Investigating geotechnical properties of silty clay stabilized using wheat straw ash and lime.

The change of soil conditions by either physical or chemical methods to improve the soil’s capability for engineering is known as soil stabilization. The primary goals of soil stabilization are to strengthen the soil’s carrying capacity, its resistance to degradation, and its ability to absorb water. Any building project’s durability is dependent on the stability of the base soils. For this reason, soil stabilization processes must be used to ensure the soil’s strength so that it is capable of supporting the load of the superstructure, particularly within the case of soil that is highly active. It also saves an important amount of time as well as funds when compared to the method of removing and replacing the unstable soil. The subject matter addresses the full inspection of how wheat straw ash and lime can be used to enhance soil qualities and stabilize it.

that it is capable of supporting the load of the superstructure, particularly within the case of soil that is highly active.It also saves an important amount of time as well as funds when compared to the method of removing and replacing the unstable soil.The subject matter addresses the full inspection of how wheat straw ash and lime can be used to enhance soil qualities and stabilize it.
1. Introduction: Soil stability is the process of enhancing a soil's engineering characteristics on where it is located.Large amounts of silt or clay cause the geophysical characteristics of soils to change over time.These soils compress when dry, swell when exposed to snow, and become plastic when there is rainwater nearby.When constructing on soils like this, construction traffic is a critical and tough subject.In simple terms, it's frequently challenging, if not impossible, to find other uses for these materials.Such soil can be utilized to build foundations or beneath the surface of structures after being stabilized with wheat straw ash and lime, avoiding costly excavation work and transport.Utilizing wheat straw ash and lime considerably modifies a soil's properties to provide for a long-time durability and toughness, especially with regard to the effects of water and snow.The soils' mineralogical characteristics will affect how reactive they are to wheat straw ash and lime as well as the long-term strength that the stabilized coatings will develop.According to, silty clay soils with tiny particles that pass through the #200 sieve (74 mm) at least 25% of the time and have a Flexible behaviors Index of at least 10 are thought to be ideal candidates for stabilization.Significant levels of organic materials (more than 1%) or Sulphur (more than 0.3%) in the soil could indicate the need for more wheat straw ash and lime or different methods for construction.
To find out the effect of wheat straw ash and lime, on the shear strength of the ash following optimal temperature combustion, Ajay Goyal (2007) [1] performed an investigation.Waste 1327 (2024) 012010 IOP Publishing doi:10.1088/1755-1315/1327/1/012010 2 materials are burned to an appropriate temperature in order to eliminate the synthetic fibres and achieve the desired result.As a result, just 10% of the ash was filled at a controlled temperature.Humberto (2007) [2] examined research that shows variations in the concentration of soil organic carbon (SOC) and the link between agricultural leftovers and topsoil.Because of this, adding ash to the mulch process modifies the properties of the soil, indicating that mulching soil with straw extends the life of the organic material in the topsoil for a longer period of time.
In 2012, Nazar Omer Hassan Salih [3] studied the richness of the soil using the leftover wheat from every growing season of the crop.The striking results of the study show that agricultural productivity is higher in regions with leftover crops than in fields devoid of waste crops (Nazar Omer Hassan Salah, A. R. Mubarak, A.A. Hassabo).S. Andavan, Vamsi Krishna Pagadala [4] The investigation revealed that, although increased density and compaction significantly enhance the strengths of lime and fly ash stabilised soil after 7 and 28 days, the ideal lime to fly ash ratio is still significantly influenced.lime aggregation, which results in increasing lime additions to the clay.The strength decrease is roughly correlated with the solids % lowering, according to the results.In the sand example, this link was not discovered.(Umit Calik and Erol Sadoglu) [5] An expansive clayey soil including smectite group clay minerals like montmorillonite and nontronite was stabilised using perlite and lime in this study.Test mixes were created for this purpose by adding 0, 10%, 20%, 30%, 40%, and 50% of perlite to soil that had an optimal lime ratio of 8%.Amit S. Kharade (2014) [6] Gathering bagasse ash from the sugarcane industry helps to stabilise the soil.Because samples for stabilisation were gathered from the Maharashtra sugarcane sector, this study addresses the issue of sugar cane disposal.
The silica-rich fibrous substance is found in the bagasse ash.To determine the potential of the stabilised material, laboratory experiments including the Atterberg's test, UCS, compaction, and CBR were carried out.It was found through tests involving partial replacement of various percentages that the significant chemical, physical, and geotechnical qualities of the soil are enhanced by 6% bagasse ash.According to the findings of the first investigation, the bearing capacity and compressibility of black cotton soil are low.Ash increased both the bearing capacity and the shear strength.The substance that was produced strengthened the black cotton soil's elasticity.Andrzej k.Bledzki (2010) [7] Examine the possibility of employing wheat husk as a reinforcement in plastics through electron microscopy.Rye and wheat husks are among the materials used in this investigation.The electron microprobe analyzer examined the mixture's chemical composition while the equipment monitored and assessed the mixture's thermal and physical characteristics.The soft wood material with a particle size distribution between 100 and 200 micrometres is what's responsible for the improvement.According to research on impact strength and tensile strength, wheat husk has a higher silicon surface area than other materials.Ogunniyi Jumoke Esther (2013) [8] observed that adding wheat straw ash to the farmed fields had positive effects.In order to assess the soil's quality, it was treated with several nitrogen sources.Although adding straw always has favourable results, the sluggish