为研究纳米MgO对滨海水泥土的改性效果,对纳米MgO改性水泥土(简称NmCS)进行了力学试验和微观测试。通过室内直接剪切试验,研究了纳米MgO的掺入比对水泥土力学特性的影响规律;利用扫描电镜的微观测试方法,观察不同纳米MgO掺入比的NmCS试样的微观结构,分析了纳米MgO改善水泥土强度的机理。结果表明:①纳米MgO改性水泥土强度存在最优掺入比,本次试验对应最优掺入比为10‰;②未掺入纳米MgO的滨海水泥土以小颗粒-松散结构为主,纳米MgO掺入比为10‰的NmCS微观结构最为致密,宏观表现为力学强度的提高。研究结果对现场使用纳米MgO改性水泥土的最优掺量提供试验参考。
Abstract
To investigate the effect of nano-MgO on cement-treated seashore soil, mechanical test and microscopic test were conducted on nano-MgO modified cement-treated seashore soil (NmCS). The mechanical performances of NmCS samples with varied cement content and nano-MgO content were examined via indoor direct shear test. Furthermore, the micro-structural characteristics and mechanism were studied by using SEM technology. Test result unveiled that: (1) there exists an optimum content of nano-MgO for NmCS. Specifically in the test of the present research, the optimum content of nano-MgO is 10‰. (2) Cement-treated seashore soil in the absence of nano-MgO is dominated by loose-structure and small particles; while NmCS with 10‰ nano-MgO is the most compact, reflected as in the improvement of mechanical strength.
关键词
滨海水泥土 /
纳米MgO /
抗剪强度 /
扫描电镜 /
微观结构 /
掺入比
Key words
coastal cement soil /
nano-MgO /
shear strength /
SEM /
micro-structure /
mix ratio
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] LIU Y,LEE F H, QUEK S T,et al. Effect of Spatial Variation of Strength and Modulus on the Lateral Compression Response of Cement-Admixed Clay Slab.Géotechnique,2015,65(10):851-865.
[2] 李 响, 李正平, 胡 贤, 等. 水泥-凝灰岩-粉煤灰复合胶凝材料硬化浆体微观结构特征.长江科学院院报, 2018, 35(5): 115-119.
[3] XIAO Hua-wen, WANG Wei, SIANG H G. Effectiveness Study for Fly Ash Cement Improved Marine Clay. Construction & Building Materials, 2017, 157: 1053-1064.
[4] PAN Yu-tao, LIU Yong, HU Jun, et al. Probabilistic Investigations on the Watertightness of Jet-Grouted Ground Considering Geometric Imperfections in Diameter and Position. Canadian Geotechnical Journal, 2017,54(10):1447-1459.
[5] HOU P K, CHENG X, QIAN J S. Characteristics of Surface-Treatment of Nano-SiO2 on the Transport Properties of Hardened Cement Pastes with Different Water-to-Cement Ratios . Cement & Concrete Composites, 2015, 55: 26-33.
[6] KONG D Y, DU X F, WEI S,et al. Influence of Nano-Silica Agglomeration on Microstructure and Properties of the Hardened Cement-Based Materials. Construction and Building Materials, 2012, 37: 707-715.
[7] NAZARI A, RIAHI S. Effects of Al2O3 Nanoparticles on Properties of Self Compacting Concrete with Ground Granulated Blast Furnace Slag (GGBFS) as Binder . Science China & Technological Sciences, 2011, 54(9): 2327-2338.
[8] KONG D Y, DU X F, WEI S, et al. Influence of Nano-Silica Agglomeration on Microstructure and Properties of the Hardened Cement-Based Materials . Construction and Building Materials, 2012, 37: 707-715.
[9] BAHMANI S H, HUAT B B K, ASADI A, et al. Stabilization of Residual Soil Using SiO2 Nanoparticles and Cement . Construction and Building Materials, 2014, 64: 350-359.
[10] CUI Hong-zhi, JIN, Zhi-yang, BAO Xiao-hua, et al. Effect of Carbon Fiber and Nanosilica on Shear Properties of Silty Soil and the Mechanisms . Construction and Building Materials, 2018, 189: 286-295.
[11] BO Y L, JAYAPALAN A R, KURTIS K E. Effects of Nano-TiO2 on Properties of Cement-Based Materials . Magazine of Concrete Research, 2013, 65(21):1293-1302.
[12] GAO L, REN Z, YU X J. Experimental Study of Nanometer Magnesium Oxide-Modified Clay . Soil Mechanics and Foundation Engineering, 2015, 52(4): 218-224.
[13] 王 伟,张 帅,张 芳,等. 纳米氧化镁改性水泥土一维固结压缩试验研究. 水利学报,2015, 46(增1): 84-89.
[14] LEE S, CHANG I, CHUNG M K,et al. Geotechnical Shear Behavior of Xanthan Gum Biopolymer Treated Sand from Direct Shear Testing . Geomechanics & Engineering, 2017, 12(5): 831-847.
[15] SANI J E, DAYO O A, GODWIN L Y, et al. Reliability Estimate of Unconfined Compressive Strength of Black Cotton Soil Stabilized with Cement and Quarry Dust . Leonardo Electronic Journal of Practices and Technologies, 2017, 16(30): 191-208.
[16] MOUSAVI S E. Stabilization of Compacted Clay with Cement and/or Lime Containing Peat Ash. Road Materials & Pavement Design, 2017,18(6):1304-1321.
[17] MOLA-ABASI H,KORDTABAR B,KORDNAEIJ A.Effect of Natural Zeolite and Cement Additive on the Strength of Sand. Geotechnical & Geological Engineering, 2016, 34(5):1-13.
基金
国家自然科学基金项目(41772311);浙江省自然科学基金项目(LY17E080016);浙江省建设科研项目(2017K179,2016K130)
PDF(2307 KB)
