Performance of Polypropylene Fiber-Reinforced Solidified Soil

Urgent repair and construction of airstrips is a research hotspot in global airport engineering. Selecting the proper structural materials is a key component of the airstrip repair process. First, with unconfined compressive strength and splitting tensile strength, the fiber length and content of polypropylene (PP) fiber-reinforced solidified soil were optimized. Then, using a scanning electron microscope, the reinforcing mechanism of PP fiber on soil and the influence mechanism of fiber parameters on fiber-reinforced soil were discussed and analyzed. Lastly, a full-scale test section was paved, on which static and dynamic loading tests were performed to verify the carrying capacity and deformation characteristics of the full-scale test section. The above research provides a theoretical foundation and data support for the urgent repair and construction of airstrip. Results indicate that PP fiber with length of 12 mm and fiber content of 0.3% has optimal performance and economic cost. The reinforcing mechanism of fiber-reinforced soil can be summarized to be the effect of a one-dimensional lacing wire and the effect of a three-dimensional network structure. Fibers show two failure modes of pull-out and tensile failure. After 20000 dynamic loading cycles, the stress at the bottom of each structural section varies less, the graded plastic deformation is stable, and the cumulative plastic deformations of the fiber-reinforced soil base, solidified soil base, and cemented soil base pavement structures are 0.83 mm, 0.93 mm, and 1.2 mm, respectively. Pavement structure composed of fiber-reinforced solidified soil can meet the load capacity requirements for use in airstrips under the characteristics of time-sensitive application.