THE SYNERGY between Portland cements and pumice aggregate, pumice sand, and pumice pozzolan delivers an impressive array of benefits in a variety of applications. And the combination of slaked lime and fine-ground pumice make sweet music in the form of beautiful lime plasters and breathable, sustainable hempcrete constructs.

Ultrafine Cementitious Pozzolanic Grouts

Microfine and ultrafine cementitious injection grouts, performance-boosted with pumice pozzolan, are enduring, cost-effective alternatives to chemical grouts and used in a variety of construction applications to stabilize and strengthen weak soils. Ultrafine cementitious grouts are also used to effectively seal cracks as small as 6 microns in concrete structures and rock, preventing water infiltration and blocking exfiltration into storage vaults containing volatile materials (nuclear waste) or valuable liquids (crude oil). Pozzolanic-charged grouts are a strong, economical, long-lived, and safe to use.

Visit the US Grout site for a detailed look at a pozzolanically charged ultrafine cementitous injection grout product line. Of particluar interest is the story of the development of this ultrafine cementitious grout by Sandia National Laboratories (for the U.S. Department of Energy). The US Grout site also details the various industrial applications for this multi-use grout, provides mixing instructions, and more.

Pozzolanic Hydrated Lime (PHL) Plasters

Natural PHL plasters are a blend of pumice pozzolan powders and lightweight pumice sand particle blends with high-grade slaked lime and other performance-boosting ingredients. It is a classic formulation that out-performs modern plaster equivalents and stands as an environmentally sound alternative to synthetic stucco and Portland-cement based plaster products. PHL plasters are the only option to finish wall systems designed to breathe—strawbale, hempcrete, adobe brick, and other earthen materials. Some commercial insulated concrete form (ICF) wall systems, like Faswall^®, specify a lime plaster render to preserve the featured breathablity of the structure.

To be clear, a PHL-type (pozzolanic hydrated lime) plaster is NOT a pure natural lime plaster (NHL) product (typically imported from Europe), nor is it a cement lime product. PHL plasters are formulatd for impressive performance characteristics—autogenous healing, flexibility, breathability, strength, durability—while holding the line on cost.

Visit the Earthaus Plaster site for a detailed look at a well-developed PHL plaster product line.

Lightweight Stuccos and Bonding Mortars

Pumice-based mortars and stuccos not only meet installation, performance and bonding requirements, they play the long game too: like bonding like. Meaning the pumice aggregates that bulk up the stuccos and mortars are the same lightweight aggregate used to make the cast-stone veneer pieces being bonded. Meaning the mortar reacts to climate and weather conditions (like freeze-thaw stresses) in the same way as the veneer units themselves. Meaning less weight-stress on the supporting substrate and structure from both veneer and mortar. Like bonding like.

Lightweight stuccos and mortars represent a unique combination of proven performance and welcome safety benefits for masonry crews. The bags of lightweight material are easier to safely move, lift onto the mixer deck, and work with day after long day. No respirable crystalline silica means no worries about long-term health issues working around mortar dust on the jobsite.

Lightweight bonding mortars and stuccos meet the demanding and diverse needs of today’s professional, from mortars for typical needs—laying up a block wall or laying down a tile surface—to meeting the more nuanced bonding requirements of the ever-growing variety of manufactured stone, brick, and board-like veneer products.

Visit the HessLite Blended Products site for a detailed look at a product line of pumice-based bonding mortars, construction mortars, and stuccos.

Glass Fiber Reinforced Concrete (GFRC) Panels

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 panel.

With GFRC surfaced 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.

Download a PDF of the whitepaper: Ultrafine Pumice Pozzolan for Glass Fiber Reinforced Concrete Products.

LINKED RESOURCES

—Download the Whitepaper: Ultrafine Pumice Pozzolan for Glass Fiber Reinforced Concrete Products.

—Visit the US Grout website.

—Visit the HessLite Blended Products website.

—Visit the Earthaus Plaster website.