University College of Engineering, Osmania University, Telangana, India.
Naresh.K., Ramesh.A., and Kumar.M. (2015). Laboratory Investigation of Warm Mix Asphalt with the Inclusion of Recycled Aggregate. i-manager’s Journal on Civil Engineering, 5(1), 1-8. https://doi.org/10.26634/jce.5.1.3136

Abstract

Pavement construction evolves with the use of large quantities of natural aggregates (NA). The bulk use of natural aggregates in pavement layers is a disturbing situation and is resulting in demolishing of natural resources. In flexible pavements, hot mix asphalt is used for construction of surface and binder course layers. The hot mix asphalt when prepared at mixing temperature, releases harmful gases and pollutes the environment. Several techniques have been developed to reduce the mixing and compaction temperatures of hot mix asphalt. One of the technologies is named as Warm Mix Asphalt (WMA). WMA mixes contribute cost savings in operation of bitumen plants through reduction of energy costs. Warm mixes also allow articulated vehicle of asphalt loads for longer distances, without any delay and significant loss in temperature. In this context, an attempt is made in the laboratory for appreciating the influence of recycle aggregates (RA) on characteristics of warm mix asphalt. Performance characteristics were evaluated through Satiability and Indirect Tensile Strength (IDT). Recycled aggregate was added proportionately at 10%, 15% and 20% of virgin warm mix asphalt. It was observed that stability values are higher for WMA of recycled aggregate as compared with traditional asphalt mix. 15%RA has exhibited improved characteristics than when compared with the other two percentages of recycled aggregates.

Research Paper

Temporal Development of Local Scour Around Bridge Pier

Shiv Kumar Yadav* , Shri Ram**
* Post Graduate Student, Civil Engineering Department, Madan Mohan Malaviya University of Technology, Gorakhpur (U.P.), India.
** Associate Professor, Civil Engineering Department, Madan Mohan Malaviya University of Technology, Gorakhpur (U.P.), India.
Yadav,S,K., and ShriRam (2015). Temporal Development of Local Scour Around Bridge Pier. i-manager’s Journal on Civil Engineering, 5(1), 9-15. https://doi.org/10.26634/jce.5.1.3137

Abstract

When an alluvial stream is partially/fully obstructed by a bridge pier, scour takes place in the vicinity of the pier. Estimation of this scour depth is a major concern of bridge engineers. The underestimation of scour depth leads to unsafe design, while an overestimation leads to uneconomical design. Therefore, estimation of anticipated maximum scour depth for given design discharge is essential. Scour at bridge piers is mainly affected by pier, flow and sediment characteristics. On the basis of field investigations, many investigators have suggested criteria for assessing maximum scour depth around bridge pier in alluvial bed. These studies are mainly regarding scour around bridge piers at normal flow conditions. Adequate information in connection with scour at bridge pier at different depth of flow, piers size and sediment size is not available. From the observation, we found that scour depth goes on increasing with increase in pier diameter.Out of these, the effects of pier size and shape, and of the approach flow angle on scour depth are fairly well understood. The effects of flow depth and sediment non-uniformity on scour depth have been also studied in detail. In this paper, a method has been presented to estimate the time variation of scour depth with uniform and nonuniform sediments. The procedure has been developed for computing the time variation of scour depth which is based on the dimensional analysis, and considering the horse-shoe vortex system to be the main scouring agent.

Research Paper

Formulation of Transient Uplift Pressure in Cracks of Concrete Gravity Dams

K.K.Pandey* , N.Kumar**, V.Kumar***
* Associate Professor, Civil Engineering Department, IIT (BHU) Varanasi, Uttar Pradesh, India.
** Engineer, Tata Consulting Engineers Ltd., Ranchi, Jharkhand, India.
*** Professor, Civil Engineering Department, IIT (BHU) Varanasi, Uttar Pradesh, India
Pandey.K.K., Kumar.N., and Kumar.V. (2015). Formulation of Transient Uplift Pressure in Cracks of Concrete Gravity Dams. i-manager’s Journal on Civil Engineering, 5(1), 16-25. https://doi.org/10.26634/jce.5.1.3138

