Effect of polypropylene fiber on mechanical properties of cemented sandy soil

This study investigates the effects of polypropylene fibres and cement on the properties of Chlef sandy soil, addressing the challenges posed by weak or unsuitable soils in geotechnical engineering. Fibre reinforcement and cement stabilization are explored as effective, cost-efficient solutions for improving soil strength in applications such as pavement layers and retaining walls. A series of laboratory tests, including compaction, unconfined compressive strength (UCS), and California Bearing Ratio (CBR), were conducted to analyze the effects of adding polypropylene fibres and cement on the soils engineering behavior. The fibre content was varied from 0 to 0.8% by weight, with 5% cement content, and the specimens were cured for 7 and 14 days. The results show that both cement and fibre additions increase the maximum dry unit weight of the soil. The UCS increases with higher fibre content, with a maximum improvement of 170% at 0.8% polypropylene fibre after 14 days of curing. Curing time also positively affects UCS, with more significant improvements observed at higher fibre contents. Furthermore, the combination of cement and polypropylene fibres significantly enhances CBR values. For instance, the unsoaked CBR value increased by 64% with the addition of 5% cement and 0.8% polypropylene fibres. These findings suggest that cement and polypropylene fibre reinforcement can notably improve the engineering properties of sandy soils.