Experimental Study On The Green Strengthening Method Of Prestressed CFRP Plate

The academia and engineers are vigorously promoting the concept ofGreen Building Structure, which means the building materials,construction and normal service could save nature resources, protect theecological environment and reduce pollution, achieve sustainabledevelopment between the natural environment and social environment.Strengthening with pre-stressed carbon fiber reinforce plastic plate(P-CFRP) is a new and green strengthening technique developed inrecent years, which different from bonding carbon fiber reinforcedpolymer (CFRP) sheet by epoxy-gelatin.This reinforcement technology made up for the weaknesses oftraditional methods such as the material utilization is low; the prematuredebonding occurs frequently, the original crack width of the structurescannot be lessen. It can improve the structural bearing capacity, enhancestructural stiffness, make the cracks almost close and reduce bendingdeflection. The system of strengthening with pre-stressed CFRP plate consist ofthe tensioning machine and anchorage devices, which should effectuallytension the CFRP to the initial stresses, and sufficiently tied at the anchorend. The mechanical performance of system depends on the value ofpre-stress loss, which would influence on the strengthened structure. Andthe creep behavior of CFRP plate under long term load may have adverseinfluence on the strengthened structure.As the technology of strengthened with CFRP gradually get ripe andpopularized, the demand for CFRP is increased year by year. There is alarge number of homemade CFRP on the market, the material property ofwhich is close bond to the performance on the strengthened structure.Because the imported CFRP is widely used in the experiments, thehomemade CFRP need be test by practice.A set of independently developed the tensioning and anchoring devicewas introduced in this paper. And the material properties of domesticCFRP plate was tested, the pre-stress loss of this reinforcement systemwas researched and analyzed, the creep behavior of CFRP plate under long term load had been monitored by FBG(Fiber Bragg Grating).Theexperimental results shown that the system of strengthening withpre-stressed CFRP plate had a good mechanical performance. Thecalculation method of flexural capacity of the beam strengthened withP-CFRP was proposed in this paper. Based on the calculation method,software designed by Visual Basic which would easy to use for thedesigners. And alkali activated slag cement developed was used to takethe place of chemical anchor bolt that used to fix the anchorage device tothe structural surfaces, which realize the goal of Green Structure.