Optimum Lime Research Articles

Mechanism of improvement and best-fit models for the prediction of geotechnical properties of lime stabilized expansive soil used in pavement subgrade

The performance of a pavement mainly depends on the quality of the subgrade layer. Expansive soils (ES) are extensively found worldwide including Pakistan. The inadequate strength and swelling behaviour of these soils are the main problems in any road construction project. Several researchers in the last decades have attempted to improve expansive soil utilizing various materials such as lime, brick kiln dust and fly ash. The purpose of this research was to evaluate the effect of lime on the engineering properties of the ES of a highway subgrade in the Sialkot region of Pakistan. The influence of different lime dosages (0%, 2%, 4% and 6%) at curing ages (1, 7, 14 and 28 days) has been examined by pH tests, plasticity tests, compaction tests, unconfined compressive strength (UCS), free swell index, and California Bearing Ratios (CBR). A field CBR and plate load test (PLT) on the natural soil and optimum lime-treated soil with various curing periods have been carried out for applicability as subgrade material. The test findings demonstrated that higher lime dosages increased the strength and ultimate bearing capacity (𝑞𝑢𝑙𝑡) of improved ES and at the same time decreased the free swelling index (FSI), optimum moisture content (OMC), maximum dry density (MDD) and permanent deformation of the subgrade soil. The UCS values of soil treated with 2%, 4% and 6% lime increased almost by 324%, 523%, and 249% for unsoaked samples and 285%, 351% and 231% for soaked samples respectively as compared to the plain soil at 28 days curing period. The laboratory CBR values significantly increased 2.35-8.50 times and field CBR improved 5.6 times as compared to the plain soil. The 𝑞𝑢𝑙𝑡 of lime-treated soil increased by 162% as compared to the plain soil and permanent deformation reduced from 33 mm to 2 mm after 28 days. Furthermore, equations were developed to estimate the best fit for the prediction of various geotechnical parameters and coefficient of determination (R2 ) values for all equations were found higher than 0.90. From the results, it has been concluded that adding the optimum lime content of 4% by weight satisfies the requirement for the subgrade construction of highways and the developed expressions can provide a scientific basis for estimating the geotechnical parameters.

Penggunaan Kapur Palupuh dan Kapur Rao-Rao pada Asphalt Concrete - Wearing Course

Indonesia has the many area of the lime production including in the West Sumatra Province. The use of lime as a filler in asphalt mixtures is expected to improve the performance of asphalt mixtures. There are two types of lime used, namely Palupuh and Rao-Rao limestone. This study aims to see the effect of using these 2 types of lime as a filler on Asphalt Concrete-Wearing Course (AC-WC) pavements mixture. The bitumen used is Pen 60/70. Marshall testing was carried out to see the characteristics of the pavement mixture. From Marshall's testing on a pavement without lime, has an optimum asphalt content of 6.015%. Furthermore, with a variation of lime 0%, 25%, 50%, 75%, 100% by weight of filler for both types of lime gave an optimum lime content yield of 50% with an increase in stability of 12.024% and flow of 19.375% for Palupuh lime. Meanwhile, the use of Rao-Rao lime cannot improve the Marshall stability of the AC-WC pavement mixture

Effect of leachate contamination in municipal solid waste on clay liner characteristics

Landfill leachate is generated as a consequence of water percolation through the solid waste, oxidation of the waste, and corrosion of the waste. Under-designed landfill sites allow the leachate to easily pass through the soil strata. To identify the effect of contaminants on the engineering properties of the clay liner, a pilot-scale lysimeter was developed. Experiments on two types of soils polluted with leachate were conducted which included silty clay and soil enhanced by chemical stabilization. Lime and silica fume are used as reactive barriers in landfill earthen liners. The leachate generated was monitored periodically and sampled for (pH, Electrical conductivity, Chemical oxygen demand, Chloride, Total dissolved solids, and total suspended solids). Lime (L), silica fume (SF), and lime-silica fume (L-SF) mix have been used for stabilizing soil. Three percentages were used for lime (2%, 4% and 6%) and three percentages were used for silica fume (3%, 5% and 7%) and the optimum percentage of silica fume (5%) was mixed with the proportions of lime. The optimum lime values are 4% from the research and 5% for silica fume. Soil samples were analyzed over a maturation period of 135 days for each run to identify the chemicals and their effect on the soil characteristics. The plasticity index of the stabilized soil continues to decline until it reaches 36% over the 135 days of the maturing period. Furthermore, an increase in silty clay soil hydraulic conductivity was observed from 3.3 × 10−6 cm/sec to 5 × 10−6 cm/sec at 135 days of maturation. Whereas there is a sharp decrease in hydraulic conductivity to achieve a maximum value in the stabilized soil (1.25 ×10−10 cm/sec). Based on laboratory test results, it can be concluded that soil stabilization can improve the geotechnical properties of landfill earthen liners due to pozzolanic reactions.

