How is the aggregate moisture content calculated?

The calculation of aggregate moisture content is essential for understanding the amount of water present in the aggregate, which can significantly affect the performance of concrete mixtures. The correct formula for calculating moisture content involves determining the difference between the total dry mass (TDM) of the sample and the oven-dry mass (OSM), then dividing that difference by the total dry mass and multiplying by 100 to express it as a percentage.

By using the formula (TDM - OSM)/TDM x 100, you are effectively measuring the water weight in relation to the total weight of the dry aggregate. The total dry mass represents the weight of the aggregate with no moisture, while the oven-dry mass accounts for the weight of the aggregate after all moisture has been removed. This comparison allows for an accurate assessment of how much moisture is present relative to the dry mass, which is critical for maintaining the desired water-to-cement ratio in concrete production.

The other options do not correctly represent the relationship needed to calculate moisture content in a way that aligns with established standards and practices. They either do not properly differentiate between the weights or fail to yield the correct percentage of moisture in relation to the dry aggregate.