Carbon Fiber Smart Material Applied In Performance Test Of Creep And Shrinkage In Concrete Bridge

With the support of NSFC (National Natural Science Foundation of China) Funding: smart concrete and its structure(program No:50238040), through reading many references, I get to know that the prestressed concrete, especially the shrinking, creep in long-span bridge. Its influence to long-span Bridge is still a difficult problem to engineers.Considering the 50M rail of prestressed concrete box girder in ChongQing Chao tianmen Changjiang Bridge, this paper adopted a new fashioned sensor which was based on the carbon fiber resin group composite to test the concrete structure's shrinking, creep. Besides, we review the adaptability of carbon fiber smart concrete as the inspecting sensor through comparing examining results with theoretical results.This paper includes the following contents:1. Through the research on concrete's shrinking-creep, we obtained the computation method to the analysis on prestressed concrete box girder in which the change of modulus in concrete along with time, the expression of creep compliance,ratio of reinforcement,relaxation of prestressed reinforcement,concrete shrinkage will be considered. And its detailed analysis process and final calculation flow are given.2. We developed the carbon fiber resin group strain sensor. Through the static performance in experiments, we found that this sensor's sensitivity can be 77, the. sensing limit can be 2500με, linear degree can be 95%, null-drift to resistance itself is less than 1%. The sensor has sound static performance in the testing device when in the proceed of concrete creep.3. The results show that the value of early shrinking-creep has the average error -12 %, max error -39% compared to its theoretical value. Thus the sensor is generally satisfying. The testing result of creep has the same trend with theoretical analysis, but has relatively bigger difference in tension of prestressing tendon.4. The analysis of shrinking-creep in this paper will be easily amended to analyze and calculate the concrete's shrinking-creep to other kinds of structure.