Effects of the Types and Amounts of Clay Minerals on Durability of Lime-Stabilized Clay Soils

Although the interaction between clay minerals and lime is the most effective factor in lime stabilization techniques, it has not been deeply evaluated. This research study investigated the microstructural characteristics of lime-stabilized Bentonite and Kaolin soils using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX) analyses. To consider the variation in clay mineralogy, these soils were mixed at varied ratios, stabilized, and then subjected to a durability process. The microstructural findings showed that the pozzolanic reactions with lime did not occur or occurred at a low level for Bentonite soil. However, they occurred at a very high level for Kaolin soil. The durability test confirmed the microstructural results and showed that the samples in which Bentonite soil had a share of 40 to 100% by dry weight of the soil did not last with any percent of lime. When the Kaolin soil content reached 100% by dry weight of the soil, the specimens lasted in the best possible way, even with 4% of the lime. This study concluded that the determination of optimum lime content based on the amounts and types of soil clay minerals is an important innovation for geotechnical projects and may be very cost-effective.

Determination of Lime Requirement with Compost on Acidic Ultisols for Wheat Crop in the Gurage Zone of Ethiopia

Acidic soil adversely affects the plant growth and production. Various ameliorating strategies are known, but the optimum rate of lime and compost rate determination for better nutrient management and production in acid Ultisols was not well studied, so the main objective of this study was to determine optimum lime and compost rate for wheat production. A pot experiment was performed on the soil collected from Yefereze (Cheha District). The incubation trail was conducted in factorial combination of four level lime (8.44, 6.33, 4.22, and 0 t·ha−1) and compost (15, 10, 5, and 0 t·ha−1). The sixteen treatments were arranged in completed randomized design (CRD) with triplicate replications in the greenhouse. After 75 days, each pot that was planted with wheat and crop performance had been monitored. The textural class of the soils of the experiment was clay with strongly acidic pH. The organic carbon (2.17%) and total nitrogen content (0.17%) status was medium. The available phosphorus (Av. P) contents were very low (1.63 ppm). The experimental study result revealed that all the three rates of lime and compost continuously improve the soil pH throughout the study periods and the maximum soil pH (6.53) was obtained in combination of 8.44 t·ha−1 and 10 t·ha−1 lime and compost, respectively. The compost amended treatment indicated slight improvement in soil reaction which assert that using compost alone did not reduce soil acidity within 75-day periods in strongly acidic soil condition for suitable wheat production. Liming alone or integrated application increases soil pH (4.69 to 6.53), cation exchangeable capacity (CEC) (27.18 to 31.58 cmolckg−1), exchangeable calcium (3.56 to 8.43 cmolckg−1), available phosphorus (Av.P) (1.63 to 5.27 ppm), total nitrogen (TN) (0.19 to 0.24 ppm), and exchangeable acidity reduced (0.73 cmolckg−1 to trace). Integrated application of 8.44 and 5 t·ha−1 lime and compost rates improve the overall soil property and maximize the wheat yield by 24.26%. Generally, the limiting factor for wheat production of the study area was the acidity of the soil. The combined application of lime and compost raised the pH and improved the suitability of the soil for wheat production. However, the status of Av. P was low after the amendment, and it is advisable to integrate phosphorus containing fertilizer in addition to lime and compost for optimum and sustainable production of wheat in the study area. Since the incubation and greenhouse experiment were conducted in a controlled environment, there is a need for field verification. It is also advisable to assess the economic feasibility of the different rates of lime and compost for an appropriate soil management decision.

Internal Erosion Stabilization of Cohesionless Soil Using Lime

Soil embankments are valuable for the adequate reserve and supply of water to multiple industries. However, they are susceptible to internal soil erosion, which may ultimately lead to structural collapse. To counteract this issue, soil stabilization is practiced in the construction industry. This paper proposes the internal erosion stabilization of cohesionless soil using quicklime. For this research, two cohesionless soil types were investigated and treated with quicklime: poorly graded and well-graded cohesionless soils. For poorly graded soil, the lime percentage varied from 0.0% to 6.0% based on the soil’s weight, while for well-graded soil, it ranged from 0.0% to 3.0%. All the soil specimens were cured for 24 h and tested using the hole erosion test (HET) to replicate the internal erosion effortlessly. The analyzed results demonstrated the efficiency of quicklime as an internal erosion stabilizer for cohesionless soils. The optimum lime content for poorly graded cohesionless soils was 5.0%; for well-graded, the percentage was approximately 3.0%. Moreover, adding lime significantly improved the strength, critical shear stress, and erosion rate index of the soil.

