Comparative mechanical performances of cement-treated sand reinforced with fiber for road and pavement applications

Cement-treated sand reinforced with fiber (CTSF) has been extensively utilized as the base and subbase layers in road and pavement applications to enhance the mechanical properties of cement-treated sand (CTS). This paper aims to study the influence of seven distinct types of synthetic fibers on the mechanical performances of CTSF specimens. The 5% cement and 2% fiber were mixed with sand and water to create the CTSF specimens. The different seven fiber types used included (i) 12-mm-long polypropylene, (ii) 19-mm-long polypropylene, (iii) 33-mm-long steel, (iv) 40-mm-long polypropylene, (v) 50-mm-long steel, (vi) 55-mm-long polypropylene, and (vii) 58-mm-long polyolefin fibers. Three mechanical tests were performed on the CTSF specimens: unconfined compressive, splitting tensile, and flexural strength tests. The overall performance of the CTSF for each test was determined by six subperformance parameters: (1) improvement peak strength ratio; (2) brittleness index; (3) improvement deformation ratio; (4) improvement toughness ratio; (5) toughness index; and (6) strength index. The debonded interface between the surface of each fiber and the cemented sand matrix was observed using scanning electron microscopy. Finally, the comparative overall mechanical performance was analyzed based on the subperformance indicators to determine the most suitable fiber type corresponding to each applied loading type. The results illustrated that the most suitable fiber types for CTSF subjected to unconfined compressive, splitting tensile, and flexural stresses were 58-mm-long polyolefin fiber, 50-mm-long steel fiber, and 55-mm-long polypropylene fiber. The current study proved that synthetic fiber types significantly affect the mechanical performance of CTSF used for road and pavement applications. Thus, the overall performance concept presented in the current study is useful for selecting the most suitable fiber type corresponding to different failure mechanisms, which is of practical significance in pavement performance and design.