Study On Development And Durability Of The GFRP With EP/OMMT Matrix Modified By Nano-Technology

The degradation of reinforcement concrete structures, due to Reinforcement in carbonation and chlorideion environments corrode gradually, is a key issue and urgent to be solved by every country in the world. The existing research results indicate polymer/organoclay nanocomposites can be employed as high performance coating to enhance the durability of concrete structures, or the matrix of fiber reinforced polymers (FRP) to enhance the durability of FRP-retrofitted structures. In harsh environments (such as acidic, alkaline environment, high temperature moisture, and so on), FRP will also be subjected to degradation even if they normally have higher corrosion resistance than steel reinforcement, especially for the GFRP composite, which is the most potential engineering FRP due to its higher output and lower cost.To expand the applicability of FRP in civil engineering, the present thesis will focus on using nano-modification technology to improved durability performences of the resin matrix, namely the EP/OMMT matrix. Then, a novel GFRP nanocomposite will be developed with the EP/OMMT matrix. It has good mechanical properties and Excellent durabilities facing on the reinforced concrete structures. The main research results are showed as follows:(1) Epoxy/organoclay nanocomposites with small loading of I.30P organoclay (up to 4wt%) were fabricated by the in-situ polymerization method. With XRD and TEM analysis, the fabricated epoxy nanocomposites are found to exhibit intercalated/exfoliated structure. According to characterization FTIR technology, because the nanocomposites have no new chemical bonds, no chemical reaction. And in the DMA analysis, the results showed that with the amount (about 1~3wt%) of clay in polymer, the thermo-mechanical property and thermal stability of epoxy were improved. But while with excessive clay in polymer, the results are backfire.(2) The mechanical properties were studied respectively through the tensile test and the flexural test. The tensile and flexural properties were improved with organoclay increases. But the study also found, while the organoclay content was more than a critical value (here was 2wt%), the each mechanical property of nanocomposite would decrease gradually, even lower than neat epoxy resin, especially in flexural strength. With the organoclay content increased, the tensile and flexural modulus developed in different way. The tensile modulus was stable development after maximizing, but the flexural modulus was a gradual decline after maximizing. The 2wt% Organoclay content was a watershed in this research. . Because there were a few defects occurred in the resin matrix due to the excessive Organoclays were easily agglomerated, which leaded to the stress concentration under loading.(3) In order to carrying out mechanical and artificial simulated accelerated aging tests, the laminations with 60% fiber volume fraction were made from GFRP and Nano-GFRP composite respectively. The testing results showed that the Nano-GFRP composites demonstrated better tensile and bending properties, especially in ductilityIn accelerated aging tests, Nano-GFRP composites showed excellent durability while immersed in purified water, as well as in alkali solution.