pace of decomposition in this case is the issue.This is primarily due to the ratio of carbon to nitrogen.Thus, a 17-pot experiment with four imitations was carried out.150 grammes of soil and 1.125 grammes of straw were used in each pot, and the moisture content was set to 80% of the field capacity.Compared to maize straw, adding wheat straw increased the amount of microbial biomass that accumulated.Jiguang Zhang (2016) [9] examines the tobacco field through an analysis of the impact of adding straw to the soil.Over a three-year period, straw from wheat and maize was gathered in the Zhucheng area of Southeast Shandong province.Seven treatments are applied to this soil: none at all, use both straws at medium level, and use it at higher level.Every year, organic fertilisers are applied to the crops and the nutritional value is measured.That being said, the addition of both maize and wheat straws changed the parameters associated with soil organic carbon.The field study indicates that maize straw improves soil enzymes more effectively than wheat straw.This is because maize straw makes the soil more stable in its aggregate form.Furthermore, when maize was incorporated, the nutrients and value of SOC were greater.Arunav Chakraborty (2016) [10] investigates the soil in great detail, which puts civil engineers in danger.This instance of cost-effective soil stabilisation involves the use of sugarcane straw ash.Increased emphasis is placed on improving the geotechnical qualities by adjustments to admixture amounts and curing times.Cane ash is already used to a sufficient extent, however in this case, various amounts of straw ash are taken through testing on various days.As a result, several tests are looked into, including the proctor, sieve analysis, Atterberg limits, CBR, UCS, and CBR value.Three, five, and seven days of curing were used for the unconfined compressive strength test.The findings show that the UCS value increases with a longer curing period.But the highest CBR value is obtained with an admixture addition of 10%.
Mr. Santosh (2015) [11] used wheat husk ash and slag from the blast furnace-a byproduct of the iron industry-to conduct an experiment.This is due to the fact that stabilisation by admixtures is more beneficial than bituminous, mechanical, cement, lime, and earth reinforcement methods.The primary cause of stabilisation is the unique mineral found in black cotton soil that has the ability to absorb water.The result is shrinkage and contraction in the pavement, manifested as cracks.Therefore, research is done on adding admixture to stabilise the expanding soil.Utilising industrial waste is the primary goal.Here, the potential of the used material is examined using the standard proctor test, UCS, specific gravity, grain size distribution, and liquid and plastic limits.Stress against the number of days was used to model the compaction test.The findings demonstrated that 9% WHA and GBS added to the soil can reduce its water content up to a certain point.With a 7-day curing period, this research is appropriate and yields the best outcomes.Consequently, 9% is the ideal percentage to improve the necessary soil's qualities.Shamle, N.J(2014) [12] Using fluorescence spectroscopy, the silica was recovered from the various industrial ashes.The calcination technique is used to extract the amorphous silica from the ash, wheat husk, and rice husk ash.These serve as the raw materials.Therefore, the silica is obtained by reducing the pH and combining it with sodium hydroxide.In this work, the separated amorphous silica from various ashes is compared to determine which is preferable.Finally, it is determined that, of the three ashes, ash husk ash is the most yielding and acceptable material with the fewest contaminants.M. Chittaranjan, M. Vijay, D. Keerthi (2011) [13] examined the use of agricultural wastes as soil conditioners.
Groundnut shell, rice husk ash, and sugar cane bagasse ash, all gathered from the industry, are utilised in this study to stabilise the poor subgrade soil.A CBR test is performed for each percent of the soil after it has been mixed with the three wastes at different percentages-0%, 3%, 6%, 9%, 12%, and 15%.The test results indicated a redesign of the CBR value with an inclined waste percentage.Pinar Terzioglu (2012) [14] utilises the transform of Fourier series to create the magnesium salt from the wheat husk ash.This research is being conducted in an effort to address the waste issue and make a significant contribution to the industry's recovery.To extract silica, wheat husk is burned to the ideal temperature and then chemically reacts with sodium hydroxide over a flame.The ash that was recovered was made up of several components, with silicon dioxide making up the largest portion at 44%.The resultant ash has an entirely amorphous form.This component can be used to create the desired results.The findings demonstrate that the chemical makeup of magnesium silicate is unaffected by investigation.Amu (2011) [15] experiments with several tests, such as the CBR test, the moisture content test, the specific gravity test, etc., to ascertain the geotechnical qualities of the soil.Sugarcane ash is added as a stabiliser.This experiment was conducted using lateritic soil.pozzolan substance that, at a given temperature, has a Cementous value.A decrease in the soil's plasticity index was observed across many samples, suggesting that the soil has improved.Also, the CBR value for samples A, C, and B was 400% and 220% higher, respectively, than that of the unstabilized samples.In samples A, B, and C, the corresponding increases in sample strengths were 79.64 to 284.66kN/m2, 204.86 to 350.10kN/m2, and 240.4 to 564.6kN/m2.The basic factor that determines a clayey soil's consistency is hence its unconfined compression strength.The test's results corroborate the studies showing how effective cane ash is as a stabiliser for soils high in iron and aluminium.Collected from agricultural areas, wheat straw is burned at 600 degrees Celsius to create fine ash.The most silicon is found in this ash, which increases the fertility of the soil.Burning crop waste in preparing wheat from grain results in the creation of wheat straw ash, which is basically a product of waste.20 to 22% of paddy contains wheat straw, and when burned, roughly 25% of the entire wheat husk turns into ash.There is no plastic in it.Additionally, according on the degree of heat at which it burnt; its characteristics changed.WSA's geotechnical characteristics are mentioned in Table 1. Figure 2 shows the particle size distribution curve for wheat straw ash.

