What is the effect of size of aggregate on concrete?

What is the effect of size of aggregate on concrete?

A. As the nominal maximum size of the aggregate is increased, the amount of water needed for the same workability is reduced. At the same cementitious material content, strength is therefore greater because the w/cm is lower.

How does size of aggregate affect the workability?

Size of Aggregates On the other hand, bigger particles have less surface area, demand less water for wetting surface and require less amount of paste for lubricating. So bigger particles give higher workability for fixed water content.

Why is aggregate size important in concrete?

Aggregate is also very important for strength, thermal and elastic properties of concrete, dimensional stability and volume stability. Cement is more likely to be affected by shrinkage. Including aggregate in the mix can control the shrinkage level and prevent cracking.

What is the relationship between the aggregate particle size and concrete properties?

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.

What is the maximum size of aggregate used for concrete?

Generally the 9.5-37.5 mm diameter range aggregate are used in RCC concrete work. But Maximum size of aggregate generally on site used are 40 mm. For ease of compaction and workability sometimes on site 10-15 mm aggregate are used.

What is the maximum aggregate size?

Aggregate Size The smallest sieve opening through which the entire amount of aggregate is permitted to pass. coarse aggregate MUST pass the 1.5” sieve but 95 – 100% MAY pass the 1” sieve, therefore # 57 aggregate is considered to have a Maximum size of 1.5” and an Nominal Maximum size of 1”.

What are the factors that affect the workability of fresh concrete?

8 Factors that Affect the Workability of Fresh Concrete

• Water Content of the Concrete Mix:
• The Size of Aggregates:
• The shape of Aggregates:
• Surface Texture of Aggregates:
• The Porosity of Aggregates:
• Grading of Aggregates:
• Uses of Concrete Admixtures:
• Ambient Temperature:

What size aggregate should I use for concrete?

Typically the most common size of aggregate used in construction is 20mm. A larger size, 40mm, is more common in mass concrete. Larger aggregate diameters reduce the quantity of cement and water needed.

How does aggregate size affect water demand and cement content?

Their results confirm that increasing the maximum aggregate size reduces the total surface area of the aggregate, thus reducing the mixing water requirements; however, even with the reduction in water, a larger size aggregate still produces lower compressive strengths in concrete compared to concretes containing …

What is the maximum size of aggregate?

What are the different sizes of aggregate?

Coarse Aggregate

How does maximum size of aggregate affect concrete strength?

As the nominal maximum size of the aggregate is increased, the amount of water needed for the same workability is reduced. At the same cementitious material content, strength is therefore greater because the w/cm is lower.

What are the factors that affect workability of concrete?

Angular aggregates increases flakiness or elongation thus reduces workability. Round smooth aggregates require less water and less lubrication and greater workability in a given w/c ratio.

How does grading affect the workability of aggregate?

If grading of aggregate is varied, it also changes cement paste content (cost economy), workability of the mix, density and porosity. It is an important factor and has a maximum influence on workability. Well graded aggregates result in the least amount of voids in a given volume.

Which is better for workability cement paste or aggregate?

Lower aggregate /cement ratio implies more paste is offered to make the mix cohesive and gives greater workability. For aggregates of larger size, the surface area is less therefore less amount of water and cement paste is required to cover the surface area.