Investigation of usability of various engineering polymers as rock bolt material

In this study, three different kinds of polymer materials (Polyurea, PP-R, Poliyamide-6) were investigated to be used as rock bolt materials. Grouted rebar and split-set types of rock bolts were easily coated with polymer spraying. The experimental studies on use of polyurea coated rock bolts were performed under acidic underground water conditions. Long and short terms pull-out tests were performed on polymer coated and uncoated rock bolts separately to examine the effect of the surface treatment method on rock bolt corrosion. It was observed that polyurea layer prevented steel corrosion economically while bolt load bearing capacity was being increased significantly. Tubes made of Polypropylene random copolymer (PP-R), another polymer material used in this study were assessed with a series of experimental study including laboratory and field tests to use instead of steel split sets, in terms of prevention of the corrosion problem. PP-R tubes and typical steel split sets were comparatively investigated with statical loading (pull and shear), dynamic (impact) loading, creep, corrosion, diametral compression and insertion tests. PP-R tubes having proper chemical resistivity and mechanical properties, advantages of being shaped by the roughness of the drillhole surface making the friction coefficient be high were assessed to be usable as frictional rock bolts in rock engineering. According to the data obtained with this study, it is suggested to develop new rock bolt products to use PP-R tubes instead of steel split sets. Polyamide-6 type engineering polymer whose the support characteristics were determined in this study was assessed to have a high body strength and adherence in the cement mortar grouts. As outcome of the study performed on the Polyamide-6 type engineering polymer, new mechanical anchored and grouted rock bolts were designed. Polyamide-6 rock bolts seen to exhibit ideal support reactions under both static and dynamic loads are suggested to start being systematically applied in mining.