The workability of rounded aggregates for given water content is a go...
For a given water content round and cubical shape aggregates are more workable than rough, angular, or flaky aggregates because the former type of aggregates requires less cement paste for lubrication as these less surface area and lesser voids.
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The workability of rounded aggregates for given water content is a go...
Explanation:
Rounded aggregates require less cement paste for a given lubrication
When it comes to the workability of concrete, the shape and size of aggregates play a significant role. Rounded aggregates, as opposed to angular aggregates, have a smoother surface and are more spherical in shape. This characteristic of rounded aggregates affects the amount of cement paste required for a given water content and lubrication, making them a better choice for workability.
Reduced cement paste requirement:
1. Rounded aggregates have a smaller surface area compared to angular aggregates. This reduced surface area means that there is less need for cement paste to coat the aggregates, resulting in lower cement paste requirements.
2. The smooth and rounded shape of the aggregates allows for a better distribution of the cement paste, reducing the need for excess paste to fill in gaps or voids between the aggregates.
Improved lubrication:
1. The rounded shape of aggregates allows for easier movement and flow of the concrete mix, resulting in improved lubrication. This means that less additional water or cement paste is required to achieve the desired workability.
2. The smooth surface of rounded aggregates reduces the friction between the aggregates, allowing them to slide past each other more easily. This further enhances the lubricating properties of the concrete mix.
Benefit of reduced cement paste:
1. The use of less cement paste not only reduces the cost of materials but also decreases the shrinkage and cracking potential of the concrete.
2. Excessive cement paste can lead to a higher water-cement ratio, which can result in lower strength and durability of the concrete.
Conclusion:
In conclusion, rounded aggregates require less cement paste for a given water content and lubrication due to their reduced surface area, smoother shape, and improved lubricating properties. This makes them a favorable choice for achieving good workability in concrete mixtures.