Lightweight Insulating Concrete Using Pumice Aggregate

other cementitious applications for pumice in concrete

Pumice and Concrete: Other Cementitious Applications

1,500,000 pounds of US Grout Ultrafine SD was used when driving Intake Tunnel #2 beneath Lake Mead, successfully controlling water inflow for on-time completion.


Produced through our US Grout division and distributed globally by Avanti International, our microfine and ultrafine cementitious grout products are used to stabilize and strengthen soils and seal cracks as small as 6 microns in concrete structures and rock. Our pozzolanic grouts are a strong, economical, long-lived, safe-to-use alternative to chemical grouts.

The US Grout website outlines the development of this ultrafine cementitious grout by the Sandia National Laboratories (for the U.S. Department of Energy), details the various industrial applications for this multi-use grout, provides mixing instructions, and more.


LimeStrong plaster is the result of a partnership between the world-renowned natural plaster expert, Stan Petersen, and Hess Pumice, the source of key components in the LimeStrong natural plaster formulation: pumice pozzolan and lightweight pumice aggregate. With the additional of slaked lime and a few other performance-boosting ingredients, this classic formulation out-performs modern plaster equivalents and stands as an environmentally sound alternative to synthetic stucco and Portland-cement based plaster products.

What LimeStrong is NOT is a pure natural lime plaster (NHL) product, nor is it a cement lime product. That means we can formulate impressive performance characteristics—autogenous healing, flexibility, breathability, strength, durability—while holding the line on cost.

The LimeStrong website is loaded with information on installed square-foot costs, performance details, application tips, finish options, technical data, and an extensive photo gallery.

GFRC panels make the ideal lightweight canvas for imitating natural rock-scapes in interior spaces.


Glass fiber reinforced concrete (GFRC) products take lightweight mold-cast concrete and apply it on a grand scale. GFRC panels provide a beautiful architectural skin to protect building exteriors and finish interior walls and ceilings with fascinating, enduring detail.

GFRC is a Portland cement-based composite reinforced with randomly dispersed, alkali-resistant glass fibers, with those fibers adding strength—impact, tensile, and flexural—to the concrete.

With GFRC surfacing panels, the balance between weight, strength, and durability is a delicate one—bright, hard, lightweight Hess pumice aggregate and Hess Ultrapozz (superfine pumice pozzolan) make it all work to impressive advantage.

Weight: Hess pumice aggregate is lighter than sand and has an additional advantage of being the whitest pumice on the market.

Strength and Durability: Concrete is inherently strong and durable, and the addition of the glass fibers adds to that functional strength when used in a thin-panel application, but like any construct or product that uses Portland cement, a congenital performance vulnerability in the cement and water hydration reaction must be accounted for in the mix design. And of further concern for the GFRC industry is the loss of strength and ductility from the interaction of alkalinity in the hydrated cement paste with the very glass fibers used to provide the concrete composition with its multi-faceted strength. These deleterious effects are overcome by using a ultrafine pozzolan in the mix design. But not just any pozzolan will do.

Case in point: Nippon Electric Glass (Japan) and NEG America, a world-wide provider of materials and support to GFRC panel manufacturers, selected the performance advantages of Hess Pumice and entered into an agreement as the exclusive distributor of Hess UltraPozz to the GFRC industry.