FAQs

The synthetic fibers currently being marketed as concrete reinforcement are nylon, polypropylene and polyolefin. The principle component of AR-glass fiber is silica, 62%. Other components include 19% of zirconia and 0.1% titanium.

Here is a comparison of the physical properties of AR-glass and other synthetics:

Property	Fiber Type
	AR -Glass	Nylon	Polypropylene/Polyolefin
Specific Gravity	2.68	1.14	0.91
Tensile Strength (psi)	245,000	140,000	70,000 - 100,000
Modulus of Elasticity (psi)	10,400,000	750,000	500,000 - 700,000
Strain at Break	3.6%

The specific gravity of the nylon fiber is 1.14 and the polypropylene and polyolefin are 0.91 whereas the AR-glass fiber is 2.68. Remember here that a principal component of AR-glass fiber is silica.

The most telling difference is Modulus of Elasticity where the nylon and polypropylene/polyolefin value will be in the range of 400,000 to 500,000 psi and the AR-glass has a Modulus of Elasticity of 10.4 million psi. This is a major and important difference.

The tensile strength of nylon is approximately 140,000 psi and polypropylene/polyolefin is in the range of 70,000 to100,000 psi. The tensile strength of AR-glass is approximately 245,000 psi, which exceeds that of steel.