Evaluation of Fiber Reinforced Concrete Containing Recycled Concrete Aggregates with Non-Destructive Methods

The use of concrete in the construction industry is growing day by day. Due to the limited life span of concrete structures and also the destruction of concrete structures by natural factors such as earthquakes, floods, hurricanes and ... we will always faced with massive amounts of waste concrete that will cause environmental damages. On the other hand natural resources are also limited for generating aggregates that in near future we should use waste concretes as recycled concrete aggregates for an alternative of natural aggregates to save the natural resources. In this study, the replacement proportion of fine and coarse recycled concrete aggregates with conventional aggregates, is the similar percentages of 0, 25, 50, 75 and 100%, which will include 5 mixing design. With increased use of recycled concrete aggregate, reduction of recycled concrete properties, a increase in water absorption and decrease in slump concrete can be observed that it has been tried to compensate this loss in the slump by using super plasticizer. In order to improve the engineering properties of recycled concrete and Study the Effect of polypropylene fibers on the properties of recycled concrete, the polypropylene fibers with the length of 6 mm and different volume percentages of 0.1, 0.2 and 0.3 percent were used that formed of 15 mixing design. In this study, the Compressive strength, Drying shrinkage, Water absorption, Ultrasonic pulse velocity, Electrical strength and SEM tests were done on the samples. withIncrease in the mass percentage ofpolypropylene fibersin recycledconcretes, decrease in results ofUltrasonic pula velocity and Water absorption, increase in Electrical strength results and alsonegativeeffectsonthe compressive strength have been observed. Interms of0.1 % by volume of polypropylenefibersinconcretedesign, Drying shrinkage improvedbutwith using 0.2and0.3 % by volume ofpolypropylenefibers, the Drying shrinkage increasedComparedwithsampleswithnofibers.