Malaysian Journal of Analytical Sciences Vol 24 No 4 (2020): 578 - 586

 

 

 

 

STABILISATION OF PEAT SOIL USING MAGNESIUM OXIDE: A PRELIMINARY STUDY

 

(Penstabilan Tanah Gambut Menggunakan Magnesium Oksida: Satu Kajian Awal)

 

Lily Suhaila Yacob* and Amelia Md Som

 

Green Chemistry & Sustainable Technology Cluster,

Universiti Kuala Lumpur-Malaysian Institute Chemical & Bioengineering Technology, 78000 Alor Gajah, Malacca, Malaysia

 

*Corresponding author:  lilysuhaila@unikl.edu.my

 

 

Received: 20 November 2019; Accepted: 30 June 2020; Published: 11 August 2020

 

 

Abstract

This is a preliminary study for the stabilisation of peat soil from Teluk Kerang, Pontian, Johor using ordinary Portland cement (OPC) and magnesium oxide (MgO) as binders. Spent garnet and sand were used as fillers. In Malaysia, peat soil has been identified as one of the major groups of soils with low shear strength and high compressibility. Peatlands are used as an alternative option for future development due to lack of suitable lands and expensive cost. The presence of soft or peaty soil is a major problem in construction. The properties of peat soil used in this study were analysed and it was found to be acidic with the pH value of 4.15. According to von Post classification, peat soil can be classified as H3. In this research, various ratios of mix design for binders (OPC and MgO) and fillers (spent garnet and sand) were studied. Peat soil and binders (70:30) were inserted into a PVC pipe with the diameter of 50 mm and length of 200 mm. Unconfined compressive strength (UCS) test was conducted to determine the strength gained after 28 days of curing period. The relationships between the UCS and binder of the specimen after curing were investigated to determine the effect of binder changes on the strength of stabilised peat. The results showed that the samples without MgO could not maintain their form even when the samples were assisted with fillers. For the OPC:MgO ratio of 50:50, the samples achieved the UCS value of 32.97 kPa. The findings showed the potential contribution of MgO in peat stabilisation, and the addition of OPC alone is insufficient to stabilise the peat. The pH values varied from 9.0 to 10.1. Overall, the UCS test results showed that peat soil stabilisation using MgO and spent garnet improved the strength of stabilised peat

 

Keywords:  peat soil, magnesium oxide, unconfined compressive strength test, pH, moisture content

 

Abstrak

Ini adalah kajian awal untuk penstabilan tanah gambut dari Teluk Kerang, Pontian, Johor dengan menggunakan simen Portland biasa (OPC) dan magnesium oksida (MgO) sebagai pengikat. Garnet dan pasir yang digunakan sebagai pengisi. Di Malaysia, tanah gambut telah dikenalpasti sebagai salah satu daripada kumpulan utama tanah yang mempunyai kekuatan ricih yang rendah dan kebolehmampuan tinggi. Tanah gambut akan menjadi pilihan alternatif untuk pembangunan masa depan disebabkan kekurangan tanah yang sesuai dan harga mahal. Kehadiran tanah lembut atau tanah gambut adalah masalah utama dalam pembinaan. Sifat-sifat tanah gambut yang digunakan dalam kajian ini dianalisis dan didapati berasid dengan nilai pH 4.15. Mengikut klasifikasi von Post, tanah gambut dapat diklasifikasikan di antara H3. Dalam kajian ini, pelbagai nisbah reka bentuk campuran untuk pengikat (OPC dan MgO) dan pengisi (garnet dan pasir) dikaji. Tanah gambut dan pengikat (70:30) diletakkan di dalam PVC paip berukuran 50 mm diameter dan 200 mm panjang. Ujian kekuatan mampatan tak terkurung (UCS) telah dijalankan untuk menentukan kekuatan selepas 28 hari tempoh pengawetan. Hubungan antara UCS dan pengikat spesimen selepas pengawetan disiasat untuk menentukan kesan pengikat pada kekuatan gambut yang stabil. Keputusan menunjukkan bahawa sampel tanpa MgO tidak dapat mengekalkan bentuknya walaupun dibantu dengan pengisi dan nisbah OPC: MgO 50:50, sampel dapat mencapai nilai UCS sebanyak 32.97 kPa. Penemuan menunjukkan potensi sumbangan MgO dalam penstabilan gambut dan apabila penambahan OPC sahaja tidak mencukupi untuk menstabilkan gambut. Nilai pH berbeza dari 9.0 hingga 10.1. Secara keseluruhannya, keputusan ujian UCS menunjukkan bahawa penstabilan tanah gambut menggunakan MgO dan garnet menghasilkan peningkatan kekuatan gambut yang stabil.

