Concrete fibers
Before introducing the products of this section, it is necessary to know that the types of fibers that can be used in concrete can be classified in two ways. The first classification is based on the type of fibers, which in this classification standard ASTM-C1116 classifies the types of fibers into four groups based on their type.
First group: steel fibers
Second group: synthetic fibers (it is also called polymer or plastic)
The third group: glass fibers
Fourth group: natural fibers
Of the above, fiber concrete design guidelines such as ACI544 are provided only for the first and second groups.
Another type of fiber classification is based on their physical dimensions, and in this classification, fibers whose diameter is greater than 0.3 mm are called macro and fibers whose diameter is less than 0.3 mm are called micro. Therefore, each of the steel and polymer fibers can be macro or micro.
This point is also important and we should know that the use of micro fibers in concrete only plays the role of crack control and there is no design method for its consumption. However, according to the ACI544 design guidelines, macro fibers are known as a reinforcing agent for concrete, and in addition to being able to be replaced with thermal rebars, it can also lead to a reduction in the consumption of structural rebars. In this regard, the design relationships for bending and shear are fully presented in the ACI544 design guidelines.
