The hygroscopic moisture is calculated as a percentage of what?

Hygroscopic moisture refers to the moisture that is found in the soil, which is adsorbed onto the surface of soil particles. This moisture is not free water that can drain away; instead, it is tightly held by the soil particles. The correct way to calculate hygroscopic moisture is as a percentage of the mass of dried soil.

When you take the mass of the dried soil, you can determine the amount of moisture that was lost during the drying process. By comparing the weight of the water lost to the original dry mass of the soil, you can express hygroscopic moisture as a percentage. This relationship allows for an accurate representation of how much moisture is associated with the soil particles themselves, independently of any additional wet mass from free water or other sources. Understanding this calculation is essential for evaluating the moisture content in various soils, especially in construction and agricultural practices.