Soil Stabilization by Groundnut Pulp and Coconut Pulp

Transcription

1 Soil Stabilization by Groundnut Pulp and Coconut Pulp Civil Engineering RGUKT, RK Valley ABSTRACT: Soil is a base of structure, which actually supports the structure from beneath and distributes the load effectively. If the stability of the soil is not adequate then failure of structure occurs in form of settlement, cracks etc. Black cotton soil also known as expansive soil is more responsible for such situations and this is due to presence of montmorillonite mineral in it, which has ability to undergo large swelling and shrinkage. To overcome this, properties of soil must be improved by artificial means known as Soil Stabilization. The present study deals with stabilization of expansive soil using Groundnut Waste Pulp and Coconut Waste Pulp which are normally treated as waste materials after the extraction of oil. Coconut Pulp and Groundnut Pulp are blended with unmodified soil in varying percentages to obtain the optimum percentage of admixture required for soil stabilization. The results show that Maximum Dry Density and CBR values were improved after the addition of admixtures to the soil. In this comparative study laboratory tests such as Atterberg s limits, Compaction tests and CBR tests were carried out for both modified and unmodified expansive soil. Keywords: Soil Stabilization, Groundnut Waste Pulp, Coconut Pulp, Compaction Tests, CBR tests, Atterberg s limits. INTRODUCTION Expansive soils are considered problematic in geotechnical engineering since they undergo large volumetric changes due to seasonal variations in moisture. These soils can be found in many regions of the world, especially in arid and semi-arid regions. Vast areas in Africa, Asia, and America are covered with expansive soils [1]. Due to their vast availability & easy accessibility, these soils proved to be economical and so they are widely being used in construction of road embankments, airports, pavements, and other engineering structures. On the other hand, seasonal variations in moisture have surfaced the swelling and shrinkage ability of these soils [2]. Soil stabilization is proved as an effective way to address this problem. Stabilization of expansive soil has been done by addition of different types of materials like Cement [3], Lime [4], and Bitumen [5]. Nowadays, one of the common and acceptable methods of soil improvement is to use waste materials, for they are not only economical, but also help in protecting the environment. Waste materials such as Wood Ash [6], Steel Slag [7]-[8], rice husk ash [9]-[11], Silica Fume [12], Quarry Dust [13]-[14], Fly Ash [15]-[16] have been used to improve the geotechnical characteristics of expansive soils. Coconut and Groundnut are the materials which are widely used for the preparation of edible oils. After extracting oil from these nuts, the pulp is treated as a Waste material. In the present study Coconut Waste Pulp and Groundnut Waste Pulp are used for the soil stabilization. The expansive soil is replaced with different proportions of Groundnut Waste Pulp & Coconut Waste Pulp separately and various tests are carried out on the soil blended with admixtures to find the Atterberg limits, maximum dry density and California bearing ratio Values. MATERIALS & METHODOLOGY The Soil is collected from Vempalli Mandal in Kadapa District, Andhra Pradesh. The Properties of the soil sample are given in Table 1. Table 1: Properties of Soil Sample Liquid Limit (%) 46 Plastic Limit (%) 20 Plasticity Index (%) 26 MDD (g/cc) 1.27 Optimum Moisture Content (%) California Bearing Ratio (%) Soaked 0.70 Specific Gravity 2.6 Soil as per IS 1498 CI 278