Material Combination:
According to the current research, Wheat straw ash and lime, two stabilizing materials, have both been investigated separately and in mixture to see how they impact the engineering qualities of silty clay.First, the effects of adding lime and wheat straw ash to silty clayey soil are examined separately.This is followed by an examination of the usage of the chemical additive lime at various percentages in clay-WSA.The impact of adding all the additives clay, WSA, and lime is then researched.Several experiments were conducted on the mentioned prepared soil samples to determine their geotechnical engineering qualities.To evaluate how much and with what components the expanding soil is more and less stable, the experimental data acquired are compared.Our research is particularly concerned with determining the Atterberg consistent limit, ideal moisture level, maximum dry density.The lab tests were carried out in the way that is described below.1.Furthermore, consistency limit (liquid limit) tests were carried out on all the clay-WSA and clay-lime mixes in order to determine any ideal mix that provides good geotechnical property, strength, and deformation characteristics because the compaction results don't give any optimal value as discussed above.

Results and Discussions:
The previous part of the paper covered the index of characteristics and engineering characteristics of the silty clay, wheat straw ash and lime.In an earlier part, it was talked about how to identify the best mixes and how to carry out tests for flexibility, specific gravity, grain size distribution curve, the California bearing ratio, the liquid limit, the plastic limit, compaction, and unconfined compressive strength.The following sections describe, we'll go over the findings of these studies as well as how adding admixtures like lime and wheat straw ash modified the engineering properties of silty clay.

