聚丙烯纤维加筋增强钢渣混合土性能的研究

A Study of the Performance of Polypropylene Fiber Reinforced Steel Slag Mixed Soil

为进一步改善钢渣混合土的综合性能,在钢渣混合土中掺入韧性良好的聚丙烯纤维,制备纤维加筋钢渣混合土,研究纤维长度、掺量对钢渣混合土无侧限抗压强度、干缩、抗冻等性能的影响,并采用扫描电镜表征分析加筋对受冻试件微观形貌的影响,探讨加筋纤维增强钢渣混合土综合性能的机理。结果表明:纤维加筋能有效改善钢渣混合土的抗压、干缩及抗冻性能,加筋纤维长度12 mm、掺量0.25%时综合性能相对最优,加筋试件延性变好,抗压强度提升达16.74%;失水量有所增大,但干缩系数减小达37.51%;受冻后质量损失率下降、残余强度比提升达6.33%。此时的试件微观形貌相对完整,故表现出更好的抗干缩和抗冻性能,聚丙烯纤维与基体间有效黏结提供的界面摩擦力及其在基体内形成的立体网状结构是钢渣混合土性能增强的重要基础。

To further improve the comprehensive performance of steel slag mixed soil,polypropylene fibers with good toughness were incorporated into the mix to prepare fiber-reinforced steel slag soil.The effects of fiber length and dosage on the unconfined compressive strength,dry shrinkage,freeze-thaw resistance and other properties of the steel slag mixed soil were studied.Scanning electron microscope was used to characterize and analyze the effect of reinforcement on the microstructure of frozen specimen,and the mechanism of fiber reinforcement on the comprehensive performance of steel slag mixed soil was investigate.The results show that fiber reinforcement can effectively improve the compressive,dry shrinkage and frost resistance of steel slag mixed soil.The optimal comprehensive performance is achieved with fiber length of 12 mm and a dosage of 0.25%.The ductility of the reinforced specimen improves,with compressive strength increasing by up to 16.74%.While the water loss increases,the dry shrinkage coefficient decreases by up to 37.51%.After freezing,the mass loss rate decreases,and the residual strength ratio increases by up to 6.33%.At this stage,the microstructure of the specimens is relatively intact,thus exhibiting better dry shrinkage and freeze-thaw resistance.The effective bonding between polypropylene fibers and the matrix provides interfacial friction and formation of a three-dimensional network structure within the matrix is a critical basis for the enhanced performance of the steel slag mixed soil.