Question

- Which component occupies the most weight and volume in concrete?

Cement

Sand (Fine Aggregate)

Crushed Stones (Course Aggregate)

Water

- Low Heat Portland Cement is preferred in mass concrete work such as dams because...

Rapid hardening of concrete is required for such structures

They have higher ultimate strength

Development of cracks is minimized

- In the making of concrete,

Water reacts with stones to give the strength to concrete.

Stones and sand react with each other to give the strength to concrete.

Cement reacts with sand to give strength to concrete.

Cement reacts with stone to give strength to concrete.

Cement reacts with water to bind all the materials together that give strength to concrete.

Answer 1

• Obviously the crushed stones (coarse aggregates) occupies the maximum volume as well as weight of the concrete. For example if we take M-20 grade concrete, in this the mix is prepared by 1: 1.5 : 3, so if cement is 1 cubic meter, then sand will be 1.5 cubic meter and coarse aggregates will be 3 cubic meters. And we also know that density of coarse aggregates is maximum of cement, sand and water.
• Low heat Portland cement is preferred in Mass concrete work such as dams because due to minimized C3A low heat Portland cement has lesser heat of hyadration, so in Mass structures lesser cracks will develop.
• So for higher ultimate strength and lesser crack development low heat Portland cement should be used.
• Rapid hardening of concrete is suitable for repair of roads, Bridges where load is applied in a shorter duration.
• And lastly cement reacts with water to bind all the materials that give strength to concrete.

This solution will be helpful to you to making concept more clear.