What is the result of a decrease in moisture content in expansive soils?

A decrease in moisture content in expansive soils leads to a decrease in volume or shrinkage. Expansive soils, often referred to as shrink-swell soils, have clay minerals that readily absorb water, causing the soil to swell. Conversely, when moisture is removed or decreases, the expansive clays lose their water, which results in the reduction of the soil particles' volume.

This shrinkage can lead to significant changes in the soil structure, creating issues in built environments, such as foundations, roads, and other structures. Recognizing this behavior is crucial for proper engineering and construction practices when dealing with expansively swelled soil conditions. Therefore, understanding that a decrease in moisture content signifies shrinkage effectively encapsulates the behavior of such soils.