A pneumatic or multi-tiered roller is most effective for compaction of which type of soil?

A pneumatic or multi-tiered roller is most effective for compaction of clay soils due to several key characteristics of clay. Clay has a very fine particle size and exhibits cohesive properties, which means it can be compressed and hold its shape quite effectively when compacted. The design of pneumatic rollers, which feature rubber tires that can apply varying pressures and adjust to different surface conditions, is particularly well-suited for achieving maximum density in clay. This type of roller can knead the soil and provide uniform compaction by distributing weight over a larger area, which is essential for clay's cohesive nature.

In contrast, sandy soils tend to drain quickly and do not hold moisture or shape well. Loamy soils, while they have good compaction characteristics, are typically less challenging than clay when it comes to achieving high-density compaction. Gravel soils, while effective with certain types of rollers, benefit more from vibratory rollers that can effectively move and rearrange the larger gravel particles. Therefore, for achieving optimal compaction results, a pneumatic roller is best utilized on clay soils where moisture control and cohesive strength can be maximized.