Which shape of aggregate is better suited for concrete making?

Which shape of aggregate is better suited for concrete making?

The shape and texture of aggregate affects the properties of fresh concrete more than hardened concrete. Concrete is more workable when smooth and rounded aggregate is used instead of rough angular or elongated aggregate.

Which aggregate is best for construction?

The typical coarse aggregate size ranges from 4.75 mm to 18 mm. Gravel or broken stone aggregates with rough and non-glassy texture are the best aggregates because they create a good bond with the cement paste. Aggregates need to be hard, strong, chemically inert, and non-porous.

Why flaky and elongated aggregates are not preferred in construction?

Due to high surface area to volume ratio, the flaky and elongated particles lower the workability of concrete mixes. Flaky and elongated particles are considered undesirable for base coarse construction as they may cause weakness with possibilities of braking down under heavy loads.

Why are flaky aggregates not preferred?

Flaky particles tend to orient in one plane and cause laminations which adversely affect the durability of the concrete. Flaky aggregate was shown to have lower compatibility and higher breakage . Highly flaky aggregates have more voids and reduce the workability.

What is effect of flaky and elongated aggregates?

The results reveal that the effect of elongated aggregates is more than flaky aggregates, on the characteristic compressive strength of concrete. Concrete with 1:1 ratio of flaky to elongated aggregates possesses minimum weight.

What are flaky and elongated aggregates?

When the aggregate length is larger than its width and width is larger than its thickness then it is said to be flaky and elongated aggregates.

Which type of aggregate is preferred for pavement construction?

Flaky and Elongated aggregates have lower strength. So, generally round and angular are preferred. Adhesion simply means a binding property with other materials. So, aggregate should have proper or good binding properties with bitumen/asphalt/tar.

How can we differentiate between flaky and elongated aggregates?

Why the presence of flaky and elongated particles are considered undesirable in the construction of base and surfacing layers of a road pavement?

For base course and construction of bituminous and cement concrete types, the presence of flaky and elongated particles are considered undesirable as these cause inherent weakness with possibilities of breaking down under heavy loads.

Why does flaky and elongated Aggregatesregarded as unsuitable materials for use in asphalt mix?

In general, aggregate characteristics are critical to the performance of asphalt mixture. Therefore, flaky aggregate is normally avoided simply because it has significant contribution towards the gradation and reduces the interlocking characteristics of aggregates within asphalt mixture.

What are flaky aggregates?

Flaky aggregate is defined as an aggregate particle with a least dimension (thickness) less than 0.6 of the mean of the smallest sieve size through which the particle passes and the largest sieve size on which the particle is retained.

Why is angular aggregate suitable for high strength concrete?

For constant water cement ratio and workability the requirement of cement increase. The interlocking between the aggregate particles is the best and hence the development of bond is very good. This is why angular aggregate is very suitable for high strength concrete and for pavements subjected to tension.

What is the difference between flaky aggregates and elongated aggregates?

If the aggregates breaks under a lod before failure of cement sand matrix. the concrete produced with that aggregates will not achieve the desired strength. Flaky means have less thickness, elongated means having more length.

What are the classification of aggregates based on shape?

Classification of Aggregates Based on Shape 1 Rounded Aggregate. The rounded aggregates are completely shaped by attrition and available in the form of seashore gravel. 2 Irregular Aggregates. 3 Angular Aggregates. 4 Flaky Aggregates. 5 Elongated Aggregates. 6 Flaky and Elongated Aggregates.

What are the disadvantages of rounded aggregate?

The only disadvantages is that the interlocking between its particles is less and hence the development of bond is poor. This is why rounded aggregate is not suitable for high strength concrete and for pavements subjected to tension.