Abstract

Safety guidelines recommend the presence or absence of an assumed static uplift pressure in cracks at damfoundation interface during seismic activity. In recent past, some research work has been done to develop a mathematical model for transient uplift pressure in smooth walled cracks under laminar flow conditions. In this paper, a mathematical model for transient uplift pressures in real cracks under both laminar and turbulent flow regimes are developed. One dimensional continuity and momentum equations have been coupled to derive the governing integral equations of pressure as a function of crack wall motion history and flow regimes (i.e. laminar/turbulent). These equations are supplemented with required number of boundary conditions based on the understanding of hydraulic phenomenon described in the literatures. Model is used to solve the transient uplift pressure in wedge shaped crack of constant length and is validated using the experimental data from literature. A difference (less than 5%)between computed and measured value of uplift pressure occurs at beginning and end of the opening-closing cycle of the crack in comparison to other points of time. These differences may be attributed to violation of some assumptions used in the problem formulation (e.g. vapour pressure at point of saturation may not be zero and two-phase flow may occur in unsaturated portion of the crack) or the possibility of cavitation in unsaturated portion of the crack. However, overall computed pressure variation obtained using present formulations are in good agreement with experimental data from the literature.

Research Paper

Utilization of Mine-Ore Tailings for the Production of Stabilized and Pressurized Building Blocks

Prahallada M.C.* , Shanmuka K.N**
* Professor, Department of Civil Engineering, Christ University, Faculty of Engineering, Bangalore, Karnataka, India.
** Assistant Professor, Department of Civil Engineering, Smt. Kamala & Sri Venkappa M. Agadi College of Engineering and Technology, Karnataka, India.
Prahallada.M.C., and Shanmuka.K.N. (2015). Utilization of Mine-Ore Tailings for the Production of Stabilized and Pressurized Building Blocks. i-manager’s Journal on Civil Engineering, 5(1), 26-32. https://doi.org/10.26634/jce.5.1.3139

Abstract

Mine (Iron ore, Copper and Manganese ore) tailings are industrial waste material obtained in the mines, after the extraction of concentration from the ore. Some percentage trace of ore properties will be left in the ore waste after the extraction process is completed, known as tailings. These ore tailings which are produced in large quantity in the ore mines, which is unfit for farming and makes the land barren. Disposing of this tailing from the mines premises is a big head ache for the concerned authorities. The use of any industrial waste in construction acts as an environmental friendly project. These industrial wastes always cause pollution and their disposal is a problem for the concerned authorities, because either they occupy lot of space for their storage or they pollute the media in which they are discharged. In this experimental work, an attempt has been made to study the suitability of ore tailings in the preparation of building blocks by stabilizing it through cement. Different percentages of cement are being used for the stabilization. Dry compressive strength, wet compressive strength, moisture absorption and erosion resistance were found out on the prepared specimens. The results show that the stabilized building blocks of mine ore tailings with 7% addition of cement and 7% cement with extra percentage of sand show the maximum compressive strength with advantage in other properties.

Research Paper

Optimization of Pipeline Flow of Fine Particles Slurry Using Genetic Algorithms

Sanjay Kumar Srivastava* , Rajesh Kumar**, Prabhat Kumar Singh Dikshit***
*Ph. D. Scholar, Department of Civil Engineering, IIT (BHU), Varanasi, India.
** Associate Professor, Department of Civil Engineering, IIT (BHU), Varanasi, India.
*** Professor, Department of Civil Engineering, IIT (BHU), Varanasi, India.
Srivastava,S,K., Kumar,R., and Dikshit,P,K,S. (2015). Optimization of Pipeline Flow of Fine Particles Slurry Using Genetic Algorithms. i-manager’s Journal on Civil Engineering, 5(1), 33-37. https://doi.org/10.26634/jce.5.1.3140

Abstract

Liquid and solid are two phase flows, stated to as slurries. Slurry particle less than 40 μm (fine particles) in turbulent flow behave in a homogeneous manner. They are referred to as non-setting slurry. The particles’ concentrations are almost similar across the cross section of pipe. The characteristics of slurry such as unsteady flow rate, complicated ingredients, high concentration and viscosity of liquid carrier are subjected to pipeline blockage and high energy consumption. The pressure drop is a key parameter in the design of slurry pipelines, as it delivers evidence on the power required to continue a flow rate above the critical deposition velocity. As the pressure drop in pipeline is directly proportional to the energy consumption, to minimize the pumping cost of slurry, the pressure drop must be minimum. This paper presents an overview on the head losses in pipeline for slurry flows. The minimization of the head loss is considered as the objective function. Genetic algorithm is used as the optimization technique and code is developed in MATLAB.