Enhancing the strength of expansive clayey soil using lime as soil stabilizing agent along with sodium silicate as grouting chemical

The expansive clayey soils have been found plenty in the southern semiarid region of Tamil Nadu. This study deals with the strength enhancement of the locally available expansive clayey soil by using hydrated lime powder as a stabilizing agent and sodium silicate as a grouting chemical. Standard proctor test and unconfined compressive strength test were carried out to determine the optimum percentage of lime content for soil stabilization, which was 10%. An unconfined compressive strength test was carried out by varying the proportion of sodium silicate to 2%, 4%, 6%, 8%, and 10% by keeping optimum lime content. California Bearing Ratio (CBR) test was conducted to determine the soil's load-carrying capacity for both the untreated soil and treated soil. The CBR value for soil treated with lime content is 5.2 times the CBR value of untreated soil. Similarly, the CBR value for soil treated with an optimum proportion of lime and sodium silicate is 7.86 times the CBR value of untreated soil.

Bauxite residue as a binary additive in lime treated soil composites

Industrial solid wastes have been valorized as binary and ternary admixtures in earth modification and treatment of problematic soft soils. In this investigation, an industrial waste from the aluminium industry, viz. Bauxite Residue was assessed to understand its efficacy as a binary addendum to lime in improving swelling soils. The novelty of this investigation is its focus on the combination of a scientifically established lime content viz. optimum lime content and low doses of Bauxite Residue, which seems to be virtually absent in published literature. The investigational trial explored the unconfined compression strength and stress–strain characteristics of the lime treated soil composites, treated using combinations of 7% lime and 0.25%, 0.5%, 1% and 2 % bauxite residue. The lime treated soil composites were moulded in to cylindrical specimens of 38 mm diameter and height of 76 mm, cured in air-tight polyethene covers for two hours, three, seven, fourteen and twenty-eight days and tested for their unconfined compression strength. The outcome of the investigation was also compared with some previous investigations from available literature. It was revealed that 2% bauxite residue blended lime treated soil composites was the most ideal out of all combinations studied for developing maximum strength of the lime treated soil composites. It was also noticed that bauxite residue blending of the lime treated soil composites did not affect the strength progression trends irrespective of the bauxite residue content and post peak stress–strain behaviour of the lime treated soil composites improved with increasing bauxite residue content.

Hydration of lime—marine sediment blends: Influence of mineralogical composition and lime content

There is a need to find alternatives to the extraction of non-renewable mineral resources for the production of new binders. Some specific building materials such as plant-aggregate-based concretes do not require high-strength binders. In this context, the lime-pozzolan technology, inherited from Roman times, can help reduce the carbon footprint of finished materials by the use of low amounts of lime. In this paper, three different marine dredged sediments were used as natural alumino-silicate resources and blended with hydrated lime. Based on previous literature dealing with the pozzolanic activity of cristallized minerals, the sediments were reduced to micronized powders. The hydration of these systems was investigated through hardening and reaction kinetics up to 365 days at 20 °C and 50 °C. The sediments used revealed two kinds of mineral assemblages and the best pozzolanic reactivity was found with quartz-rich sediments. In addition, the optimum lime content was found to be 20 wt% until 180 days.

Assessment of a Multi-Stage Wet Scrubber Performance Based on Characteristics of Scrubbing Solution

This paper presents the wet scrubber performance on acid gas absorption based on pH and conductivity measurements. The waste combustion system comprised of a CFB combustor in which mainly plastics waste was loaded into the riser (15 cm ID x 1.5 m long). The scrubbing experiments were conducted using a two-stage wet scrubber used as air pollution control device. The performance of the wet scrubber system was assessed by studying the changes in the pH and conductivity. The scrubbing solution was prepared using lime. The optimum lime concentration was obtained from bench experiments, giving an initial pH of up to 13. The scrubbing solution samples were collected from the solution tanks after every 2 minutes for 40 minutes. The scrubbing solution flow rate ranged from 0.53 to 0.95 L/s while the gas flow rate from the blower was kept constant at 16 m/s. It was observed that the pH of the scrubbing solution for both stages decreased to neutral range with increasing operation time. The decrease in pH and conductivity was initially faster before increasing slightly due to deposition of fly ash. It was concluded that the multi- stage wet scrubber is capable of removing toxic acid gas and particulate matter

Stress-Strain Characteristics and Mineralogy of an Expansive Soil Stabilized Using Lime and Phosphogypsum

