Bonding of Steelbolts to Concrete by UKA 3 — Technology

Research into the bond and durability of polymer-mortared studs was carried out according to the UKA 3 technology method. The studs were also exposed to extreme weather conditions and chemical influences as well. In the pull-out-tests 18-years old bolts had a shear failure between the mortar and the steel stud. The shear strength after 8 1/2 years of weathering reached an average value of 14,5 N/mm2 which corresponds to the average value of bond strength reached after one day of curing.The bond specimens that were sustained under a steady load and cured in alkalic concentrated water for over a period of 8 1/2 years showed a larger slippage in the bond than those cured under dry condition, the strength, however, was the same.Moreover it was found that cracks of 0,3 mm in concrete caused a strength reduction of 50% for studs of 20 mm in diameter and 80% for studs of 10 mm in diameter.