Why is it recommended to use rounded aggregate for making PCC mixes rather than angular ones?

Rounded particles create less particle-to-particle interlock than angular particles and thus provide better workability and easier compaction.

Why are rough angular stones preferred rather than a smooth rounded one?

Rough, angular particles pack tighter, have more surface area, and have greater interparticle friction than smooth, rounded particles, which reduces workability. Angular particles also require a bit more cement paste to coat them than rounded particles.

Which type of aggregates we should prefer for better workability?

Rounded aggregates have a lower surface area, but lack the angularity to develop sufficient bond strengths with the cement paste. Crushed aggregate with the proper proportions provides a better bond with the cement matrix and adequate workability.

Why is coarse aggregate important?

Coarse aggregates are defined as any material greater than 4.75 mm. Aggregates make up 60-80\% of the volume of concrete and 70-85\% of the mass of concrete. Aggregate is also very important for strength, thermal and elastic properties of concrete, dimensional stability and volume stability.

What is the importance of aggregates in making concrete?

Aggregate materials help to make concrete mixes more compact. They also decrease the consumption of cement and water and contribute to the mechanical strength of the concrete, making them an indispensable ingredient in the construction and maintenance of rigid structures.

How do Using rough textured or angular aggregates affect mix proportion?

How do Using rough textured or angular aggregates affect mix proportion? Rough-textured, angular, and elongated particles require more water to produce workable concrete than smooth, rounded compact aggregate. Consequently, the cement content must also be increased to maintain the water-cement ratio.

What is the importance of coarse aggregate texture?

The surface texture of aggregate can be either smooth or rough. A smooth surface can improve workability, yet a rougher surface generates a stronger bond between the paste and the aggregate creating a higher strength.

How do you choose aggregates?

Aggregates need to be hard, strong, chemically inert, and non-porous. Organic substances and dirt coating compromise the strength and durability of concrete. Coarse aggregates should not absorb moisture by more than 10\% of their weight after submersion in water for 24 hours.

How can you select good quality aggregate?

Quality Counts Good-quality aggregate must be clean, hard, strong, have durable particles, and be free of absorbed harmful chemicals, coatings of clay, or other contaminates that can affect hydration of cement or reduce the paste-aggregate bond.