Lightweight Pumice Aggregate and Sand

UMICE CONCRETE is composed of Portland cement, pumice stones, pumice sand, pumice powder (pozzolan), and water. Compared to standard concrete, pumice concrete offers roughly a one-third reduction in weight and four times the r-value. Proportioning, mixing and placing are done in a similar manner to that of standard concrete. (Download our Mixing and Placing Pumice Concrete Tip Sheet) Pumice concrete is placed and finished with typical concrete equipment and tools and is used, with one exception, for the same applications as sand and gravel concrete. That exception: due to the grippy nature of pumice aggregate and sand, pumice concrete takes more effort and patience to work to a standard surface finish, and for that reason is rarely used for extensive flatwork. But for limited flatwork projects and all applications where pumice concrete is vibrated into forms, (like precast applications) it presents no placement challenges beyond standard concrete and actually presents several advantages. (Download Pumice Concrete Mix Designs)

Pumice concrete has superior resistance to harsh weather conditions like freezing and thawing and an R-value some four-times that of ordinary sand and gravel concrete—making pumice concrete ideal for colder climates and locations that experience dramatic fluctuations in the weather and temperature. Pumice concrete is also sound absorptive, more elastic than conventional concrete, and will not spall under direct contact with flame.

Pumice is a porous, naturally-occuring volcanic glass, riven with air-filled vesicles formed by the expansion of trapped gasses when the molten lava is expelled into the air and flash-cools. It is this amorphous, cell-filled nature of each stone that give pumice it’s lightweight and insulative characteristics. Pumice is also an inert material and therefore will not react with the reinforcing steel or any other concrete component.

For additional information on pumice-based lightweight insulative concrete, visit our Pumice and Concrete website.