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Stromberg GFRC: Typical Properties
| Property | Unit of Measure | ASTM | 1/2" GFRC |
|---|---|---|---|
| Flexural Strenth | psi | C947-81 | 1,200 to 1,800 |
| Indention Strength | psi 1" dia. disc at 0.02" indent | D2394 | 2,700 |
| Water Absorption | % by weight 24 hrs. | C473-84 | 7 |
| Freeze-Thaw Resistence | Procedure B, number of cycles with no deterioration | C666-84 | 200 |
| Thermal | "R"/k value | C177 | .024/1.91 |
| Surface burning characteristics | Flame/smoke | E84-84 | 5/5 water vapor |
Stromberg GFRC can be used in both interior and exterior applications.
GFRC provides a high compressive strength, good surface hardness (impact resistance), and low coefficients of thermal expansion.
Highly moisture resistant, Stromberg GFRC will not rot, disintegrate or swell when exposed to water or completely submerged in water. It can be used for 100% under water applications.
GFRC is vapor-permeable and highly moisture resistant, but, as with most cement or masonry based materials, it is not intended as a water barrier. Water can potentially enter the system through openings, penetrations and joints. A separate waterproof membrane or moisture barrier must be used if the area behind the GFRC is to be kept dry.
Laboratory tests have shown that no signs of moisture would appear on the inside of a 1/2" sheet of GFRC with a wind blown rain at 75 mph.
Water vapor permeability ranges are generally below 3 perms. Air permeability of GFRC ranges from 4.6 perm-in for GFRC exposed to 40% relative humidity to 0.2 perm-in. for GFRC exposed to 90% relative humidity.