纳米纤维素材料加固土遗址初探
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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.
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
[1]王旭东.中国干旱环境中土遗址保护关键技术研究新进展[J].敦煌研究, 2008(6):6-12.
[2]李最雄.丝绸之路古遗址保护[M].北京:科学出版社,2004:118-122.
[3]孙满利,王旭东,李最雄.西北地区土遗址病害[J].兰州大学学报:自然科学版, 2010, 46(6):41-45.
[4]崔凯,陈蒙蒙,谌文武,等.干湿与盐渍耦合作用下土遗址强度劣化机理[J].兰州大学学报:自然科学版, 2017,53(5):582-587.
[5] Oddy W A. Chemistry in the conservation of archaeological materials[J]. Science of the Total Environment, 1994,143(1):121-126.
[6]柴新军,钱七虎,杨泽平,等.点滴化学注浆技术加固土遗址工程实例[J].岩石力学与工程学报, 2009, 28(增刊1):2980-2985.
[7]周双林,原思训,杨宪伟,等.丙烯酸非水分散体等几种土遗址防风化加固剂的效果比较[J].文物保护与考古科学, 2003, 15(2):40-48.
[8] Maravelaki-Kalaitzaki P, Kallithrakas-Kontos N, Agioutantis Z, et al. A comparative study of porous limestones treated with silicon-based strengthening agents[J]. Progress in Organic Coatings, 2006, 57(1):49-60.
[9]陈利君.硅溶胶/硅丙复合土遗址加固剂的合成与应用[D].西安:西安建筑科技大学, 2012.
[10]张秉坚,魏国锋,杨富巍,等.不可移动文物保护材料研究中的问题和发展趋势[J].文物保护与考古科学,2010, 22(4):102-109.
[11]李最雄,赵海英,孙满利.中国丝绸之路土遗址的病害及PS加固[J].岩石力学与工程学报, 2009, 28(5):1047-1054.
[12]孙满利,王旭东,李最雄.交河故城嘹望台保护加固技术[J].岩土力学, 2007, 28(1):163-168.
[13]谌文武,杨光,崔凯,等.土遗址片状剥离加固现场渗透试验[J].兰州大学学报:自然科学版, 2017, 53(3):309-315.
[14]李迎,王丽琴.纳米材料在文物保护中应用的研究进展[J].材料导报, 2011, 22(增刊2):34-37.
[15]芦长椿.纳米纤维素的应用研究及潜在市场分析[J].合成纤维, 2016, 45(5):46-50.
[16]袁晔,范子千,沈青.纳米纤维素研究及应用进展Ⅰ[J].高分子通报, 2010(2):75-79.
[17]唐文睿,缪昌文,丁蓓.微晶纤维素增韧混凝土的性能研究及机理分析[J].新型建筑材料, 2010, 37(7):4-6.
[18]韩国强.土遗址化学加固效果评价试验研究[D].北京:中国地质大学, 2012.
[19]张虎元,赵天宇,王旭东.中国古代土工建造方法[J].敦煌研究, 2008(5):81-90.
[20]中华人民共和国建设部. GB/T 50123-1999,土工试验方法标准[S].北京:中国标准出版社, 1999.
[21] Bisdom E B A, Dekker L W, Schoute J F. Water repellency of sieve fractions from sandy soils and relationships with organic material and soil structure[J]. Geoderma, 1993, 56:105-118.
[2]李最雄.丝绸之路古遗址保护[M].北京:科学出版社,2004:118-122.
[3]孙满利,王旭东,李最雄.西北地区土遗址病害[J].兰州大学学报:自然科学版, 2010, 46(6):41-45.
[4]崔凯,陈蒙蒙,谌文武,等.干湿与盐渍耦合作用下土遗址强度劣化机理[J].兰州大学学报:自然科学版, 2017,53(5):582-587.
[5] Oddy W A. Chemistry in the conservation of archaeological materials[J]. Science of the Total Environment, 1994,143(1):121-126.
[6]柴新军,钱七虎,杨泽平,等.点滴化学注浆技术加固土遗址工程实例[J].岩石力学与工程学报, 2009, 28(增刊1):2980-2985.
[7]周双林,原思训,杨宪伟,等.丙烯酸非水分散体等几种土遗址防风化加固剂的效果比较[J].文物保护与考古科学, 2003, 15(2):40-48.
[8] Maravelaki-Kalaitzaki P, Kallithrakas-Kontos N, Agioutantis Z, et al. A comparative study of porous limestones treated with silicon-based strengthening agents[J]. Progress in Organic Coatings, 2006, 57(1):49-60.
[9]陈利君.硅溶胶/硅丙复合土遗址加固剂的合成与应用[D].西安:西安建筑科技大学, 2012.
[10]张秉坚,魏国锋,杨富巍,等.不可移动文物保护材料研究中的问题和发展趋势[J].文物保护与考古科学,2010, 22(4):102-109.
[11]李最雄,赵海英,孙满利.中国丝绸之路土遗址的病害及PS加固[J].岩石力学与工程学报, 2009, 28(5):1047-1054.
[12]孙满利,王旭东,李最雄.交河故城嘹望台保护加固技术[J].岩土力学, 2007, 28(1):163-168.
[13]谌文武,杨光,崔凯,等.土遗址片状剥离加固现场渗透试验[J].兰州大学学报:自然科学版, 2017, 53(3):309-315.
[14]李迎,王丽琴.纳米材料在文物保护中应用的研究进展[J].材料导报, 2011, 22(增刊2):34-37.
[15]芦长椿.纳米纤维素的应用研究及潜在市场分析[J].合成纤维, 2016, 45(5):46-50.
[16]袁晔,范子千,沈青.纳米纤维素研究及应用进展Ⅰ[J].高分子通报, 2010(2):75-79.
[17]唐文睿,缪昌文,丁蓓.微晶纤维素增韧混凝土的性能研究及机理分析[J].新型建筑材料, 2010, 37(7):4-6.
[18]韩国强.土遗址化学加固效果评价试验研究[D].北京:中国地质大学, 2012.
[19]张虎元,赵天宇,王旭东.中国古代土工建造方法[J].敦煌研究, 2008(5):81-90.
[20]中华人民共和国建设部. GB/T 50123-1999,土工试验方法标准[S].北京:中国标准出版社, 1999.
[21] Bisdom E B A, Dekker L W, Schoute J F. Water repellency of sieve fractions from sandy soils and relationships with organic material and soil structure[J]. Geoderma, 1993, 56:105-118.