How would you say strength of concrete depends on shape and size of aggregates?
Shape of Aggregate – Rounded, Angular, Flaky, Elongated
- Rounded – minimum voids, require minimum cement but poor interlocking and bonding.
- Angular – Higher voids, require more cement, but best interlocking and bonding.
- Flaky: Aggregates having its least dimension less than 0.6 times its mean dimension. It has poor bonding and has adverse effect on homogeneity of mix and its strength.
- Elongated: Aggregates having its larger dimension greater than 1.8 times its mean dimension. It has poor bonding and not considered suitable for medium to high strength concrete
Size of Aggregate – Fine, Medium and Coarse
The maximum size aggregate gives the lower surface area for the development of gel bonds which is responsible for the low strength concrete. Also, non-uniformity in concrete.
Large Aggregate – Lean Mix – High Strength
Smaller Aggregate – Rich Mix –High Strength