2 The Admixtures i.e., Groundnut Waste Pulp and Coconut Waste Pulp are collected from local oil extraction mills located at Proddutur Mandal, Andhra Pradesh. The admixtures are air-dried, broken manually and stored at room temperature. The admixture particles were finally sieved through BS sieve 75µm. Laboratory investigations are carried out on pure soil and soil mixed with admixtures in accordance with the BIS specifications and their results were analysed and compared. Atterberg s limit tests were carried out on the material passing 425 microns for clayey soil samples with or without admixtures in accordance to IS: 2720 Part 5 [17]. Maximum dry density, optimum moisture content and California bearing Ratio values were ascertained in accordance with IS: Part 7 and Part 16 respectively [18]-[20]. The soil is tested under different proportions of admixtures and the properties of soil i.e., Atterberg limits, Maximum Dry Density, Optimum Moisture Content and California Bearing Ratio values were found and these properties are compared with the original properties of soil. RESULTS & DISCUSSION The results of liquid and plasticity limits which are stabilized with different proportions of Groundnut Waste Pulp and Coconut Waste Pulp are tabulated in Table 2 & shown in Figure 1 and Figure 2. From the results, it can be observed that liquid limit values are decreasing with the percentage increase in admixture in the soil. The Plastic limit initially decreased with percentage increase in admixture in the soil and increased further in case of Coconut Waste Pulp. But in the case of Groundnut waste Pulp, the plastic limit increased upto 4% replacement of admixture and decreased further. The Plasticity Index (P.I) decreased with increase in percentage of both the admixtures as shown in Table 2 and Figure 3. It can be also observed that reduction in Plasticity Index is less in the soil mixed with Groundnut Waste Pulp than the soil mixed with Coconut Waste Pulp. Table 2: Variation of Atterberg limits under different admixture percentages Percentage Replacement of Admixture Coconut Waste Pulp Groundnut Waste Pulp L.L (%) P.L (%) P.I L.L (%) P.L (%) P.I Figure 1: Variations of Liquid Limit with percentage replacement of admixtures 279 Figure 2: Variations of Plastic Limit with percentage replacement of admixtures

3 Figure 3: Variations of Plasticity Index with percentage replacement of admixtures The unit weight of soil is an important parameter as it controls the strength, compressibility, permeability of a soil. In the present investigation a series of compaction tests were also carried out by varying soil and admixtures (Groundnut Waste Pulp & Coconut Waste Pulp) proportions. For each sample corresponding Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) values are found. The results are presented in the Table 3. Table 3: Variation of MDD and OMC with the replacement of admixture Percentage Replacement Coconut Waste Pulp Groundnut Waste Pulp of Admixture MDD (g/cc) OMC (%) MDD (g/cc) OMC (%) The variations of maximum dry density with respective admixture content for different proportions are presented in Figure 4. It can be observed that Maximum dry density increases upto 6% replacement of admixture and decreases after 6%. It can be also observed that soil mixed with Groundnut Waste Pulp resulted in higher maximum dry density values compared to soil mixed with Coconut Waste Pulp. Figure 4: MDD Variations with Admixture replacement Improvement in the maximum dry density was observed slowly for 2% and 4% replacement of Coconut Waste Pulp and also for Groundnut Waste Pulp, but then after further increase in blend, MDD decreases. This decrease may be due to low specific gravity Coconut Waste Pulp and Groundnut Waste Pulp replaces higher specific gravity soil. The variations of optimum moisture content with the percentage replacement of Coconut Waste Pulp and Groundnut Waste Pulp in soil are given in Figure 5. The results show that soil replaced with Groundnut Waste Pulp is exhibiting greater optimum moisture content than the soil replaced with Coconut Waste Pulp. 280 Figure 5: Variation in OMC with Admixtures

4 Similarly the maximum dry density of soil replaced with groundnut is more compared to the soil replaced with Coconut Waste Pulp. As OMC decreases MDD first gradually increases and then decreases for both Coconut Waste Pulp and Groundnut Waste Pulp. This is shown in Figure 6. Figure 6: Variation of MDD with OMC The California Bearing Ratio (CBR) values for different proportions of soil and admixtures are calculated and presented in Table 4 & Figure 7. Table 4: CBR values with & without Admixtures Percentage Replacement of Admixture CBR Values Coconut Pulp Groundnut Pulp Figure 7: CBR variation with percent replacement of admixtures From the Figure 7, it can be clearly observed that as percent of admixture increases CBR values increased up to 6% and then decreased for both Coconut Waste Pulp and Groundnut Waste Pulp. In addition, it can be observed that Coconut Pulp replacement is resulting in higher CBR Values than Groundpulp Replacement in Soil. CONCLUSIONS An experimental investigation was carried out to study the improvement in geotechnical properties of an expansive soil stabilized with Coconut Pulp and Groundnut Pulp. The following conclusions are drawn from this study. The liquid limit values are decreasing with the percentage increase in both the admixtures in the soil. The Plastic limit initially decreased with percentage increase in admixture in the soil and increased further in case of Coconut Waste Pulp. But in the case of Groundnut waste Pulp, the plastic limit increased upto 4% replacement of admixture and decreased further. The Plasticity Index (P.I) decreased with increase in 281

