Massachusetts Construction Supervisor License (CSL) Practice Test

Dense gravel has the greatest allowable bearing pressure among the materials listed because it has superior load-bearing properties due to its high density and compact nature. The angular particles in dense gravel interlock effectively, creating a stable, strong foundation that can support significant structural loads. Additionally, dense gravel typically has good drainage characteristics, which helps prevent issues like water accumulation that can weaken foundation support.

In contrast, foliated bedrock like slate, while generally strong, may have internal weaknesses along the foliation planes that can reduce its effective bearing capacity, particularly if the layers are not horizontal or if there are fractures within the bedrock. Stiff silty clay can provide reasonable support but is more susceptible to changes in moisture content, leading to potential issues with swelling or shrinkage that can affect its load-bearing capacity. Dense glacial till, while also a strong material, does not usually match the strength and load distribution characteristics of dense gravel, making it less favorable in terms of allowable bearing pressure.