Effect of Common Salt (Nacl) on Engineering Properties of Black Cotton Soil

Transcription

1 IJSTE - International Journal of Science Technology & Engineering Volume 2 Issue 01 July 2015 ISSN (online): X Effect of Common Salt (Nacl) on Engineering Properties of Black Cotton Soil Prakhar Dubey M.E. Scholar (Geotechnical Engineering) Department of Civil Engineering Jabalpur Engineering College Jabalpur, (M.P.) India Rajesh Jain Associate Professor Department of Civil Engineering Jabalpur Engineering College Jabalpur, (M.P.) India Abstract The results of laboratory investigations on the influence of Common Salt (NaCl) on the engineering properties of black cotton soils are presented in this research paper. Black Cotton soil was mixed with Common Salt (NaCl) at 0%, 2%, 4%, 6% and 8%. Common Salt (NaCl) content (by dry weight of soil) in order to establish the soil stabilizing potentials. Common Salt (NaCl) increased the Maximum Dry Density, MDD, of the soil by 1.64 g/cc to 1.79 g/cc and reduced the Optimum Moisture Content, OMC, 21.16% to 14.95%. Soaked CBR increased with increase in Common Salt (NaCl) 1.43% to 3.10%. Common Salt increased the unconfined compressive strength of black cotton soil KN/M2 to KN/M2 and Common Salt also effected Triaxial strength parameters. The results indicate that there is a potential in the use of Common Salt (NaCl) to strengthen Black cotton soils. Keywords: Common Salt (NaCl), Engineering Characteristics, CBR, Compaction, OMC, UCS, Triaxial I. INTRODUCTION Black Cotton Soils have been identified as very problematic engineering soils for structural foundations and earthworks (ASCE 2012; Sabat 2012; Osinubi 2009). When dry, BCS appear very hard with high bearing capacity to sustain imposed loads from building foundations and road pavements. But when wet, BCS absorb large volumes of water, rapidly swell, soften and loosen their high bearing capacity thereby leading to excessive settlement, differential settlement, failure of building structures, road pavements and destruction of structures built on them. These geotechnical characteristics make BCS highly problematic as foundation for buildings and road pavements. Expansive soils cover almost 20% of India s land cover and about 8% of the world s land cover. Hence, they cannot be simply ignored of construction and pavement activities because of their problematic nature. There are several methods available for improving the characteristics of expansive soil. But an efficient and cost effective method with minimum time is always the most welcome. It is extremely difficult to work with these soils. Common Salt is white in colour and is in the form of crystals. It is deliquescent and hygroscopic. It lowers the vapour pressure of water. It also reduces or prevents frost heave in soil by lowering the freezing point of water. It is very effective as dust palliative. It checks the formation of shrinkage cracks. Sodium chloride is extensively used in many chemical industries. It is also widely used in metal treating, water softening, etc. This paper indicates the results of preliminary experimental investigations on Common Salt usage in soil stabilizations. This research paper provides the effect of the Common Salt on engineering properties like compaction characteristics, CBR, Permeability and UCS of the black cotton soil. II. LITERATURE REVIEW Engineering properties of expansive clay has been in improvement to make them suitable for construction, using some short of stabilization technique. This paper mainly emphasizes on stabilization of expansive soil using locally available Common Salt. Ahmed T. M. Farid (2013) reported that expansive soil engineering characteristics improved by NaCl, KCl, CaCl2 and FeCl3. T Srikanth and K L A V Harnadh (2013) reported that some engineering properties (Maximum dry density, UCS) of expansive clay increased and Optimum Moisture Content decreased with addition of Sodium Chloride. Tamadher t. Abood*, anuar Bin kasa, zamri bin chik (2007) engineering properties of silty clay soil improved with addition of Common Salt. G.M. Ayininuola, CREN*, and O.A. Agbede, reported that Influence of Sodium Chloride on Subgrade Soil California Bearing Ratio. III. MATERIALS AND METHODS Black cotton soil used in this study was mixed with the Common Salt (NaCl) in the different proportions and a series of the laboratory tests were conducted on samples containing various percentages of the Common Salt i.e. 0%, 2%, 4%, 6% and 8% by weight of the dry soil. Following test were conducted as per relevant IS code of practice. Experiments conducted are: All rights reserved by 64