5 percentage of both the admixtures. It was also observed that reduction in Plasticity Index is less in the soil mixed with Groundnut Waste Pulp than the soil mixed with Coconut Waste Pulp. The Maximum dry density increased upto 6% replacement of admixture and decreased further. The soil mixed with Groundnut Waste Pulp resulted in higher maximum dry density values compared to soil mixed with Coconut Waste Pulp. The results show that soil replaced with Groundnut Waste Pulp is exhibiting greater optimum moisture content than the soil replaced with Coconut Waste Pulp. It was observed that as percent of admixture increases CBR values gradually increases up to 6% and then decreases for both Coconut Waste Pulp and Groundnut Waste Pulp. In addition, it was also observed that Coconut Pulp replacement in soil is resulting in higher CBR Values than Groundpulp Replacement. REFERENCES [1] Chen F. H., Foundation on expansive soils. Elsevier Science Ltd, Second edition, New York. [2] Barazesh, A., Saba, H., and Gharib, M The Effect of Adding Iron Powder on Atterberg Limits of Clay Soils, International Research Journal of Applied and Basic Sciences, Vol. 3 (11): [3] Ahmed, B., Alim, A., and Sayeed, A., Improvement of soil strength using cement and lime Admixtures, Earth Science, Vol. 2(6): [4] Mukherjee, D., Selection & Application of Lime Stabilizer for Soil Subgrade Stabilization, IJISET - International Journal of Innovative Science, Engineering & Technology, Vol. 1 Issue 7, September [5] Gupta, Amit and Gupta B.L Road, Railway, Bridge and Tunnel Engineering, 19(3): [6] Barazesh, A., Saba, H., Rad, M. Y., and Gharib, M Effect of Wood Ash Admixture on Clay Soils in Atterberg Test, International Journal of Basic Sciences & Applied Research. Vol., 1 (4), [7] Rajakumaran, K An Experimental analysis on Stabilization of expansive soil with Steel Slag and Fly Ash, International Journal of Advances in Engineering & Technology. [8] Biradhar, K. B., Kumar, U. A., and Satyanarayana, PVV Influence of Steel Slag and Fly Ash on Strength Properties of Clayey Soil: A Comparative Study, International Journal of Engineering Trends and Technology (IJETT)-Vol.14 (2). [9] Muntohar, A. S., Utilization of uncontrolled burnt rice husk ash in soil improvement, Dimensi Teknik Sipil, Vol. 4(2), [10] Brooks, R. M., Soil stabilization with Flyash and Rice Husk Ash, International Journal of Research and Reviews in Applied Sciences, Volume 1, Issue 3. [11] Chacko, A., Roy, N., and Poweth, M. R., Effect of Rice Husk on Soil Properties, International Journal of Engineering Research and Development, Volume 9, Issue 11, pp [12] Gupta, C., and Sharma, R. K., Influence of Micro Silica Fume on Sub Grade Characteristics of Expansive Soil, International Journal of Civil Engineering Research, Volume 5, Number 1, pp [13] Indiramma, P., and Sudharani, Ch., Variation of Properties of an Expans ive Soil Mixed with Quarry Dust and Fly Ash, International Journal of Emerging Technology and Advanced Engineering, Vol. 4, Issue 4. [14] Kumar, U. A., Biradhar, K. B., Soft subgrade stabilization with Quarry dust-an industrial waste, IJRET: International Journal of Research in Engineering and Technology, Vol. 03, Issue 08. [15] Bhuvaneshwari, S., Robinson, R. G., and Gandhi, S. R., Stabilization of expansive soils using Fly Ash, Fly Ash Utilization Programme (FAUP), TIFAC, DST, New Delhi. [16] Hardaha, R. P, Agarwal, M, and Agrawal, A Use of fly ash in black cotton soil for road construction, Recent Research in Science and Technology, 5(5): [17] IS 2720: Part 5, Methods of Test for Soils: Determination of Liquid Limit and Plastic Limit. [18] IS 2720: Part 7, Methods of Test for Soils: Determination of Water Content and Dry Density. [19] IS 2720: Part 16, Methods of Test for Soils: Determination of CBR. 282