Evaluation on the cracking resistance of semi-flexible pavement mixture by laboratory research and field validation

Semi flexible pavement (SFP) has drawn great attention in recent years due to its high load bearing capacity. Its strength, rutting resistance, and component constitution have been investigated comprehensively in studies. However, understanding on its cracking performance and mechanism is limited. To this end, this paper evaluates the cracking performance of SFP mixture by utilizing the semi-circular bending (SCB) test. Both SCB monotonic and fatigue tests are employed to characterize the cracking resistance of SFP mixtures with three kinds of asphalt binders, which include SBS (Styrene-Butadiene-Styrene) modified asphalt binder, MA (Modified Agent-100, developed by Sobute New Materials Co. Ltd) modified asphalt binder, and fiber incorporated MA modified asphalt binder. A field inspection was conducted to verify the connections between laboratory results and field performance. SCB results show that the addition of MA-100 and fiber (corresponding to higher optimal asphalt content) lowers the strength of SFP mixtures but increases the fracture energy and flexiblity index at intermediate temperatures. The fatigue test result demonstrates that SFP mixture with MA modified asphalt binder and fibers exhibits the best fatigue performance in the high stress ratio area. According to the field inspection results, pavements using MA modified asphalt binder and fibers have fewer cracks. It is found that there is a good relationship between SCB results obtained at 25 degrees C (fracture energy and flexibility index) and field crack counts. (C) 2019 Elsevier Ltd. All rights reserved.