摘要
探讨纳米纤维素加固土遗址的可行性,将羧基改性的纳米晶纤维素(CNC)和纳米纤丝化纤维素(NFC)分别以滴渗或拌和的方式加固遗址土试样,通过不同龄期下的无侧限抗压强度试验、声波测速、水滴入渗试验和崩解试验,评估了加固试样的力学性质、固化龄期、斥水性和耐水性能.结果表明:2种材料均能在较小的掺量下适度的提高遗址土的力学强度, NFC在拌合加固中效果明显,CNC更适用于滴渗加固.声波测速试验反映了各加固试样的强度增长规律,与无侧限抗压强度较吻合.经CNC滴渗的试样斥水性有所提高,崩解速率较未加固试样降低近50%.扫描电子显微镜图像揭示了纳米纤维素与土颗粒间的胶结形态, NFC拌和样与CNC滴渗样孔隙间表现为明显的非晶相的凝絮状胶结,孔隙度大大减小, CNC拌和样胶结物凝聚现象不显著.
In order to explore the feasibility of reinforcing earthen sites with nanocellulose, the study respectively used carboxyl modified nanocrystalline cellulose(CNC) and nanofibrillated cellulose(NFC)to reinforce the samples by means of mixing or dropping. By conducting unconfined compression tests in different ages, wave velocity tests, water penetration tests and disintegration tests, the research evaluated specimens' mechanical properties, reinforcement age, water repellency and water resistance. The results showed that both the two materials could moderately increase the mechanical strength of the soil even under a low solid content, and the effect of NFC in mixing reinforcement appeared more obvious than that of CNC, while CNC was more suitable for dropping reinforcement. Wave velocity tests could reflect how the strength of each reinforced specimen grew and verify the results of the unconfined compression strength. The water repellency of CNC dropping samples was improved, and the disintegration rate reduced nearly 50% compared with non-reinforced samples. Scanning electron microscope images illustrated the cementation morphology of nanocellulose in soil particles; the NFC mixing and CNC surfacedropping samples exhibited obvious loccular cements of the amorphous phase, which largely reducedthe porosity of soils, while this phenomenon was not significant in CNC mixing samples.
引文
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