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Full Paper Proc. of Int. Conf. on Advances in Design and Construction of Structures 2012

Effect of Use of Recycled Concrete Aggregates in Bituminous Concrete Surface Course Gurukanth S1, Donal Nixon D’souza2, Avinash Babu S3, Vivek A K4 and Dr.Srikanth M Naik5 1

UG Student, Department of Civil Engineering, MSRIT, Bangalore, India. Email: guru_kanth@hotmail.com 2 UG Student, Department of Civil Engineering, MSRIT, Bangalore, India. Email: donalnixon@gmail.com 3 UG Student, Department of Civil Engineering, MSRIT, Bangalore, India. Email: avinashbabu123@gmail.com 4 UG Student, Department of Civil Engineering, MSRIT, Bangalore, India. Email: vivekakannan15@gmail.com 5 Professor, Department of Civil Engineering, MSRIT, Bangalore, India. Email: srikanth_naik@yahoo.com I. INTRODUCTION

Abstract—India has a road network of over 4.32 million kilometres as of 2011, the third largest road network in the world. However, qualitatively Indian road network are a mix of modern highways, narrow paved roads & unpaved roads. As of 2008, 49% i.e. 2.1 million kilometres of Indian roads are paved. India plans to spend approximately 70 billion USD by 2013to modernize its road network. Several projects like Pradhan Mantri Grama Sadak Yojana (PMGSY) have been initiated by Government of India to upgrade rural roads to black top surface roads. Aggregates form a bulk of the material required for bituminous concrete pavements. Aggregate being a natural material is being fast consumed and is causing a shortage of resources required for rapid infrastructure development. Also on the other side with the new trends in construction industry there is a generation of solid waste in the form of demolished structures. Cement concrete being a non biodegradable element is a challenge to dispose.Generally demolished concrete ends up in landfills. However with new environmental regulations and limited space available, concrete disposal has been a major environmental challenge.Today, science and technology has a responsibility of innovating new trends which are both economical and ecofriendly. Old demolished concrete structures can be recycled to obtain recycled aggregate (RA). This can be used along with the natural aggregates effectively in various infrastructure need so that we attain a balance between demand and supply of construction material thereby reducing the impact on nature. The present investigation aims in the strength variation of bituminous concrete surface course in which recycled aggregates are used in partial or full replacement of natural aggregates. Marshall’s method is used to study the strength variations in bituminous concrete surface course with replacement of natural aggregates with recycled aggregates. It was found that replacement of natural aggregates by recycled aggregates upto 20% is possible in bituminous concrete surface course without significant impact on the strength characteristics. However there is an increase in the binder content for which there is a need to study the economic value of the replacement.

Aggregate form a major portion of the pavement structure and they form the prime material used in pavement construction. Aggregates have to bear stresses occurring due to the wheel loads on the pavement and on the surface course they have to resist wear due to abrasive action of traffic. These are used in pavement construction in cement concrete, bituminous concrete and other bituminous construction and also as granular base course underlying the superior pavement layers. Most of the road aggregates are prepared by crushing natural rock. Natural materials are of limited availability and its quantities are declining rapidly creating an acute shortage. It is estimated that 750 million cum of aggregate would be required for achieving the targets of the road sector [1]. Researchers are looking for alternative materials for highway construction which are economical and ecofriendly. Concrete recycling is becomining an increasingly popular way to utilize the aggregate left behind when structures and roadways are demolished [2]. In the past, this rubble was disposed off in landfills, but with more attention being paid to environmental concerns, with existing woes of solid waste management system and an aim towards sustainable development. Re-utilization or recycling seems to be an attractive alternative and an important strategy for management of such waste which could flourish as a good business, if done in a proper manner. For further utilization of recycled aggregates, a proper study needs to be done for its use in the construction and infrastructure projects. Recycling of concrete not only allows the reuse of the rubble, but also helps in conserving the natural resources, reducing the construction costs. Recycled aggregates (RA) can be obtained from crushed concrete rubble (from C & D wastes) comprising of crushed and uncrushed parent aggregate coated with mortar and small pieces of hardened mortar.

Keywords— Bituminous concrete surface course, Recycled aggregate, Marshall’s method.

© 2012 ACEE DOI: 02.ADCS.2012.1. 506

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