 

Kata kunci:  tanah gambut, magnesium oksida, kekuatan mampatan tak terkurung, pH, kelembapan

 

References

1.      Nikookar, M., Arabani, M., Mirmoa’Zen, S. M. and Pashaki, M. K. (2016). Experimental evaluation of the strength of peat stabilized with hydrated lime. Periodica Polytechnica Civil Engineering, 60(4): 491-502.

2.      Wong, L. S., Hashim, R. and Ali, F. (2013). Improved strength and reduced permeability of stabilized peat: Focus on application of kaolin as a pozzolanic additive. Construction and Building Materials, 40: 783-792.

3.      Firoozi, A. A., Guney Olgun, C., Firoozi, A. A. and Baghini, M. S. (2017). Fundamentals of soil stabilization. International Journal of Geo-Engineering, 8(1): 26.

4.      Imbabi, M. S., Carrigan, C. and McKenna, S. (2012). Trends and developments in green cement and concrete technology. International Journal of Sustainable Built Environment, 1(2): 194-216.

5.      Walling, S. A. and Provis, J. L. (2016). Magnesia-based cements : A journey of 150 years, and cements for the future.

6.      ASTM (2000). Annual book of ASTM standards, section four: Construction. American Society of Testing Materials, USA.

7.      Landva, A. O. and Pheeney, P. E. (1980). Peat fabric and structure. Canadian Geotechnical Journal, 17(3): 416-435.

8.      ASTM D 2974 (2000). Standard test method for moisture, ash, and organic matter of peat and other organic soils. Annual book of ASTM Standards, ASTM, Philadelphia, USA.

9.      ASTM D2976-71(2004). Standard test method for pH of peat materials. ASTM International, Philadelphia, USA.

10.   ASTM D 2166 (2000). Standard test method for unconfined compressive strength of cohesive soil. Annual book of ASTM standards, ASTM, Philadelphia, USA.

11.   Wong, L. S., Hashim, R. and Ali, F. H. (2008). Strength and permeability of stabilized peat soil. Journal of Applied Sciences, 8(21): 3986-3990.

12.   Saride, S., Puppala, A. J. and Chikyala, S. R. (2013). Swell-shrink and strength behaviors of lime and cement stabilized expansive organic clays. Applied Clay Science, 85(1): 39-45.

13.   Lagerblad, B. (2005). Carbon dioxide uptake during concrete life cycle – State of the art. Stockholm.

14.   Unluer, C. and Al-tabbaa, A. (2014). Cement and concrete research enhancing the carbonation of MgO cement porous blocks through improved curing conditions. Cement and Concrete Research, 59: 55-65.

15.   Unluer, C. and Al-Tabbaa, A. (2013). Impact of hydrated magnesium carbonate additives on the carbonation of reactive MgO cements. Cement and Concrete Research, 54: 87-97.

16.   Yi, Y., Liska, M., Unluer, C. and Al-tabbaa, A. (2013). Carbonating magnesia for soil stabilization, 905: 899-905.

17.   Wall, N. A. and Mathews, S. A. (2005). Sustainability of humic acids in the presence of magnesium oxide. Applied Geochemistry, 20(9): 1704-1713.

18.   Gonçalves, T., Silva, R. V, Brito, J. De, Fern, J. M. and Esquinas, A. R. (2019). Hydration of reactive MgO as partial cement replacement and its influence on the macroperformance of cementitious mortars. Advances in Materials Science and Engineering, 2019: 1-12.

19.   Dehghanbanadaki, A., Ahmad, K. and Ali, N. (2013). Influence of natural fillers on shear strength of cement treated peat. Journal of the Croatian Association of Civil Engineers, 65(7): 633-640.