was released after ACI 440.6-08 was published so basalt was not specifically mentioned. ASTM testing of RockRebar®
indicates that continuous basalt fiber in epoxy polymer materials exceed those of silica based fiberglass and easily meet American Concrete Institute (ACI) minimum performance requirements.
Recommendations for maximum deflection and shear of concrete elements reinforced with fiber reinforced polymer (FRP) rebar's are presented in ACI 440.1R-06 (2006), Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars.
Generally, the design methodology for FRP-reinforced concrete members follows that of steel reinforcing, however designing concrete structure to exploit the non corrosive and light weight attributes of FRP reinforcement must take into account the linear elastic or non-ductile nature of these material by using an FRP material reduction factor, and controlling the stress and strain at the serviceability limits for a given structure.
RockRebar® mechanism for failure being either rupture of the reinforcement itself or crush of the concrete.
A direct substitution of RockRebar® into a concrete member that was designed for steel rebar may not be possible.
While RockRebar® is several times stronger than steel it may be necessary to redesign the size and placement of RockRebar® within the concrete member to mitigate to potential for excessive deflection of the panel or beam.
A RockRebar® reinforced concrete member should be designed to accommodate its required strength keeping in mind the stress-strain relationship exhibited by all FRP reinforcements is differant that rusty steel.
RockRebar® is based on continues basalt fiber reinforced epoxy polymer BFRP. As such exhibits linear stretch up to failure.
Incompliance with the ACI 440.1R-06 (2006) all FRP reinforced concrete elements including RockRebar® should be engineered so that sustained stress is kept below 25% of its guaranteed tensile strength.
The physical strength of RockRebar® rods from 4 mm to 25 mm diameters rods change as the diameter goes up, with smaller diameter rods generally having higher tensile strength. Typical examples are shown below.
Nominal Diameter in inch, mm and #
200 meters =
Weight per 39'6" length
= (12 meters) lbs.
200 meter coil
Mpa & ksi
Guaranteed design tensile strength ASTM Mpa & ksi
GPa & ksi
|inch, mm and #||Mpa ksi||Mpa ksi ||GPa ksi |
21. lb / 9.5 kg
1.2 lbs / 0.54kg
0.25 = 6mm = #1
33.5 lb/ 15. kg
2.1 lbs / 0.953 kg
|.315 = 8mm = #2|
52.5 lbs 23.8 kg
3.25 lb /1.474 kg
|.393 = 10mm = #3|
86 lbs / 39 kg
4.85 lbs / 2.2 kg
0.472 = 12mm =#4
143 lbs/ 64.8 kg
9.47 lbs / 4.3 kg
0.63 = 16mm = #5
18.37 lbs/ 8.33 kg
"RockRebar®", is a "GREEN" sustainable and renewable product.
Notes on comparisons:
Concrete(10.15 x 10¯⁶/°C )
(5.7 x 10¯⁶/°F )
(6.2 x 10¯⁶/°C )
(Lenght Wisex 3.5x10¯⁶/°F )
Steel (11.5 x 10¯⁶/°C )
(6.35 x 10¯⁶/°F )
yield strain of 60 series= 0.020
Notice RockRebar® always has slightly less thermal expansion than concrete.
Steel always has more allowing micro cracks and moisture intrusion
density of concrete is about 2.5g/cm3
RockStaples are 2.8g/3cm3 so they mix and stay mixed very well
No measurable creep if sustained load is less than 40% of tensile rating
Strain at break 0.0315 in 2.8 g/c
Water absorption 72 hours @ 65 C is 0.02%
Thermal heat transfer W/m degrees C 0.031- 0.034
Glass temperature @ formation of fiber 2650F 1454C
Dimensional Stability at 200 C 392F 96%
density of is 1.9 (g/cm?)
Glass transition temperature of our preparatory epoxy adhesive matrix in production is 475F=(246°C)
Coefficient Thermal Expansion
(Lenght Wise 3.5 x 10¯⁶/°F )
(Across RockRebar 13.2 x 10¯⁶/°F)
(Lenght Wise 6.2 x 10⁶/°C )
(Across RockRebar 23.8 x 10¯⁶/°C)
Thermal conductivityW/m degrees C 0.036
Average strain at rupture for 1/2" (#4) in./in.(0.019)
Compressive strength more than = 500 MPa
Nominal Bond strength MPa = 19.8
Nominal Bond Strength PSI = 2872
The fibers analyzed are basalt, E-glass, boron free E-glass and AR-glass.
The samples tested were unidirectional fabrics having the same surface density of (300 g/m2).
The standard test method used for the accelerated aging testing alkaline solution is the one described in
After conditioning, specimens are well rinsed in distilled water and dried for 7 days in the same controlled laboratory conditions.
The specimen’s weight was measured both before and after the aging in order to evaluate fibers weight loss.
12 samples average value 3.87 % St. Dev. 0.57
12 samples average value 3.00 % St. Dev. 0.94
6 samples average value 2.01 % St. Dev. 0.32
12 samples avarage value 1.04 % St. Dev. 0.44
stability after 3 hour boiling H2O is 1.6%
stability after 3 hour boiling 2N NaOH is 2.8%
stability after 3 hour boiling 2N HCI is 2.2%
It is interesting to underline that E-glass fibers presented the greatest weight loss, of 3.87% (as average value), while basalt fibers presented the lowest one loosing only 1.04% of it`s volume after 28 days in pH=14 sodium hydroxide aqueous solution.