Comparison of the Effect of Micro and Macro Synthetic Fibers on the Strength Properties of Jointed Concrete Pavements Considering the Residual Flexural Strength

The addition of fibers with different physical and strength properties has different effects on the strength properties of jointed concrete pavements at rupture and also on the residual flexural strength of the pavement. This study investigates the separate and comparative effect of micro and macro synthetic fibers on the strength properties of jointed concrete pavements, considering the residual flexural strength of the pavement. For this purpose, the effect of adding two types of macro fibers and one type of micro fiber in the content of 1, 2, and 3 kg/m3 on compressive strength, splitting tensile strength, flexural strength, and flexural performance after cracking of concrete pavement were investigated. The results showed that micro fibers in all consumption contents have the least effect on the strength properties of pavement compared to macro fibers. Also, the addition of macro fibers did not have a significant effect on the compressive strength, but the splitting tensile strength, flexural strength, and residual flexural strength of pavement were significantly increased. The effect of macro fibers on improving the splitting tensile strength and modulus of rupture of pavement occurred at dosage rates higher than 2 kg/m3. However, the most significant increase in the equivalent flexural strength ratio of fiber reinforced concrete pavement occurred in the range of 1 to 2 kg/m3, and by adding higher contents of macro fibers, the increasing growth trend of residual flexural strength decreased. It was founded that macro fibers have the most excellent effect on flexural strength and residual flexural strength of the pavement. Also, the performance of twisted and continuously embossed macro fibers in all dosage rates was approximately the same.