Description

ABSTRACT

Solid waste management has become one of the global environmental issue, as there is increase in industrial by- products and waste materials due to lack of land filling space and it sever increasing cost, utilization of waste material and by- products has become an attractive alternative to disposal. WFS is one of such industrial by- product and can be utilize in reducing the cost of construction materials and also help in reducing disposal problem. Mar shall method of mix design was used and bitumen content of 4.5%, 5.0%, 5.5%, 6.0% and 6.5% was adopted, optimum bitumen content of the control was found to be 5.5% which was then used to design varying percentages of WFS in the following other 5%, 10%, 15%, 20%, 25%,30%. The result obtained shows that the WFS mixes exhibit satisfactory trend result with an average bitumen content of 5.5% the optimum stability was attained at 30% replacement of WFS with a value of 6.32KN and optimum f low value of 3.53mm at 15% replacement of WFS. From the Mar shall stability- f low test analysis, the sample prepared with 30% WFS as fine aggregate with OBC of 5.5% satisfied the provision of the standard specification requirement by NGSRB.

 

1.0 INTRODUCTION

1.1 Background of the study

Highway pavement is defined as the durable surface material laid down on an area intended to sustain vehicular or foot traffic. It is also defined by the American Road engineers as the various layers of materials of which the road is constructed above the level of formation of the subgrade (ORN 19, 2002).

The top most portion of the pavement is made of asphalt concrete which is a mixture of bitumen, coarse aggregate, fine aggregate and miner al  filler  in different proportion, depending on the type of asphalt mixture (Garber and Hoel, 2009). Asphaltic pavement is incomplete or becomes unstable without fine aggregate. The addition of Fine aggregate to hot mix asphalt (HMA) is to improve the density and strength of the mixture. In addition, contributes to the interlocking proper ties of the particles while at the same time reducing the voids in the coarse aggregate. It uses in flexible pavement is to resist rutting, fatigue, low temperature cracking and other distresses (Raji, 2016).

All road pavements require the efficient use of locally available materials if economically constructed roads are to be built. This requires the design engineer to have a thorough understanding and knowledge of the properties of the materials that affect pavement stability and durability (O’Flaherty, 2002).

Metal foundries utilize high quality sands in production of metal castings. The sand is mixed with variety of additives and binders according to type of metal casting. It is recycled and reused multiple times in the process until it loses its characteristics and thus discarded Rashid et al, 2014. foundry sand discarded by foundries is called waste foundry sand (WFS). Accor ding to researcher Jalali (2009), waste foundry is a mixture of sand, residues f r om metal casting process and variety of binder s. It is the by- product of ferrous and non- ferrous metal casting industry, the physical and chemical properties of waste foundry sand (WFS) depend upon: type of metal being poured, casting process, type of binder system, type of furnaces and type of finishing process like grinding, blast cleaning and coating (Singh et al, 2012). Depending on type of binder systems used in metal casting process, waste foundry  sands are classified as;  clay  bonded sand (Green sand) and chemically bonded sands. Green sand is black in colour due to high carbon content. Being a combination of sand, clay and water , waste green sands are effective in geotechnical applications like base courses, structural f ills, embankments etc (Rashid et al, 2014). Chemically bonded sand is utilized in mould making as well as in core making where high strengths are essential to bear the high temperature of molten metal. Colour of chemically bonded sand is lighter than clay bonded sands. Their texture is coarser than clay bonded sands. Chemically bonded sands lack the hydraulic characteristics of green sand and are effective in agricultural and construction use. (AFS- FIRST, 2011)

The phenomenon of reusing WFS in applications other than land fills is quite well established in places like Europe, England and North America, where WFS is utilized in manufacturing of cement, concrete, asphalt, bricks and controlled low strength material (CLSM).

In this study, the green sand (clay bounded) would be used as replacement f or fine aggregate to determine it effect on proper ties of asphalt concrete mixture.

1.2          Statement of Problem

The disposal of industrial by product such as, crush glasses, coal bottom ash, ir on slag, waste foundry sand etc, has become one of the major concern across the globe in most cases they are stock filed and these particles occupies a significant portion of land and causes many serious environmental problems (Suji et al, 2016) Researchers have been investigating the recycling, reusing and utilization of these industrial by product to be used in concrete, mortar and asphalt production. The effective utilization of this waste will solve the environmental problems attributed to the dumping waste foundry sand as landfill and also reduce the cost of asphalt production.

1.3  Aim and Objectives of Study

1.3.1 Aim

This study is aimed at evaluating the effect of waste foundry sand as fine aggregate on properties of asphalt concrete mixture.

1.3.2       Objectives of study

The objectives of this study are:

1. To determine the physical properties of fine and coarse
2. To find out the physical and chemical properties of waste foundry

3. To deter mine  the  chemical  composition  of   waste  foundry   sand  using  x- ray fluorescence (XRF)
4. To prepare asphalt concrete briquette with 0%, 5% 10%, 15%, 20%, 25%, 30% replacement of fine aggregate with waste foundry sand using Mar shall Mix design
5. To evaluate the strength and durability analysis of the asphalt concrete using Mar shall Stability