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The Roman Pantheon, constructed using pumice concrete in 126 A.D.
The high R-value of pumice concrete makes it ideal for exterior wall applications.
Pumice aggregate makes stone and brick veneer products lightweight and versatile.
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PUMICE CONCRETE BROCHURE
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pumice concrete & blocks
There's nothing new about pumice concrete. The Romans were using it over two millennia ago. Roman engineers have been celebrated for their enduring wonders—especially for the most well-preserved of all Roman architecture, the Pantheon of Rome. Modern scientists, some 2000 years after its construction, have determined that the secret to Pantheon's longevity is pumice (known as pozzolana to the Romans). How Roman engineers determined the pozzolonic qualities of the pumice aggregate is yet a mystery. What is not a mystery is the enduring qualities of the world's most perfect aggregate, lightweight or otherwise.
Today's pumice concrete is composed of portland cement, pumice rock, pumice sand, and water. It is proportioned, mixed, and placed in a similar manner as conventional sand-and-gravel concrete, is used in the same applications, and is placed, screed, troweled and finished with the same equipment.
Hess pumice concrete has several advantages over conventional concrete in many construction applications:
LIGHTWEIGHT concrete
The most significant of the advantages of pumice concrete is its lightweight quality—up to one-third lighter than conventional sand-and-gravel concrete. This trait contributes to a decrease in structural steel costs and, consequently, job costs. Larger volumes of concrete can be handled by lighter equipment with less wear and tear on the equipment.
The reduction of deal load on structural supports, trusses, girders and slabs can allow extra stories on buildings where dead load is a governing factor.
Lightweight Hess pumice concrete also reduces the live load on formwork and falsework.
WORKABILITY
Another key factor is workability, particularly in nailing, sawing, and drilling. As for appearance, pumice concrete has a uniform color and texture.
Low conductivity
The lower thermal conductivity of pumice concrete provides less heat loss. Hess pumice concrete has 4X the R-value of regular aggregate concrete. This both slows heat transfer and eliminates or reduces moisture condensation on walls and ceilings.
Pumice concrete delivers a higher fire rating that standard concrete and will not spall under contact with direct flame.
Acoustical ratings are higher for pumice concrete as well.
durABILITY
Finally, pumice concrete has superior resistance to harsh weather conditions like freezing and thawing. This, plus its high R-value, makes pumice concrete suitable for colder climates and dramatic changes in weather.
Hess pumice concrete is more elastic, for reduced brittleness under earthquake conditions.
The superior water absorption/desorption characteristics of the pumice means that the moisture held in the interior of the pumice aggregate is not immediately available for chemical interaction with cement, but is extremely beneficial in maintaining longer periods of curing, giving better strength and reduced permeability in the final concrete.[ASTM technical publication 169C]
Pumice Concrete Blocks
Pumice concrete blocks are lighter to lift and place and mean less deadweight loads...and still meet compressive strength requirements.
Blocks made with Hess pumice produce a lightweight concrete structure that is the whitest masonry available. This block is popular for commercial, professional, and residential buildings and for decorative uses such as fireplaces, planters and walls.
The pumice alone, with its exceptional insulating properties, is also used as a cavity fill for concrete block walls.
Pumice Stone and Brick Veneer Products
Pumice aggregates are used extensively in the production of stone and brick veneer products, like Owens Corning's Cultured Stone®. Pumice makes the ideal aggregate: it can be sized for any needed mold shape, provides bulk and strength yet results in a lightweight product that can be used as interior and exterior finishes without additional supporting ledges. And the consistent clean white color of Hess pumice means the color of every manufactured stone or brick starts and finishes rich and vibrant.
