Question

How the moisture content of the aggregates obtainable at site affects the water content ratio specified?​

Answer 1

Answer:

Aggregate Moisture in Concrete

Answer 2

The moisture content of the aggregates obtainable at site affects the specified water-content ratio in the following ways.

• If the aggregates are in a surface wet condition (the moisture content is greater than the absorption) then it causes an increase in the water-to-cement ratio.
• Increased water content ratio reduces the compressive strength and durability of the concrete.
• The increased content of water leads to a higher water-to-cement ratio.
• The high humidity levels increase the concrete’s pH and temperature. An increase in pH levels decreases the adhesive bonds between aggregates and  higher temperatures allow concrete to dry faster, resulting in a less structured, more porous product.
• High moisture content also results in microbial growth in the concrete.
• The bicarbonate ions and carbon dioxide causes carbonation in concrete and reduces its strength.
• Higher water-to-cement ratios affect the compaction of the aggregate, as they result in greater spacing between the aggregates in cement.
• To ensure constant moisture content in aggregates the following conditions should be met.

1. Area of each aggregate pile should be large.

2. Height of each aggregate pile should not exceed 1.50 m. 3. Aggregate piles should be left for 24 hours, before the aggregates are used.

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