Particle size distribution Analysis:
Figure 2 shows how the particle size distribution curves of silty clay and wheat straw ash were analyzed.Wheat straw ash's particle size variation curve indicates that it is not well-graded, while silty clay soil particle size distribution shows that a significant portion of its particles are of the clay size range.
The way that soils respond in practical applications can be greatly influenced by the distribution of particle sizes.The composition and arrangement of the mineral particles that make up soils greatly affect the soil's characteristics.Within a single soil sample, particles can vary in size from exceedingly coarse (>100mm) to extremely small (<2micron).
Larger particle sizes in soils result in more inter-particle friction, which makes them stronger; finer soils are more water-sensitive.Geotechnical engineers can make more educated decisions about the uses of soil by using the particle size distribution of a soil to forecast its strength and qualities.
We can calculate the percentage of soils in each size range using the particle size distribution.
A variety of particle sizes can be represented by each fraction or interval that is created during soil sample separation.
A chart is typically used to display the findings of an analysis of particle size distribution.The horizontal axis is the particle size plotted on a log scale, and the vertical axis is typically the cumulative percentage (by weight) that is finer than a certain size.properties.In clay, lime increases the optimum water content while decreasing the maximum dry density.The maximum dry density decreases to 1.568 g/cm3 when the lime percentage increases to 5%, whereas the optimal moisture level increases from 19.53% to 22.74%.The collection of particles that occupy greater amounts of space changes the clay's gradation, and replacing soil particles with a volume of lime with a relatively low specific gravity also results in the drop in dry density at its maximum.
The water relationship that occurs when lime is added, along with the toxic interaction between clay particles and the lime, are responsible for the increase in the ideal water level.

C. Clay-WSA-Lime mix:
Lime has been added to the combination of 82% clay and 15% WSA to further enhance its unique features.Figure 5, illustrates the features of compression for the percentages of 10, 11, 12, 13, 14 and 15 of lime applied to the clay-WSA mixture.As the lime component rises to 9%, the clay-WSA mixture's highest dry weight reduces from 1.33 g/cc to 1.28 g/cc and its ideal water content rises from 30% to 33%.Due to floating of the particles and a lesser specific gravity of lime, the highest possible dry density has decreased.The reaction that occurs between particles of clay and the lime and because of moisture propensity upon the presence of lime causes an increase in the ideal moisture level.The impact of WSA stabilized soils on the liquid limit (LL) of soils and WSA mixture is depicted in Figure 6.It has been demonstrated that an increase in LLs and plastics limits decreases the flexibility of WSA stabilized-residual soils.WSA reduces the soil's liquid limit.In general, 10-15% WSA are optimum for decreasing the flexibility of the soil.A reduction in the liquid limit demonstrates progress.The liquid limit of silty clay soil is reduced when WSA is added from 5% to 20%, Because of the use of WSA, the liquid limit is reduced.This decrease in liquid is due to the addition of coarser particles of wheat straw ash.To find the best mixture for stabilizing clayey soil, liquid limit experiments are performed on clay mixed with various concentrations of lime.Clay is mixed with lime in percentages of 0, 3, 6, 9 and 12, and liquid tests have been conducted.Figure 7, illustrates the compositions' liquid limit.The maximum liquid content of clay-based soil is reduced by the use of lime from 6 to 12% as the proportion of lime increases to 3%. Figure 0 shows how the clay-lime mix's liquid limit have changed over time.Due to a reduction in the depth of the twice diffusion layer and its flocculation of clay fragments, the plastic limit increased following the addition of lime.The pozzolanic reaction between WSA and soil particles may be responsible for the increase in soaking CBR value with the addition of WSA.When lime is added to soil that is clay-like, the soaking CBR value rises to 7.5%.The heavy compaction of clay particles between the lime particles is what causes the increase in the soaking CBR when WSA and lime are added simultaneously.This rise rises above that caused by the presence of fly ash alone.This results from the pozzolanic and chemical reaction between the particles of clay, WSA, and lime.
Soil or bitumen pavement's carrying capacity is assessed using the California carrying Ratio test.Roads and pavements' subgrade strength value can be ascertained using a penetration test called CBR.To calculate the thickness of the pavement and the different subgrade layers, test findings are utilized in conjunction with curves.
To determine the CBR of a material that must be utilized as the subgrade for flexible pavements, a CBR test is performed.However, resilient modulus is the real number that indicates how strong the subgrade material is.While extremely differentiated, CBR is not like it.Additionally, for each subgrade thickness, curves for the CBR are drawn versus the anticipated traffic (million axles annually) in literature.If we know the CBR of our material and the design traffic, we can read the required thickness for which we need to design the subgrade layer.Therefore, using CBR-which is readily testable on site-instead of delving into the intricacy of robust modulus calculations is preferred.
By definition, CBR is the percentage of the actual crushing strength of the rock divided by the opposing bearing stress that a standard penetrator experiences after penetrating the rock a distance of 2.5 cm.