The study involved the utilization of an industrial waste product, Phosphogypsum (PG) as an additive to lime for the stabilization of soil. Three lime dosages, viz. initial consumption of lime (ICL), optimum lime content (OLC) and less than ICL (LICL) were adopted for stabilizing the soil. The study investigated the stress-strain characteristics of soil composites stabilized with these three lime contents modified with optimum dosages of PG. Mineralogical studies were performed on the spent samples used for a series of determinations of unconfined compression strength tests with various combinations of lime and optimum PG content. The addition of an optimum dosage of PG resulted in an early strength gain of 8.8%, 14.1% and 13.9% and a delayed strength gain of 9.9%, 19% and 19.7% for 3%, 5.5% and 7% for the lime-stabilized soil, respectively. It was found that the addition of PG to the lime resulted in enhanced stiffness, residual strength and reduced brittleness due to the PG amendment of the stabilization reactions. However, in terms of the overall improvement of soil properties, the most favorable benefit was obtained by optimal PG modification of ICL rather than OLC. Microanalysis of the X-ray diffraction scatter also supported the results revealed through stress-strain characteristics. ICL with its optimal PG dosage showed a better progression of pozzolanic reactions when compared to the other two in terms of reduction of peaks of soil minerals and increase in peaks of CSH.

Compressive and tensile strength of aeolian sand stabilized with porcelain polishing waste and hydrated lime

The improvement of sandy soils by incorporating new stabilizing agents in a physical and/or chemical process has become the subject of many studies in recent decades. In addition, the use of industrial wastes in this process can bring significant benefits to the environment and savings in natural resources. This work aims to evaluate the implications of incorporating porcelain polishing waste (PPW) and hydrated lime on the mechanical properties of an aeolian dune sand from the city of Natal/RN. Tests of unconfined compressive strength and split tensile strength were performed on compacted soil specimens with different contents of PPW (10%, 20% and 30%), hydrated lime (3%, 5% and 7%) and relative densities (25%, 50% and 75%). To evaluate the effects of each factor, the Response Surface Methodology with Central Composite Design was used. The results have shown that all three factors have a positive effect on the response variables. The highest strengths were obtained in regions combining high values of relative density and PPW content and an optimum lime content was found. An inversely proportional correlation and good fit to the experimental data was obtained between the strength values and the porosity/binder index (η / Biv). The strength gains were attributed to densification of the soil structure and cementation of the particles by the compounds formed in the reaction between lime and PPW. The results also showed an increase in the strength with curing time, indicating a pozzolanic activity of the mixtures.

Mechanical characterization of lime-stabilized rammed earth: Lime content and strength development

Earth construction techniques, such as rammed earth, are present worldwide due to the availability of the material and its mechanical performance. Today they are also attracting attention as an environmentally friendly way of building, although additivation is usually needed. Lime stabilization is an interesting option with long tradition, well-known capacity to improve soil properties and limited environmental impact. This study evaluates the effect of increasing lime contents in the compressive strength and stiffness of rammed earth, and analyzes the strength development process of the material. Carbonation depth and ultrasonic pulse velocity are also evaluated due to their relationship with the mechanical behavior. The results show that 12 % lime maximized the compressive strength and stiffness of the rammed earth material; the strength was mostly developed during the first month but needs over a hundred days to be fully developed. A good linear correlation between the ultrasonic pulse velocity and the compressive strength is observed. • Lime stabilization improves rammed earth strength and stiffness. • There exists an optimum lime content that must be evaluated before construction. • Compressive strength and stiffness follow an exponential development over time. • Long curing periods, over 100 days, needed to develop maximum strength. • UPV tests are useful to estimate the mechanical properties of rammed earth.

Effects of Lime Addition on the Plasticity of Tropical Clay Soils with Different Mineralogical Composition

The influence of hydrated lime on the plasticity of six tropical soils from Sudan having different mineralogical composition and constituents has been studied. The mineral constituents of the clay fraction of these soils vary from predominantly montmorillonitic, predominantly kaolinitic to mixed minerals. Lime has been added in varying percentages by weight and Atterberg limits have been determined for the untreated and lime treated soils. The test results have shown that on treatment with lime the Liquid Limit (LL) has decreased, the Plastic Limit (PL) has increased and the Plasticity Index (PI) has subsequently decreased for all the soils. The Optimum Lime Content (OLC), the Initial Consumption of Lime (ICL) and the Lime Fixation Point (LFP) have been defined and determined. A very good relationship between ICL and the Activity of the untreated soils (Ae) has been found out. The drop in PI and LL upon treatment with OLC is directly proportional to PI and LL, respectively. Montmorillonitic clay soils react faster with lime compared to kaolinitic clays. The OLC is higher for montmorillonitic clays compared to kaolinitic clays.

