Abstract: The microstructure of plant fiber shotcrete (PFSC) is analyzed by means of scanning electron microscopy (SEM) in a purpose of investigating the influence of plant fiber dosage on the mechanical properties and thermal conductivity of PFSC. Compared with those of plain shotcrete, the compressive strength and splitting tensile strength of PFSC dosed with 2.0 kg/m³ plant fiber increase by 17.35% and 20.26%, respectively, while the thermal conductivity reduces by 20.61%. SEM analysis shows that plant fiber in low-volume well disperses in the interior of the shotcrete and adheres to the concrete matrix. However, large content of plant fiber agglomerates in the shotcrete, leading to more internal defects of PFSC. According to the comprehensive mechanical properties test results, we recommend that the plant fiber content should not exceed 2.0 kg/m³.

Key words: shotcrete, plant fiber, mechanical properties, thermal conductivity, microscopic performance