Rubber Particles from Recycled Tires in Cementitious Composite Materials

Abstract

In the present study, the influence of the shape of rubber particles on mechanical properties of mortar was examined by using rubber granules of about 2 mm in diameter (GR 2) and two sizes of fibrous rubber (one being about 5.5 mm long and about 1.2 mm diameter, and the other being about 10.8 nun long and about 1.8 mm in diameter). The rationale for using fiber-shaped rubber particles is that the addition of fibers (steel, glass, carbon, polypropylene) to concrete has resulted in concrete which is less prone to brittle failure and to plastic shrinkage cracking (15-17). For convenience, in this exploratory study, mortar was used instead of concrete in the belief that the effects on mortar and concrete would be similar. As expected, this study confirmed the findings of previous work that granular rubber decreases compressive and flexural strengths. An encouraging discovery was that plastic shrinkage cracking can be reduced by the addition of sufficient fibrous rubber. Further investigations are required to verify that similar benefits can be obtained by adding rubber to concrete.