2 A. Grain size distribution. compaction characteristics. CBR(California bearing ratio test). Triaxial test. Unconfined compressive strength test. Differential Free Swell Test. Common Salt: Effect of Common Salt (Nacl) on Engineering Properties of Black Cotton Soil Common Salt is white in colour and is in the form of crystals. It is deliquescent and hygroscopic. It lowers the vapour pressure of water. It also reduces or prevents frost heave in soil by lowering the freezing point of water. It is very effective as dust palliative. It checks the formation of shrinkage cracks. Sodium chloride is extensively used in many chemical industries. It is also widely used in metal treating, water softening, Markets etc. B. Black Cotton Soil: Black cotton soil involved in this study was brought from behind Jabalpur Engineering College, near N.C.C campus, Jabalpur (M.P.). The expansive soil (BCS) is classified as clay of intermediate compressibility of CI (Gs=2.30 with 92% fines) with expansive behaviour. The physical characteristics of Black cotton soil are presented in table-1. Grain size distribution curve is shown in figure-1 Table 1 Physical characteristics of BC soil S.No. PROPERTIES Test values 1. Specific gravity Liquid limit% (LL) Plastic limit% (PL) Shrinkage limit% (SL) Plasticity index%(pi) Optimum moisture content (%) Maximum dry density (gm/cc) Strength parameters C = 1, Ø =16 9. California Bearing Ratio Test (%) Differential free swell test (%) Unconfined compressive strength (KN/m 2 ) Grain size distribution(%) Sand(%) Silt+clay (%) 8 92 C. Test Results Fig. 1: Particle size Distribution curve of BC soil Based on the research obtained from various tests conducted on BC soil, Common Salt mixes. The variation in various engineering properties of the of the BC soil are discussed below. The DFS decreases from 41% to 19%. This shows that the swelling behaviour of the soil has reduced to a great extent. Proctor compaction test results showed a decreased in OMC from 21.16% to 14.95% and increase in MDD values from 1.64 to 1.79 gm/cc with the additions of Common Salt from 0% to 8%. All rights reserved by 65

3 The soaked CBR test results indicates that the value increased from 1.43% to 3.10% as the Common salt increased from 0% to 8%. The UCS value increased from KN/m 2 to KN/m 2. Various tests were conducted on BCS mixed with Common Salt in different proportions as per relevant IS code of practice. Research test results are shown in table-2 Table 2 Research test results S.No. PROPERTIES C0% NaCl C2% NaCl C4% NaCl C6% NaCl C8% Nacl 1. OMC (%) MDD (gm/cc) Strength Parameters(kg/cm 2 ) C =1, Ø =16 C = 1, Ø =17 C =1.1, Ø=12 C=1.4, Ø=14 C=1.1, Ø=18 4. CBR (%) DFS (%) UCS (KN/m 2 ) Where:C0%NaCl=BCSoil+0%NaCl;C2%NaCl=BCSoil+2%NaCl;C4%NaCl=BCSoil+4%NaCl;C6%NaCl=BCSoil+6%NaCl; C8%NaCl=BCSoil+8%NaCl. Variation of different engineering properties are shown in figure 2 to 7 NOTE: Where: sample no.1=c0%nacl;sample no.2=c2%nacl;sample no.3=c4%nacl;sample no.4=c6%nacl; sample no.5=c8%nacl Fig. 2: Variation of OMC of BCS with Common Salt Fig. 3: Variation of MDD of BCS with Common Salt All rights reserved by 66

