Aggregates are essential components of concrete. They act as inert material in concrete. Fine and coarse aggregate are two main types of aggregate for concrete. As the name indicates, they are basically classified depending on the sizes of aggregate particles. What is an Aggregate? Aggregates are the important constituents of the concrete which give body to the concrete and also reduce shrinkage. Aggregates occupy 70 to 80 % of the total volume of concrete. So, we can say that one should know definitely about the aggregates in-depth to study more about concrete. What is Fine Aggregate?? When the aggregate is sieved through a 4.75 mm sieve, the aggregate passed through it called as fine aggregate. Natural sand is generally used as fine aggregate, silt and clay have also come under this category. What is Coarse Aggregate?? When the aggregate is sieved through a 4.75 mm sieve, the aggregate retained is called coarse aggregate. Gravel, cobble and boulders come under this category. The maximum size aggregate used may be dependent upon some conditions. In general, 40 mm size aggregate used for normal strengths and 20mm size is used for high strength concrete. Difference Between Fine and Coarse Aggregate Fine and coarse aggregate have some major differences. Sources of main differences between deep and shallow footings are definition, size of particles, materials, sources, surface area, function in concrete, uses, etc. In the following table the main differences between Fine and coarse aggregate are given: From Dibyandu Pal— A Civil Engineer