聚丙烯纤维改性超细水泥复合注浆材料性能研究

Study on properties of polypropylene fiber-modified ultrafine cement composite grouting materials

为获得高性能矿用水泥基注浆材料,拓展短切纤维在全长锚固领域的应用,以超细硅酸盐水泥为胶凝材料,速凝剂、膨胀剂、聚羧酸减水剂作外加剂,基于单因素试验,探究聚丙烯纤维(PPF)掺量对水泥注浆材料的力学性能、可注性、泌水性、凝结时间、体积收缩性及微观结构的影响规律,并筛选PP改性超细水泥浆液作锚固剂,研究相似实验拉拔条件下全长锚固系统的力学承载性能与声发射特征。结果表明:PPF掺量对超细水泥注浆材料的浆液特性与力学性能具有显著影响,可明显改善超细水泥注浆材料的抗压性能,缩短终凝时间,减小流动度,尤其抗折强度与PPF掺量呈正相关关系。当PPF掺量0.1%时,复合注浆材料S1的综合性能最佳,硬化结石体3 d和28 d抗压强度为60.1 MPa和83.7 MPa,比未添加PPF的参照组S0提高23.4%和23.2%;XRD、SEM及FTIR微观表征证实,适宜PPF不仅能促进水化反应,而且可改善结石体内部裂隙,发挥桥连作用并传递应力,延缓裂纹扩展;拉拔试验表明,基于该复合注浆材料的全长锚固体系力学性能、残余承载能力和最大变形量显著增强,最高拉拔强度是参照组S0的1.356倍,推迟了声发射事件的发生,提升巷道围岩稳定性,为类似全长锚固提供借鉴。

In order to obtain high performance cement-based grouting materials for mining and expand the application of staple fiber in the field of full-length anchorage,Utilizing ultrafine silica cement as the binder material,with the addition of accelerator,expansion agent,and polycarboxylate superplasticizer as additives,a single-factor experiment was conducted to investigate the influence of polypropylene fibers(PPF)content on the mechanical properties,pumpability,bleeding,setting time,volume shrinkage,and microstructure of cement-based grouting materials.For ultrafine cement-based slurries modified with PPF selected as anchor materials,the mechanical load bearing properties and acoustic emission characteristics of the full-length anchoring system were studied under similar pull-out condition.The results revealed that PPF content significantly impacted the slurry characteristics and mechanical property of ultrafine cement grouting materials.It notably enhanced the compressive performance and material toughness while shortening the initial setting time and reducing fluidity.Particularly,there was a positive correlation between flexural strength and PPF content.When the PPF content was 0.1%,the comprehens-ive performance of composite grouting material S1 was optimal.The compressive strength of the hardened specimens at 3 d and 28 d was 60.1 MPa and 83.7 MPa,respectively,which is 23.4%and 23.2%higher than the reference group S0 without PPF.Microscopic character-izations including XRD,SEM,and FTIR confirmed that the suitable PPF not only facilitated hydration reaction but also improved internal cracks within the hardened body.It acted as a bridge,transferred stress,and delayed crack propagation.Pull-out tests indicated that the mechanical property,residual bearing capacity,and maximum deformation of the full-length anchoring system based on this composite grouting material were significantly enhanced.The maximum pull-out strength was 1.356 times the reference group S0,and the occur-rence of acoustic emission events was delayed.It improved the stability of roadway surrounding rocks,providing valuable insights for the similar full-length anchoring applications.