To supplement field testing results, laboratory testing is required on samples properly acquired and retained from the drilling operations. This lab testing on soil and rock samples is used to correctly classify the material type and ascertain the nature, strength, and consolidation characteristics of the subsurface layers. Additional lab testing may be required at specific sites to determine swell potential, corrosion potential, permeability, and durability. Perform all laboratory testing in accordance with the relevant TxDOT, ASTM or AASHTO procedures.