Conclusions:
According to the results of this work, WSA replacement in varying percentages has a variety of impacts on loose soil.Following testing, it was discovered that 15% is the appropriate percentage of WSA for stabilization of soil.
1. Clay's maximum dry density is decreased by adding wheat straw ash and lime, both individually and in combination.Lime has the greatest impact on MDD reduction, followed by WSA.
. When WSA and lime are added to clayey soil, either separately or in combination, the ideal moisture content rises.

3.
Due to the decreasing pattern of MDD, compaction characteristics do not provide a clear understanding of the ideal additive content for stabilizing clayey soil.In order to further improve, consistency limit and plasticity index were used.

4.
The liquid limit lowers with the addition of wheat straw ash and lime.
The material was taken out of the Nandiya region of Madhya Pradesh, India fig.1.The samples were sent to the university's lab after being stored in a plastic bag for examination.The soil's range of particle sizes is shown in Figure 2. Based on the amount of particles distributions and Indian Standard IS: 1419-1970, the soil was classified as Silty Clay.1327 (2024) 012010 IOP Publishing doi:10.1088/1755-1315/1327/1/0120105

Figure 1 :
Figure 1: Area of soil collection b.Wheat straw ash: WSA has a powerful porous effect.It's used for many different uses.The main source of nourishment for both living and non-living things, it is mass-produced.It has a nutrient content per gramme of about 3.5 kcal.Farmers constantly burn waste in the fields after harvesting grains, leaving its by-product behind.This study looks into how WSA affects soil.

2 .
All the ideal mixtures of clay-WSA, clay-lime and clay-WSA-lime, were subjected to soaked CBR and permeability experiments in order to assess the effects of admixture addition on the features of CBR and permeability of clayey soil selecting the most reasonable and environmentally friendly material for stabilizing clayey soil for use in concrete applications individually and in combined.

3 .
In order to evaluate the effects of admixture addition on the characteristics of CBR and permeability of clayey soil, all of the ideal mixtures of clay-WSA, clay-lime and clay-WSA-lime, were subjected to unsoaked CBR and permeability experiments.This allowed 1327 (2024) 012010 IOP Publishing doi:10.1088/1755-1315/1327/1/0120108 for the selection of the most reasonable and environmentally friendly material for stabilizing clayey soil for use in concrete applications, both individually and in combination.

Fig. 2 .Figure 3 ,
Fig. 2. Particle size distribution 2. Compaction characteristics: A. Clay -WSA mix: Figure 3, demonstrates the impact of varying quantities of WSA, Soil-WSA combinations on the compaction parameters of the examined soils.The graph depicts that adding WSAin various proportions such as 5%, 10%, 15% and 20% to soil increased OMC from 18% to 25% and lowered MDD from 1.63g/cc to 1.31g/cc.Due to WSA's lower specific gravity than silty clay soil, the maximum dry density with WSA addition decreases.As a result of WSA's higher optimal moisture content than clay, the composite's optimum moisture content has increased.

Fig. 3 .
Fig. 3. Clay and clay-WSA mix curves for compaction.B.Clay-Lime mix:Before doing compaction testing, liming of the silty clay soil is done in percentages of 3, 4, and 5. Figure4, illustrates how lime adding changes silty clay soil's compacting

Table 1 .
Geotechnical properties of Clayey Soil and WSA used for test.Lime, which is formed from crushed limestone, is one of the very first building materials utilized by human.The ancient Greeks used lime for constructing their roadways.As one of the strength brought on by the reaction of chemicals with topsoil and limestone elements, lime is favored for soil stabilization.As a result of its reaction producing strong bonds and establishing a contrast with the durability of other substances, expensive lime is chosen as one of the additives in the current research while being expensive.The manufactured dry white powder lime used in the present study has a specific gravity of 2.1 and a pH of 11.1.Table2.lists the characteristics of lime, including its chemical structure.
c. Lime:very first stabilizers, limestone is still used nowadays in many building projects, including those involving roads, railroads, airports, foundations, and slope safety.Due to its fast and significant 6 increase in

Table 2 .
Properties of Lime

Table 3 .
Various materials were used in the experimental study.

Table 4 .
Indian specifications for several testing.4. Methodology: Mixing soil with different proportions of WSA and Lime mixed soil samples.