Investigation of the effect of fiber size and dosage on concrete performance properties

With the developing technology, the largest grain diameter of the aggregates (Dmax) used in concrete decreases due to the dense reinforcement used in reinforced concrete structural elements and the expectation of higher compressive strength from concrete. With the reduction of aggregate diameters, problems such as excessive shrinkage and water requirement occur in concrete. Micro-sized fibers also prevent capillary gaps and brittle fracture in concrete in the construction industry for many years; They are used to increase tensile strength, durability (permanence), abrasion resistance, toughness of concrete, bending strength. It is thought that the use of fiber will positively affect the concrete performance properties for the problems caused by the reduction of aggregate diameters. In this study, concrete with fixed plasticizer percentage and fixed W/C ratio was produced in the concretes with 350, 400 and 450 kg cement dosage, produced in two separate series with Dmax 4 and 16 mm size. The effects of polypropylene fiber (PP) and glass fiber (CL) on the fresh and hardened concrete performance were investigated on these produced samples, with 3, 6 and 12 mm lengths and 2.2, 4.4 and 6.6 dm3 dosages in 1000 dm3 concrete. As a result of the experiments, it was observed that the fibers used adversely affected the strength and processability. The addition of CL affected more than the addition of PP in general. The amount of decrease in the results was higher with the addition of CL.