What is Glass Reinforced Concrete

BCM Glass Reinforced Concrete (GRC) is a thin section concrete that uses Alkali Resistant glass fibres for reinforcement as opposed to traditional steel. The fact that the fibres will not rust like steel means that there is no real requirement for “cover” and no problems associated with the lack of it. As such it is possible to make lightweight elements that have impressive structural qualities yet save up around 65-75% of the weight of a solid unit. BCM have been making “quality assured” GRC since the early 1980’s

How Strong Is GRC?

The table on the left gives typical figures for the mechanical properties of BCM GRC. As can be seen, the compressive strengths are better than normal concrete, the impact strengths are good, but the real benefits are gained from the fact that GRC functions in bending. This enables designers to make strong hollow lightweight components.

How Will GRC Weather?

Where BCM GRC products have a stone faced finish this is very similar to wet cast concrete and can be expected to weather much the same. The integral face mix of BCM GRC products is comparable to that of large pre-cast cladding although a lot thinner with smaller aggregates. Semi-dry concretes (used mostly for domestic construction) by comparison, have very low cement contents and open textures that retain atmospheric pollution and deteriorate very quickly. In practice, the design of the element and the local environment has a strong effect on how any cladding stands the test of time. Evidence from architectural GRC that has been around for 20 or more years suggest that the weathering characteristics are as good as any pre-cast material and better than semi-dry products. There are several projects in London that combine natural stone, wet pre-cast and GRC that demonstrate how well GRC blends in with more “traditional” materials.

How Can I Specify GRC?

GRC is normally specified by reference to the “Specification for the manufacture, curing and testing of GRC products” as produced by the Glass Reinforced Concrete Association (GRCA). Standard NBS section H40 contains similar information as does EN 1169 and EN 1170. Specifiers are encouraged to use manufacturers that comply with the “Approved Manufactures Scheme” audited independently by the GRCA. BCM GRC are the most experienced manufacture of GRC in the UK.