Experimental Study On Bond Behavior Between Fiber Ceramsite Concrete And FRP Rebar

The structure of the external walls of the building is significant,and the corrosion of steel bars and the poor insulation performance are still unsolved.Replacing materials is one of the most effective solutions at present.Through research,it is found that lightweight concrete such as ceramsite can not only reduce the weight of the structure,but also reduce the weight of the structure.Moreover,the advantages of thermal insulation can be exerting.In addition,the FRP bar is used instead of the steel bar to avoid corrosion caused by corrosion of steel bar.Some studies have shown that adding polypropylene fiber into ordinary concrete can effectively improve the tensile strength of concrete.Therefore,adding proper amount of fiber into ceramsite concrete can improve the mechanical properties of ceramsite concrete wall.The new wall panels should be widely applied in engineering practice.There are two major problems to be solved.The first is the seasonal cooling and heating alternation problem in the use of the wallboard.The quality loss and strength loss directly relate to the service life of the wallboard in the freeze-thaw condition.However,there is still no data support for quality loss and strength loss in the current research results.Second is the problem of bond between FRP tendons and fiber ceramsite concrete.The bond strength is not yet clear in terms of strength grade,anchorage length,reinforcement type and diameter of steel bar.The freeze thaw test and pull-out test have provided theoretical support for the collaborative work of the two,and the main contents are as follows.(1)Design of 144 pieces ceramic concrete cube blocks with a size of 100mm,and to test the strength of the polypropylene fiber mixed with 0.9%%m polypropylene in the test block.The strength and loss of part of the test piece are measured on the third,seventh,fourteenth and 28 days of standard curing.Both mass loss and strength loss are proportional to freeze-thaw cycles.(2)Design of 144 fiber ceramsite concrete specimens were designed according to the strength grade,anchorage length,reinforcement type and diameter of reinforced concrete.The accurate pull-out force and slippage were obtained through the pull-out test,the bond anchorage curve was drawn up,and the bond slip constitutive relation model of fiber reinforced concrete and fiber ceramsite concrete was established,and each stage of the model was analyzed.With the increase of bond anchorage length and diameter,the bond stress decreases,and the bond stress increases with the increase of concrete strength.