Strength enhancement studies on expansive soil by utilization of unburnt agricultural waste

In order to determine stability and to support any structure underlying soil bearing strength is necessary. Of all the soils available in India black cotton soils rich in montmorillonite is one of the most problematic and expansive soils as they are every dangerous for construction because of its swelling and shrinkage properties. Such types of soils can be stabilized using locally available waste materials either agricultural or industrial. The waste materials can be used to improve the bearing strength of the soil and decrease in cost of construction. This paper focuses on improvement of strength and stability of lime treated expansive soil by using rice husk ash as additive. Compaction, Unconfined strength test, and California bearing ratio tests were performed on soil by adding lime in increments of 2 to 12% and then optimum lime was determined. To the optimum lime soil mix rice husk ash an agricultural waste was added in increments of 2 to 12 % and optimum RHA was determined.

Effect of salt solution on the optimum lime contents of bentonite and silt

Effect of salt solution on the optimum lime contents of bentonite and silt

Investigational study on the influence of lime and coir fiber in the stabilization of expansive soil

This research paper describes the method of expansive soil stabilization using lime and coir fibers. Coir fibers are rich in lignin content that helps them to retain their tensile strength even in wet condition. Locally available soil in and around Kuniamuthur, Coimbatore were collected for stabilization. The soil’s index properties such as specific gravity, moisture content and compaction effect were determined. The effect of penetration level, compression and shearing were experimented for plain and reinforced soil with varying fiber content such as 0%, 0.5%, 1%, 1.5% along with 5% optimum lime addition based on the previous research studies. The results shows that CBR values increases beyond the 1.5% and UCS and Shear strength attains a maximum value at 1% addition of fiber and 5% optimum level of lime. Hence 1% coco fiber content and 5% lime is concluded to be the optimum addition for an effective soil stabilization.

Blending Lime with Sugarcane Bagasse Ash for Stabilizing Expansive Clay Soils in Subgrade

Expansive soils constitute one of the most frequently encountered and challenging soils to geotechnical engineers. This study assessed the possibility of utilizing sugarcane bagasse ash (SCBA) by partially replacing slaked lime to stabilize expansive clay soils. The soil samples were picked from Muduuma area, Mpigi district, Central Uganda. Experimental tests of linear shrinkage (LS), plasticity index (PI), and California Bearing Ratio (CBR) were conducted on both unstabilized soil and SCBA-lime treated samples. The SCBA-lime mixture was prepared by partially replacing 5% lime with SCBA at 2, 4, 6, 8, and 10% by weight. Hence, SCBA was used in proportions of 0.1, 0.2, 0.3, 0.4, and 0.5% by dry weight of the soil. The addition of lime greatly lowered the PI and LS, which later increased with the addition of the SCBA. The maximum dry density was generally lowered with the addition of lime and SCBA, from 1.87 g/cm3 to 1.58%. The CBR increased with SCBA-lime addition from 12% for unstabilized soil up to 48% at 6% SCBA replacement. The optimum lime replacement was established as 6% SCBA lime replacement based on CBR criteria. At the 6% optimum, the optimum moisture content (OMC) was 1.7 Mg/m3, LS was 10%, and PI was 20%. This study demonstrated the potentiality of SCBA as a novel construction material, specifically by partially reducing the usage of the unsustainable, non-environmentally friendly lime. It is also expected to enable using currently unsuitable clays from the region.

Utjecaj vapnene prašine na ponašanje glinovitog tla

High price of land and importance of modern construction has imposed the need to strengthen weak clay soils. The stabilization of these soils has been conducted using various additives. Due to its low cost, availability, and positive impact on resistance, lime has traditionally been applied for stabilisation of poor and sensitive types of soils. In this research, lime powder, added in the percentages of 0, 2, 4, 8 and 16 of the dry soil weight, was mixed with kaolinite clay soil and its various engineering parameters were investigated during the curing time of 90 days. PH change, Atterberg Limits, optimum water content, and the modified clay maximum dry unit weight, were determined at different percentages of lime during the curing time. In the scope of determination of an optimum lime powder content, the Unconfined Compressive Strength tests (UCS) and CBR tests were conducted. The Young’s modulus was determined based on UCS testing and definition of stress-strain curve. The results showed a significant increase in the effective, responsive performance of lime in the soil and a remarkable increase in the maximum compressive strength (qu), cohesion, and Young’s modulus.

Experimental evaluation of the optimum lime content and strength development of lime-stabilized rammed earth

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