WORLD CIVILIZATION

Detailed explanation-1: -Romans made concrete by mixing volcanic ash with lime and seawater to make a mortar, and then incorporating into that mortar chunks of volcanic rock, the “aggregate” in the concrete.

Detailed explanation-2: -The Romans made concrete by mixing lime and volcanic rock. For underwater structures, lime and volcanic ash were mixed to form mortar, and this mortar and volcanic tuff were packed into wooden forms.

Detailed explanation-3: -Roman concrete consisted of a mixture of a white powder known as slaked lime, small particles and rock fragments called tephra ejected by volcanic eruptions, and water.

Detailed explanation-4: -The designation pozzolana is derived from one of the primary deposits of volcanic ash used by the Romans in Italy, at Pozzuoli. The modern definition of pozzolana encompasses any volcanic material (pumice or volcanic ash), predominantly composed of fine volcanic glass, that is used as a pozzolan.