What's in the Display Case?

Liquid Limit Device

The liquid limit (LL) is the water content where a fine-grained soil changes from liquid to plastic behavior. Knowing the liquid limit helps to determine the soil’s compressibility, permeability and strength, and therefore whether an earth slope will be stable or whether a certain soil will support a building foundation, for example. To use this device, the technician places wet soil in the bowl. He or she cuts a groove in the soil, then turns the crank, which makes the bowl lift slightly then fall back down. The technician counts the number of times it takes the bowl to fall before the groove in the soil smooths out. The moisture content at which it takes 25 drops of the cup to cause the groove to close is defined as the liquid limit.

Liquid limit is only measured for silts and clays, not for sandy soils. Can you think why?

Previous Display: Settling Columns

The 7-foot-tall columns formerly displayed are settling columns, which are used to determine sediment settling properties. This equipment is used to evaluate the settling behavior of dredged sediments in a containment area. In other words, the columns help show how much water will remain in the sediments and how much will drain out. Column settling tests help determine how big to make an impoundment that will hold dredged sediment.

Hart Crowser’s laboratory is one of the few in the nation that offers a full suite of sediment quality tests, uses the most current US Army Corps of Engineers protocols, and interprets the data to help you in the permitting and design process. Our testing services are used to characterize sediment material for dredging, in-water management, and disposal projects.