Duffield Associates operates one of the Mid-Atlantic region's largest privately owned materials testing laboratories. This extensive facility combines a full range of testing equipment with isolated and conditioned environments required for precise test protocols.

Our full-service soils and concrete testing laboratory, complete with an environmentally conditioned room for the storage and curing of concrete compression test cylinders, is accredited by the American Association of State Highway and Transportation Officials (AASHTO) and approved by the U.S. Army Corps of Engineers.

Services provided include:

• Soil Index Testing
  Tests include soil gradation, specific gravity, and plasticity, among others, which are used to classify soils and estimate their engineering properties.
  
  
• Consolidation Testing
  Provides a means of determining the time rate and potential magnitude of settlement of fine-grained saturated soils following stress application.
  
  
• Direct Shear and Triaxial Shear Testing
  Determines soil strength parameters including angle of internal friction and cohesion. Testing can be performed on undisturbed or remolded samples to simulate anticipated design stress conditions.
  
  
• Flex Wall and Rigid Wall Permeability Testing
  Measures permeability or hydraulic conductivity of granular or fine-grained water saturated soils.
  
  
• Concrete and Mortar Testing
  Determines the compressive strength of cementious materials including concrete, cement amended flyash, grout, and mortar.
  
  
• Proctor Testing
  Determines the maximum dry density and optimum moisture of soils utilized in construction.