GRC Guide

Glass fibre Reinforced Concrete (GRC or GFRC) is a cement-based composite material reinforced with alkali-resistant fibres.

GRC can be formed into thin sectioned lightweight elements and provides designers, architects and engineers with substantial advantages when compared to other traditional concrete materials.


GRC is used worldwide to manufacture a vast range of precast products for the building and civil engineering industries.

The fibres add flexural, tensile and impact strength and the resulting material allows the production of strong, yet lightweight, products used in architectural, civil engineering and many other applications.

The properties of GRC vary according to the production method, mix design, and the type and content of the Alkali Resistant Glass Fibre.

Traditional Spray can produce the highest strengths due to a high AR Glass fibre content, low water/cement ratio, long fibre length and planar fibre orientation.

Premix Strengths are generally lower than those of the Traditional Spray method due to lower AR Glass fibre reinforcement contents, higher water/cement ratios, shorter fibre lengths and 3-dimensional fibre orientation.

Sprayed Premix gives consistent mechanical properties similar or higher than those obtained with vibration cast premix.

Typical Mechanical Properties

Property Units Hand Spray Premix

Fibre Content

Wt.% 4 – 5 1.5 – 3.5

Density (dry)

g/cm³ 1.8 – 2.1 1.8 – 2.1

Flexural Strength      LOP

N/mm² 6 – 10 5 – 10

Flexural Strength      MOR

N/mm² 18 – 30 5 – 15

Compressive Strength

N/mm² 40 – 70 50 – 80

Tensile Strength       UTS

N/mm² 8 – 12 3 – 6

Tensile Strength       BOP

N/mm² 4 – 6 3 – 5

Thermal Conductivity

w/m°C 0.9 – 1.5 0.9 – 1.5

Thermal Expansion Coefficient

x10-6/°C 7 – 12 7 – 12

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