Investigation of the Usability of Waste Kevlars in Concrete Road Pavements

At the present time, fiber optic cables are generally used in the communication sector. In our country, there are 324 thousand km of fiber cables including only 256 thousand km in Turk Telekom operators and 68 thousand km in other operators. These cables, which have a service life of 20 years, need to be renewed over time and the cables that are out of use are scrapped. An average of 15,000 km of cable is scrapped annually. Approximately 5 Kg of kevlars become waste in 1 km length cable. Since waste kevlars do not have a separate usage area, they cannot be recycled to the economy. In this study, the usability of the concrete produced with kevlar on the road superstructure was investigated. For this purpose, water / binder ratio (0.40, 0.45, 0.50), silica fume (%0, 5, 10 instead of cement), kevlar (0 gr / m3, 500 gr / m3, 1000 gr / m3) and polypropylene fiber (0 gr / m3, 500 gr / m3, 1000 gr / m3) are determined as mixture variables. According to the full factorial experiment design, 3 x 34 = 243 samples must be poured for each of the compressive strength, rupture modulus and elasticity modulus tests. In the case of a grand total, 729 samples are required if a full factorial experiment design is applied. For this reason, Taguchi method was used for the experimental design and optimum mixture variables that gave 28 days of flexural and compressive strength were determined by the modulus of elasticity. Considering the factor and number of the levels, the $L_9$ orthogonal array was chosen as the experimental design and the study to be performed with a total of 3x9x3 = 81 samples and 729 samples was represented. From the results of the experiment, it has been observed that Kevlar material has positive effects on the compressive, flexural and elasticity modulus values added up to 500 g / m3 in the concrete. Since polypropylene fiber and kevlar were tested together in the experiments, it is predicted that this rate will increase only in the use of kevlar. From the results, it was observed that Kevlar which is a waste material can be brought to the economy by adding to the concrete.