The Experimental Study On The Columns Reinforced By Green High-performance Fiber-reinforced Cementitious Composites

Concrete is the most widely used, the biggest dosage building materials in the construction industry, but there are obvious shortcomings:low tensile strength, large brittleness, these shortcomings can easily lead to problems such as insufficient energy dissipation in structures, how to improve the performance of concrete are very concerned at home and abroad. Using fiber reinforced concrete has become one of the hot spots in this field. Among them, the most ground-breaking is the Engineered Cementitious Composite (ECC) which with random distribution of short fibers. ECC has the significant nonlinear deformation, good toughness and high energy absorption ability. It can be used to improve the durability and seismic performance of the structure, and structure safety reserves can be increased.In this paper, Polyvinyl Alcoho Fiber (PVA)and fly ash are used to made a new type of green high-performance materials-Green High-performance Fiber-reinforced Cementitious Composites(GHPFRCC). In GHPFRCC, some Part of cement is replaced by fly ash. This paper mainly contains two parts:GHPFRCC mechanics performance and seismic performance of columns which reinforced by GHPFRCC.First part is mainly through the cube compressive strength test, uniaxial tensile test and bending test to obtain GHPFRCC mechanical behavior law which influenced by water cement ratio, sand ratio, dosage of PVA fiber, fly ash replacement ratio, dosage of water. Establish the regression equations and put forward preparation technology of GHPFRCC Choose a GHPFRCC optimal mixture ratio for reinforced the concrete columns. Results show that the above factors on the GHPFRCC compressive, tensile and bending strength is the biggest impact of the water/cement ratio, and water/cement ratio is smaller, GHPFRCC intensity is higher. PVA fiber content is between1.7%to2%when the mechanics indexes are more outstanding. From60%to65%dosage of fly ash and water reducing agent at1%to1% when GHPFRCC test results are good. Poisson’s ratio in the mixture ratio of the fluctuation is not big, suggested values of0.235, this is slightly higher than the ordinary concrete.The second part of the thesis focuses on quasi-static test of columns which reinforced by GHPFRCC firstly. The finite element software ABAQUS is used to do numerical simulation. Based on the theoretical calculation about ultimate load and displacement t of ABAQUS, quasi-static test scheme is carried out. Damage mode, hysteresis curve and skeleton curves, seismic performance of reinforced concrete columns and so on are studied in the quasi-static test mechanics tests. The preparation technology of GHPFRCC and the interface processing technology are put forward. The test results show that after reinforced by GHPFRCC, the column’s load-carrying capacity is31%times than the same size of concrete column. At the middle of the Column, the displacement increases2.467times,1.481times against concrete column when we push or pull it. At the top of the Column, the number is about2,466times,1.735times. When the GHPFRCC Column damaged, the maximum crack width is not more than0.1mm and the pillar deformation is greatly improved.