Investigation of Different Types of Fibers for Roads by CBR Tests

Abstract

In this study, California Bearing Ratio (CBR) tests in a laboratory were performed to observe the behaviour of granular layer fills reinforced with discrete fibers. Six different fiber types were used in granular road layer by using different methods. Firstly, fibers were added in the road as a layer, then they mixed with soil particles, and as a third method they mixed with soil by laying a geotextile in the road layer, in other words it was used as combine reinforced model. And as the last method only a geotextile was laid and used in the pavement soil. By using these methods, the influence of different type of reinforcements on CBR and bearing capacity ratio values were investigated. Additionally, effects on the pavement layer thickness were calculated and for the best configuration of fiber reinforced sample a cost analysis was conducted. As a result of the study, CBR test values for each fiber type used in the study have different values, and for small penetration levels some test results show no improvement for bearing capacity ratio of the road. It was noticed that when increasing the penetration level, the bearing capacity ratios have larger values. Thus, cost and layer thickness numbers were various for different reinforced road layer models. Therefore, in the real life road projects before using fiber types, cost and performance analysis should be made to determine the more effective one.