[1] Zhang Dingwen, Liu Ziming, Sun Xun, Cao Zhiguo, et al. Laboratory tests on enhancing strength of cement stabilized organicsoil with addition of phosphor gypsum and calcium aluminate cement [J]. Journal of Southeast University (English Edition), 2017, 33 (3): 301-308. [doi:10.3969/j.issn.1003-7985.2017.03.008]

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Laboratory tests on enhancing strength of cement stabilized organicsoil with addition of phosphor gypsum and calcium aluminate cement()

磷石膏-高铝水泥双掺增强水泥固化有机质土强度室内试验研究

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Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]

Volumn:

33

Issue:

2017 3

Page:

301-308

Research Field:

Civil Engineering

Publishing date:

2017-09-30

Info

Title:

Laboratory tests on enhancing strength of cement stabilized organicsoil with addition of phosphor gypsum and calcium aluminate cement

磷石膏-高铝水泥双掺增强水泥固化有机质土强度室内试验研究

Author(s):

Zhang Dingwen¹;  Liu Ziming¹;  Sun Xun²;  Cao Zhiguo¹

¹School of Transportation, Southeast University, Nanjing 210096, China
²Sihong County Transportation Board, Sihong 223900, China

章定文¹;  刘子铭¹;  孙迅²;  曹智国¹

¹东南大学交通学院, 南京 210096; ²泗洪县交通运输局, 泗洪 223900

Keywords:

organic soil;  stabilization;  strength;  ettringite

有机质土;  固化;  强度;  钙矾石

PACS:

TU411

DOI:

10.3969/j.issn.1003-7985.2017.03.008

Abstract:

In order to improve the engineering properties of organic soil, a new stabilization agent is developed by the addition of phosphor gypsum and calcium aluminate cement. The artificial organic soil is applied in the study and a series of laboratory tests were carried out to explore new stabilization agents and determine the optimal dosage. Unconfined compressive strength(UCS)and the pH value of soil pore solution were measured. The influence of organic content, agent composition and curing time on the UCS of samples were also researched. The test results show that the UCS of stabilized organic soils by a new agent achieves approximately 800 and 1 200 kPa at 28 and 90 d curing time, respectively. The pH test results show that a high alkaline environment is a necessary and not a sufficient condition for high strength. The strength of stabilized soil is related to the hydration product of stabilization agent. The mechanism of strength formation was also explored by X-ray diffraction(XRD), mercury intrusion porosimetry(MIP)and scanning electron microscope(SEM)tests. A large amount of ettringite is produced to fill the large pores of organic soils, which contribute to the high UCS value of stabilized organic soils. The new agent can solidify the organic soil successfully as well as provide a new approach to treat the organic soil.

为了改善有机质土的工程特性, 通过向水泥中外掺磷石膏与高铝水泥的方法, 研发了一种新型的有机质土固化剂.通过室内试验研究了新型固化剂对人工配制有机质土强度的增强效果, 并比选固化剂的最优配方.对不同配方固化剂固化有机质土开展了无侧向抗压强度试验和固化土孔隙液pH值测试.试验结果表明, 外掺磷石膏与高铝水泥后固化有机质土的无侧限抗压强度可达800~1 200 kPa.pH值测试结果表明, 高碱性环境是得到高强度的必要而非充分条件, 其与构成强度的主要矿物密切相关.XRD, SEM和MIP试验结果证实新矿物钙矾石的生成与孔隙填充有利于提高固化有机质土体强度.该研究成果可为有机质软土的固化提供一种新的解决方法.

References:

[1] Hobbs N B. Mire morphology and the properties and behaviour of some British and foreign peats[J]. Quarterly Journal of Engineering Geology and Hydrogeology, 1986, 19(1): 7-80. DOI:10.1144/gsl.qjeg.1986.019.01.02.
[2] Timoney M J, McCabe B A, Bell A L. Experiences of dry soil mixing in highly organic soils[J]. Proceedings of the Institution of Civil Engineers—Ground Improvement, 2012, 165(1): 3-14. DOI:10.1680/grim.2012.165.1.3.
[3] Kujala K, Mäkikyrö M, Lehto O. Effect of humus on the binding reaction in stabilized soils[C]//Grounting and Deep Mixing. Balkema, Rotterdam, 1996: 415-420.
[4] Tastan E O, Edil T B, Benson C H, et al. Stabilization of organic soils with fly ash[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2011, 137(9): 819-833. DOI:10.1061/(asce)gt.1943-5606.0000502.
[5] Hayashi H, Nishimoto S. Strength characteristic of stabilized peat using different types of binders[C/OL]//Proceedings of the International Conference of Deep Mixing Best Practices and Recent Advances, Deep Mixing. 2005. http://thesis.ceri.go.jp/center/doc/thesis/jiban/0013772000.pdf.
[6] Kolay P K, Rahman M A. Physico-geotechnical properties of peat and its stabilisation[J]. Proceedings of the Institution of Civil Engineers-Ground Improvement, 2016, 169(3): 206-216. DOI:10.1680/jgrim.15.00025.
[7] American Society for Testing and Materials. ASTM D.2487 Standard practice for classification of soils for engineering purposes(unified soil classification system)[S]. West Conshohocken, PA, USA: ASTM International, 2006.
[8] American Society for Testing and Materials. ASTM D4318-17 Standard test methods for liquid limit, plastic limit, and plasticity index of soils[S]. West Conshohocken, PA, USA: ASTM International, 2000.
[9] American Society for Testing and Materials. ASTM D. 2166 Standard test method for unconfined compressive strength of cohesive soil[S]. West Conshohocken, PA, USA: ASTM International, 2016.
[10] American Society for Testing and Materials. ASTM D. 4972-01 Standard test method for pH of soils[S]. West Conshohocken, PA, USA: ASTM International, 2001.
[11] Axelsson K, Johansson S E, Andersson R. Stabilization of organic soils by cement and puzzolanic reactions—feasibility study[R]. Linkoping, Sweden: Swedish Deep Stabilization Research Center, 2002.
[12] Clare K E, Sherwood P T. The effect of organic matter on the setting of soil-cement mixtures[J]. Journal of Applied Chemistry, 1954, 4(11): 625-630.
[13] Young J F. A review of the mechanisms of set-retardation in Portland cement pastes containing organic admixtures[J]. Cement and Concrete Research, 1972, 2(4): 415-433.
[14] Odler I, Colán-Subauste J. Investigations on cement expansion associated with ettringite formation[J]. Cement and Concrete Research, 1999, 29(5): 731-735. DOI:10.1016/s0008-8846(99)00048-4.
[15] Martínez-Ramírez S, Gutierrez-Contreras R, Husillos-Rodriguez N, et al. In-situ reaction of the very early hydration of C3 A-gypsum-sucrose system by Micro-Raman spectroscopy[J]. Cement and Concrete Composites, 2016, 73: 251-256. DOI:10.1016/j.cemconcomp.2016.07.020.
[16] Che D R, Luo C Y, Shen S L. Relationship between pH value and electrical conductivity and strength characteristics of cement treated Shanghai clayey soil[J]. Rock & Soil Mechanics, 2012, 33(12):3611-3615.
[17] Babushkin V I, Matveev G M, Mchedlov-Petrosian O P. Thermodynamics of silicates[M]. Springer, 1985:75-82.
[18] Tremblay H, Duchesne J, Locat J, et al. Influence of the nature of organic compounds on fine soil stabilization with cement[J]. Canadian Geotechnical Journal, 2002, 39(3): 535-546. DOI:10.1139/t02-002.
[19] Huang X, Xu S, Ning J G. Experimental research on stabilized soft soils by alumina bearing modifier[J]. Chinese Journal of Rock Mechanics and Engineering, 2007, 26(1): 156-161.

Memo

Memo:

Biography: Zhang Dingwen(1978—), male, doctor, professor, zhangdw@seu.edu.cn.
Foundation items: The National Natural Science Foundation of China(No. 51578148), the Project of China Communications Construction(No.2015-ZJKJ-26), the Fundamental Research Funds for the Central Universities, the Scientific Innovation Research of College Graduates in Jiangsu Province(No.SJLX15_0062).
Citation: Zhang Dingwen, Liu Ziming, Sun Xun, et al.Laboratory tests on enhancing strength of cement stabilized organic soil with addition of phosphor gypsum and calcium aluminate cement[J].Journal of Southeast University(English Edition), 2017, 33(3):301-308.DOI:10.3969/j.issn.1003-7985.2017.03.008.

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