Improved Performance of Rock Bolts using Sprayed Polyurea Coating

Abstract

Cost of Polyurea Coat The deficiencies in tunnel supports led to improvements, including the use of new materials. Because underground water can substantially affect steel materials and decrease their load-bearing capacity, especially for long contact times and acidic water conditions, researchers have been trying to find economical ways to solve the problems of steel corrosion for many years (Ranasooriya et al. 1995; Li and Lindblad 1999; Komurlu 2012; Hassell and Villaescusa 2005). The application of a polyurea-type thermoset polymer coating was assessed in this study. Polyurea is an isocyanate-based copolymer used for surface treatment applications, such as liners for truck beds, tanks, ships, buildings, pools, and waste deposition isolation plants, beacause of its good water-resisting performance (Komurlu and Kesimal 2012). In addition, it is becoming popular for application on sewage walls because of its resistance to chemical degradation from sulphuric acid and hydrogen sulfide gas (Muynck et al. 2009). Polyurea is being used as spraying membrane in tunneling and a support called thin spray-on liner (TSL) (Tannant 2001). It is known that polyurea has good adhesion with rock, concrete and steel surfaces (Ozturk and Tannant 2010; Ozturk 2012; BASF 2009). Polyurea polymerizes owing to the chemical reaction between two liquid ingredients. The liquid phase time of mix can be chosen in accordance with the type of product. The material used in this study is immediately activated within two or three seconds after being blown out of the sprayer gun nozzle. To test the load-bearing capacities of polymercoated rock bolts (PCRBs) and the corrosion prevention performance of the polyurea coating, a copper mine in the northeastern region of Turkey was chosen as the case study area.