1. n. 
A chemical with the formula NaHCO3. It is called bicarb at the drilling rig and is used to treat cement contamination in water mud. When cement hydrates, substantial amounts of lime, Ca(OH)2, are produced. As the cement sets, less free lime is available. When partially set cement is drilled with a water mud, Ca+2 and OH- ions are leached into the mud, often causing problems associated with clay flocculation and polymer precipitation. Bicarb can be added, either as a pretreatment or over a period of time, to remove the Ca+2 in the form of insoluble CaCO3 while simultaneously neutralizing OH- ions with the H+ ion in the bicarb molecule.