INTRODUCTION
1.1 BACKGROUND
Aggregates are very important constituent in construction work. They reduce shrinking, give body to concrete and effect economy. (Shetty, 2005). In road construction, aggregates are combined with asphalt binding medium to form a compound material. It can also be use with a stabilizer or by self for base and sub-base courses.
Aggregates are used in almost all construction works like:
1. Road bases and sub-bases
2. Asphalt concrete
3. Asphalt surface
4. Portland cement concrete
5. Rails and ballasts
6. Trench backfill
7. water filtration beds
8. Rip rap and gabion materials
Aggregates were earlier considered as a chemically inert material but now it has been found out that some of the aggregates are chemically active and also that some aggregate exhibit chemical bonds at the interface of aggregate and cement paste.
Aggregate can occur naturally or artificially. Naturally curing aggregates are particles resulting from the weathering of rocks. They can be gotten from rivers, say gravels and sand stone or crushed rock called chippings.
The mere fact that aggregate occupy 70-80 percent of the volume of concrete and 40 percent of asphalt concrete, has an impact on various characteristics and properties of concrete and asphalt.
To know more about concrete, it is important that one should know more about aggregate, which constitute the major volume.
In Nigeria, the basic sources of aggregate either for concrete work or road constructions are from those occurring naturally which are cheaper and readily available. The most widely used aggregate is crushed rock, which are blasted from natural depositions and crushed to different sizes depending on the purpose and use. The study of aggregates (their types, properties and test) is of great important to the Civil Engineering.
This study is to ascertain the different properties of aggregates used in construction works. This process of testing provides or establishes a common basis for comparison of aggregates from different sources and to interchange ideas between different locations.
In this project work, we will be looking at different properties of coarse aggregates from different sources.
Case study include:
– Abakaliki
– Lokpanta
– Otanmiri River
The locations are all in South-Eastern part of Nigeria.
1.2 SCOPE OF THE STUDY
This project work is limited to the investigation of the properties of coarse aggregate from different sources, including. Otanmiri River, Lokpanta quarry site and Abakaliki quarry site. All in South Eastern part of Nigeria.
1.3 SIGNIFICANCE OF THE STUDY
This project will be of great importance to construction firms that make use of aggregate.
Secondly, this work will be relevant and important to all students in the field of civil engineering who wish to expand their knowledge about coarse aggregates.
1.4 OBJECTIVE OF THE STUDY
1. To determine the properties of coarse aggregate. Sample collected from different locations. Abakaliki, Lokpanta and Otanmiri, all in south east part of Nigeria.
2. To compare the properties of these aggregates from different sources.
3. To determine the strength of aggregate from different source and compare.
1.5 LIMITATIONS OF THE STUDY
During the course of this study, some constraints and limitations were encountered; the first limitation is that of sourcing for the material needed to carry on with the project work.
The second limitation is that of time. The time allocated for this project is short considering the practical involved.
The last limitation of this work is the availability of standard testing equipment, this limitation is the major limitation in this project and it led to the delay of the work as we source for the equipments required for the practical.
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