Why do we use 40mm aggregate in PCC?

Why do we use 40mm aggregate in PCC?

Why 40mm size aggregate is preferred in PCC or mass concrete than 20mm :- for the same strength or workability, concrete with large size aggregate will require lesser quantity of cement than concrete with a smaller size aggregate.

What is the size of concrete?

Standard Cement Concrete Block, Size (Inches): 24 inches x 8 inch.

Which aggregate is used in PCC?

Coarse aggregate used in the PCC must be of hard broken stone of granite or similar stone, free from dust, dirt and other foreign matter. The stone ballast shall be 20 mm in size and smaller. All the coarse material should be retained in a 5mm square mesh and should be well graded so that the voids do not exceed 42\%.

What is the maximum size of aggregate used in concrete?

The maximum size aggregate used may be dependent upon some conditions. In general, 40mm size aggregate used for normal strengths and 20mm size is used for high strength concrete. The size range of various coarse aggregates given below: Fine gravel: 4mm – 8mm

What is the difference between coarse and mass concrete?

A larger size, 40mm, is more common in mass concrete. Larger aggregate diameters reduce the quantity of cement and water needed because of its lower Voids. When the aggregate is sieved through 4.75mm sieve, the aggregate retained is called coarse aggregate. Gravel, cobble and boulders come under this category.

What size of aggregate is used in RCC structure?

Generally the most appropriate size of aggregate used in RCC structure is 20mm. It gives more strength to the structure. When there is no restriction to the flow of concrete, 40 mm or larger aggregate is preferred. In thin sections, small cover or closely-spaced reinforcements, considerations should be given to use 10 mm aggregate.

What is coarse aggregate size?

When the aggregate is sieved through 4.75 mm size the aggregate is retained is known as coarse aggregate. Larger than 4.75mm size is coarse sand or aggregate, so coarse aggregate size arranging between 5mm to 256 mm or more.