Effect of Foundry Sand and Steel Fibres on the Strength Characteristics of Pavement Quality Concrete

Abstract

The world’s second largest road network of almost 3.5 million Km consisting of both paved and unpaved surfaces is in India. Roads in India are presently constructed not with the right choice of material. Bitumen and concrete are the two major types of materials used in road construction in the country. Construction of concrete roads in the country is of very small share. There is growing interest in the construction of concrete pavements, due to its high strength, durability, better serviceability and overall economy in the long run. The thrust nowadays is to produce thinner and green pavement sections of better quality, which can carry the heavy loads. The high strength steel fibre reinforced concrete is a concrete having compressive strength greater than 40MPa, made of hydraulic cements and containing fine and coarse aggregates; and discontinuous, unconnected, randomly distributed steel fibres. The present study aims at, developing pavement quality concrete mixtures incorporating waste foundry sand as partial replacement of fine aggregate as well as steel fibres. The aim is to design of slab thickness of PQC pavement using the achieved flexure strength of the concrete mixtures for different percentage of steel fibres and replacement of fine aggregates with waste foundry sand are reported. It is found out the maximum increase in flexure strength and compressive strength is for 30% waste foundry sand and 1% Steel fibre. Due to this increase in the flexural strength it is possible to achieve a savings in cost of Pavement Quality Concrete construction. In this study it has been observed that with 30% replacement of fine aggregates with foundry sand and addition of 1% steel fibres, the maximum saving of 21.14% in cost per kilometre has been achieved for the 8.5m wide PQC carriageway by calculating the thickness required for the PQC slab as per IRC:58-2002.