Ageing mechanisms of GRC composites

The changes in the properties of the GRC composite during ageing, and in particular the loss in toughness (i.e. embrittlement) are an extremely important characteristic of this material. This problem is a central one for the application of GRC in the construction industry, and it is dealt with at two different levels  

1 Development of composites of improved durability performance using modified glass and matrix formulations. 

2 Design of GRC components taking into account the changes in properties during ageing. 

These two topics will be further discussed in Sections 8.6 and 8.7. However, a comprehensive treatment of these two aspects requires a more detailed analysis of the processes which lead to this change in properties. 

It is now well established that the ageing of GRC cannot be simply attributed to al kal i attack of the glass fibres by the highly alkaline cementitious matrix. Two mechanisms must be considered to account for the reduction in strength and loss in toughness of this composite  

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