The experimental study of using composite polymer fiber in concrete

Using the cylinder to take 2L as sample from five equidistant azimuthally and the center point to weight. Wash away the cement slurry in sample thoroughly first. Put the rest into the container full with water and churn. Then, collect the suspended fiber using the square-hole sieve of 75 um aperture. Churn it as more as possible to make sure of collecting whole fiber in samples. Wash clear and dry under 105±5 Celsius degree to constant weight. After cooling to room temperature then weight them respectively and accurate to 0.01g. The dispersion performance will be qualified if the dispersion relative error between arithmetic average value of synthetic fiber content and theoretical calculated value is from -10% to 10%. The concrete test steps is as per "Cement Concrete and Mortar Synthetic Fiber GBT21120-2007". Slump, slump flow of all the fresh concrete were tested to determine the fresh properties of fiber reinforced concrete. The mixing proportions are listed in Table 1, All the strength tests were carried out following the Chinese standard GB/T 50081-2002. Resistance to chloride ion penetration was measured according to ASTM C1202 (Rapid determination of the Chloride Permeability of Concrete) at the curing age of 7d, 28 days using a proportion of the Φ100mm × 50mm cylinders. The early crack resistance test is according to the fiber reinforced concrete testing standards CECS 13-2009. It can be concluded that the working performance of composite fiber concrete are better compared with the single mixed concrete. It is obvious that the spread degree is being larger as the increasing of cellulosic fiber based on the certain adulterate amount. Fiber incorporation has little influence on concrete 7 d, 28 d age compression strength. The 7d and 28d splitting tensile strength, flexural strength were enhanced by incorporation of fibers. The addition of fiber improved the resistance ability of 7d and 28d fiber concrete chloride penetration to a great extent. It improved the ability of corruption resistance from seawater and extended the life of concrete and hence promoting the wide spread usage in marine project. Fiber incorporation delayed the occurrence of early crack and controlled the development of cracks, which made the concrete plastic shrinkage crack width and the maximum crack areas reduced. © (2013) Trans Tech Publications, Switzerland.