The occurrence of cracks is one of the threatening factors in the durability of concrete structures. The penetration of environmental destructive factors inside the concrete cracks causes steel corrosion and concrete damages and eventually the early deterioration of concrete members. The importance of durability of concrete structures is such that in designing structures, after the control of resistance and ductility, the crack width control is considered as one of the main parameters. Several relations have been proposed by various researchers to predict the width of the crack, and even included in the regulations on concrete structures. Referring to these relationships, it is shown that the effective parameters in the crack width opening are very limited and the use of these relationships is different for calculating crack widths than is usually the case in practice. In the present study, the effects of limestone powder, metal fibers, polypropylene fibers, as well as the effect of concrete strength resistance on the cracking pattern and crack properties in concrete beams were investigated. For this purpose, 12 concrete beams with same dimensions and reinforcement and different mixed designs have been used. Four-point bending beams have been loaded to 60% of the tensile strength of rebars (tensile components), then the profile of cracking in the beams have been compared. The results show that pozzolanic and filler materials or fibers in the concrete structures can be greatly effective in terms of the depth of crack movement through the section height, hardness, height and width of the middle and maximum crack in concrete beams. Key words : Crack width, Metal fibers, Polypropylene fibers, Hybrid fibers, Limestone powder, Compressive strength