植物纤维喷射混凝土力学及微观性能分析

为研究不同掺量的植物纤维(plant fiber,PF)对植物纤维喷射混凝土(plant fiber shotcrete,PFSC)基本力学性能及导热系数的影响规律,借助扫描电镜(scanning electron microscope,SEM)试验对PFSC的微观结构进行分析。结果表明:相较于素喷射混凝土,掺量为2.0 kg/m³的PFSC抗压强度和劈裂抗拉强度分别提高了17.35%和20.26%,导热系数降低了20.61%。SEM分析表明,低掺量PF在喷射混凝土内部具有较好的分散性,与混凝土基体界面粘结性较好,但PF掺量过高时会出现纤维结团现象,使得PFSC内部缺陷增加。综合力学性能试验结果,建议混凝土PF掺量不宜>2.0 kg/m³。研究成果对于植物纤维喷射混凝土的推广应用有一定参考价值。

Mechanical Properties and Micro-properties of Plant Fiber Shotcrete

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.