Saturated-surface-dry

Saturated surface dry (SSD[citation needed]) is defined as the condition of an aggregate in which the surfaces of the particles are "dry" (i.e., surface adsorption would no longer take place), but the inter-particle voids are saturated with water. In this condition aggregates will not affect the free water content of a composite material.[1][2]

The water adsorption by mass (Am)) is defined in terms of the mass of saturated-surface-dry (Mssd) sample and the mass of oven dried test sample (Mdry) by

${\displaystyle A={\frac {M_{ssd}-M_{dry}}{M_{dry}}}}$