What class of stones for riprap ranges from 60 kgs to a maximum of 100 kgs with at least 50% weighing more than 80 kgs?

The correct classification for riprap stones that weigh between 60 kgs and a maximum of 100 kgs, with at least 50% of the stones weighing more than 80 kgs, is Class C. Riprap is commonly used for erosion control, and specific classes are defined by the size and weight of the stones used.

Class C is identified by its specific weight range, which adheres to the requirement of having a mix where a considerable portion exceeds 80 kgs—this size ensures adequate resistance to erosion in the applications for which riprap is intended. The designated weight limits for Class C make it suitable for various environmental conditions where protections against water flow or weathering are necessary.

Understanding these classifications is crucial for engineers when designing structures that will be exposed to hydraulic forces, ensuring the appropriate materials are selected for stability and longevity in such applications.