Gypsum and Screed Products

Gypsum plaster can cause problems by cracking in the first hours after hardening due to a lack of elasticity, and workers in Spain have evaluated the use of waste tyre rubber to reduce the possibility of this occurring by reducing the elasticity modulus of the set plaster [62]. Their study analysed the mechanical behaviour of gypsum plaster that contained rubber particles of three different sizes (0-1,1-2 and 

2-4 mm) at three different volume fractions (1,3 and 5%). The results were compared with those for gypsum without any rubber modifier. 

WRAP [63] has also funded a project that uses rubber from waste tyres to product new flooring screed and plaster products. The products are generically known as Rubbercrete, with the plaster products containing 70% rubber crumb and the flooring screed 30% crumb. Rubbercrete is also available in a rapid set mix design, which has a crumb content of 35% and dries within two to three hours. 

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