4 Fig. 4: Variation of UCS of BCS with Common Salt Fig. 5: Variation of DFS of BCS with Common Salt Fig. 6: Variation of CBR of BCS with Common Salt IV. CONCLUSION Based on the above laboratory investigation conducted on black-cotton soil and Common Salt (NaCl) mixes. The following conclusion can be drawn. 1) Addition of Common Salt (NaCl) into the black cotton soil has changed the proctor compaction parameters. The OMC of the BCS has decreased and Maximum dry density (MDD) increased with the addition of Common Salt (NaCl). 2) There is significant decrease in swelling characteristics of the soil. The DFS values are reduced from 41% to 19%, indicating that the degree of expansiveness has reduced from high to low. 3) Soaked CBR values have also increased with the addition of Common Salt (NaCl) content. The addition of 8% Common Salt (NaCl) into the black cotton soil, increases the CBR value from 1.43% to 3.10%. 4) There increase in the values of C & Ø on addition of Common Salt (NaCl). 5) Addition of Common Salt (NaCl) also increased the unconfined compressive strength (UCS). The UCS stabilized samples significantly increased from KN/m 2 to KN/m 2. All rights reserved by 67

5 From the above research it can be concluded that Common Salt (NaCl) has a potential to modify the engineering behaviour of black cotton soil and to make it suitable in many of the geotechnical applications. REFERENCES [1] TAMADHER T. ABOOD, ANUAR BIN KASA, ZAMRI BIN CHIK, Journal of Engineering Science and Technology,Vol. 2, No. 1 (2007) had investigated effect of adding three chloride compounds (NaCl, MgCl2, CaCl2) on the properties of silty clay soil. [2] Dr. P. D. Arumairaj and A. Sivajothi, EJGE Vol. 15 [2011], Bund. J, had investigated Effect of Sea Water on Expansive Soils. [3] G. R. Otoko, European International Journal of Science and Technology Vol. 3 No. 2 March, 2014 had investigated The Effect of Salt Water on the Physical Properties, Compaction Characteristics and Unconfined Compressive Strength of a Clay, Clayey Sand and Base Course. [4] Ayininuola Gbenga Matthew and Agbede Oluwole Akinyele, Journal of Earth Sciences and Geotechnical Engineering, vol. 4, no. 3, 2014, ISSN: (print), (online) Scienpress Ltd, 2014 has investigated Sodium and Calcium Salts Impact on Soil Permeability. [5] George Rowland Otoko and Jonathan Godlook Manasseh, GLOBAL JOURNAL OF ENGINEERING SCIENCE AND RESEARCHES, Otoko, 1(6): Aug, 2014, had investigated USE OF SALT COMPOUNDS FOR THE STABILIZATION OF NIGERIAN LATERITES. [6] Frydman, I. R. and Ehrenreich, T. (1977). Stabilization of heavy clay with potassium chloride. Journal of Geotechnical Engineering, 8, [7] Venkatabor Rad, G. (1977). Physico-chemical mechanism governing the plasticity behaviors of soils. Journal of Indian Geotechnical. 7, [8] S.A. Naeini and M. A. Jahanfar, Effect of Salt Solution and Plasticity Index on undrained Shear Strength of Clays, World Academy of Science, Engineering and Technology. Vol 49, 2011, ppr1 M. Chittaranjan, T. [9] Srikanth, B. Yamini Lakshmi & D. Pavani, Effect of sea water on some geo technical properties of clayey soil, International Journal of Earth Sciences and Engineering, Vol 04, 2011 [10] Kumpaley, NX, and Jshola, A. (1985), "The Effect of Chemical Contamination on Soil Strength", Proc. of the XI ICSMFE, Sanfrancisco, Vol.3, pp [11] Leonards, G.A. (1962), "Foundation Engineering", McGraw-Hill Book Company, New York, pp [12] Shankaraiah, B. (1996), "Effect of Electrolytes on the Behaviour of Black Cotton Soil", Indian Geotechnical Society, Madras Chapter, Vol.! pp [13] T Srikanth and K L A V Harnadh, Effect of sodium chloride on some geo-technical properties of an expansive clay. All rights reserved by 68