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INTRODUCTION
1.1 GENERAL
It is generally known that, the fundamental requirement for making concrete structures is to produce good quality concrete. Good quality concrete is produced by carefully mixing cement, water, fine & coarse aggregate and combining admixtures as needed to obtain the optimum product in quality & economy for any use. It is a known fact that concrete making aggregates constitute the lion share of the total volume of concrete. Due to the forecast shortfall in the supply of natural sands and the increased activity in the construction sector, it is apparent that looking for viable alternatives to the natural sand is a must. Time will come, when manufactured sand may play a significant role as an ingredient in concrete production.
1.2 MANUFACTURED SAND
Now a day’s sand is becoming a very scarce material, in this situation research began for inexpensive and easily available alternative material to natural sand. Some alternatives materials have already been used as a part of natural sand e.g. fly-ash, slag limestone and siliceous stone powder are used in concrete mixtures as a partial replacement of natural sand. However, scarcity in required quality is the major limitation in some of the above materials. Hence sustainable infrastructural growth demands the alternative material that should satisfy technical requisites of fine aggregate as well as it should be available abundantly. Manufactured sand is one such alternative.
Manufactured sand is defined as a purpose-made crushed fine aggregate produced from a suitable source material. Production generally involves crushing, screening and possibly washing. Manufactured sand has been produced by variety of crushing equipment including cone crushers, impact crushers, roll crushers, road rollersetc., The raw material for M sand production is the parent mass of rock. It is based on the parent rock that the chemical, mineral properties, texture, composition of sand would change.
1.3 ECO SAND
Now a day’s sand is becoming a very scarce material, in this situation research began for inexpensive and easily available alternative material to natural sand. Some alternatives materials have already been used as a part of natural sand e.g. fly-ash, slag limestone and siliceous stone powder are used in concrete mixtures as a partial replacement of natural sand. However, scarcity in required quality is the major limitation in some of the above materials. Hence sustainable infrastructural growth demands the alternative material that should satisfy technical requisites of fine aggregate as well as it should be available abundantly. Eco sand is one such alternative.
Eco Sand are very fine particles, a bi product from cement manufacture which can be used to increases efficiency in concrete. Its micro filling effect reduces pores in concretes and provides better moisture resistivity and thus durability. It has more consistent grading than many extracted aggregates. Effective use of eco sand waste material and thus cost effective and performs as well as naturally occurring sand. The use of eco sand rather than extracted or dredged natural sand will help designers and contractors address issues of sustainability. The present study is checking the compressive strength of concrete cube is using eco sand.
1.4 HISTORICAL BACKGROUND
Cement Concrete & Aggregates Australia (CCAA) developed a research programme in 2004 that examined the use of manufactured sand in Portland cement concrete. The research was conducted in two stages. Between 2004 and 2006 the physical properties of 21 manufactured sands that are commercially available in Australia were examined. Between 2006 and 2008 a second stage examined eight of the original twenty one samples selected to cover the range of physical properties identified in the first stage of the research project.
The attempts to produce crushed or manufactured sand in India could be traced to early 50's primarily in major dam works. The Indian Government has also taken steps to avoid the over exploitation of River sand, which ultimately lead to the usage of Manufactured Sand. The progress in the building material research and identification of role of particle shape and gradation of fine aggregates triggered the use of manufactured sand in the production of concrete. The complexity of construction and use of high strength concrete in large number of buildings is the prime mover along with the scarcity of river sand in many cities. In Tamil Nadu M-Sand is produced in large quantities in Karur, Tirupur, Coimbatore and Salem.
1.5 DEVELOPMENT IN PRODUCTION AND USAGE
The development of a technology (production and use) for manufactured aggregates has been driven by need. Thus we see that R&D on this topic internationally varies very much in dependence of the resources available. Japan is an example of a country that early started developing and applying new technologies, since their natural sand resources got totally depleted many years ago. On the opposite side, North American – especially Canadian – resource conditions have been (and still are) of an order that do not call for alternatives to glaciofluvial sand/gravel as aggregate.More than many European countries, Norway has been abundantly supplied with natural aggregates for construction purpose. Traditionally most concrete aggregates have been produced on the basis of glaciofluvial sand/gravel deposits, which offer rich but unevenly distributed resources throughout a country characterized by large transport distances.
During the last decades, however, crushed materials from hard rock quarries have won an increasing market share towards ready mixed concrete, besides also being the main product for asphalt pavements and road construction.
1.6 EFFECT OF M-SAND IN CONCRETE
Researchers concluded that, compared to concrete made from natural sand, high fines concrete generally had higher flexural strength, improved abrasion resistance, and higher unit weight and lower permeability due to filling the pores with micro fines. There is no appreciable difference in dry shrinkage in concrete made with Manufactured sand as compared to River Sand.
Manufactured sand is more angular and has rougher surface texture than naturally weathered sand particles. Aggregate that is more angular will have more water demands compared to river sand. Increase in water demand has to be compensated by the increasing cement content to maintain the same water cement ratio. Their particle size distribution helps in higher packing density which enhances the durability of the concrete.
Concrete mix proportions chosen should be such that the concrete is of adequate workability for the placing condition of the concrete and can properly be compacted with the means available. In hardened state concrete shall have required strength, durability and surface finish.
1.7 OBJECTIVES OF THE STUDY
The general objective of this project work is
To study the influence of manufactured sand on the compressive strength development of concrete and compare the result with that of concrete produced using selective river sand.
The specific objectives of this project are, therefore,
• To provide background information on manufactured sand, Eco Sand and its mix design process.
• To assess existing concrete produced using manufactured sand, Eco sand and compare with that of the conventional concrete.
• To conduct a cost comparison of concrete produced with and without manufactured sand & Eco Sand in different proportions.
• To draw a conclusion based on the research findings.