Addition Of Lime Research Articles

E. coli CB390 as an Indicator of Total Coliphages for Microbiological Assessment of Lime and Drying Bed Treated Sludge

The use of a single host strain that allows for an evaluation of the levels of total coliphages in any type of environmental sample would facilitate the detection of and reduction in complexity and costs, favoring countries or areas with technical and economic limitations. The CB390 strain is a candidate for this type of simultaneous determinations, mainly in water samples. The objective of the study was to establish the recovery capacity of the CB390 strain in solid and semi-solid samples and to evaluate the microbiological quality of the sludge generated and stabilized by lime and drying beds in two WWTPs in Colombia. The results of both matrices indicated that CB390 recovered similar numbers of total coliphages (p > 0.05) against the two host strains when evaluated separately. Only the drying bed treatment was able to reduce between 2.0 and 2.9 Log10 units for some microorganisms, while the addition of lime achieved a maximum reduction of 1.3 Log10 units for E. coli. In conclusion, the CB390 strain can be used in solid and semi-solid samples, and the treatment in a drying bed provided a product of microbiological quality. However, the results are influenced by the infrastructure of the WWTP, the treatment conditions, and the monitoring of the stabilization processes.

Valorization of SiMn Sludge for Production of Low-Phosphorus Ferroalloys

The sludge generated by wet scrubbing the off-gas from a silicomanganese plant in Norway represents a significant loss in silicon and manganese values. This work seeks to extract these values in the production of ferroalloys and slags that can be utilized by alternative industries. Carbothermic smelting the sludge together with iron or iron scraps at 1600 °C produced FeSiMn alloys consisting of 57–64 wt.% Mn, 16–22 wt.% Si and 18–25 wt.% Fe. The low level of phosphorus in the sludge allowed for beneficial phosphorus concentrations as low as 500 ppmw in the metal alloys. The addition of lime to the material mix resulted in increased evaporation of alkalis, capture of sulfur in the slags as calcium sulfides and slag compositions similar to conventional steel-making slags that can be recycled accordingly.Graphical

Efficiency of mineral additives to binding component for making hardening mixtures at underground operations

For effective operation of mining enterprises, including mines of ferrous metallurgy, supply of quality binding components is necessary to make hardening mixtures for packing of goave, aroused at underground development of hard mineral deposits. Results of the study of compositions based on ash-cement, nepheline, belit-aluminates and lime binding component made of mining and metallurgical production wastes presented. Application of vibro-, mechanical- and electrochemical activation methods to obtain filling mixtures from local low-quality raw materials, as well as activation of binding components were analyzed. A model to evaluate efficiency of binding additives presented. It was shown that decrease of cement consumption by addition of binding components of mineral origin requires perfection of mining processes, first of all, grinding and activation. It was proved, that additions of electric filters ash, nephelines, belit-aluminates and lime, obtained by utilization of current and old tailings to the basic binding component – portland cement – makes it possible to obtain hardening filling mixtures, having high enough strength to apply them at goave packing. Application of the study results makes it perspective for depressed mining and related enterprises to survive under conditions of the forming market.

Biochar amendment improves soil physico-chemical properties and alters root biomass and the soil food web in grazed pastures

Biochar application has been recognised as an effective way to improve soil functions. In this study, we investigated how adding biochar as an amendment affects soil biological and physico-chemical properties in grazed pastures in a one-year field-based mesocosm experiment conducted on two contrasting soils – a sil-andic Andosol and a dystric Cambisol. Each site had two pastures managed under different nutrient and livestock practices: with and without effluent under dairy cow grazing on the Andosol, and with either nil or high phosphorus (P) fertiliser input under sheep grazing on the Cambisol. The soil amendment treatments were: (i) willow biochar produced at 350 °C (1% w/w); (ii) lime, added at the liming equivalence of the biochar application (positive control); (iii) no amendments (negative control). With few exceptions, after 12 months and compared with initial values and controls, biochar caused (i) an increase in soil total nitrogen (N) and Olsen P content (all P < 0.005) beyond those expected from the N and P added with biochar; (ii) decrease in soil bulk density (P < 0.005), on average by 7%, more than can be explained by the reduced density of the biochar added; (iii) increase in microbial biomass C (P < 0.005), and (iv) increase in root biomass by 6.9 Mg ha−1 (P < 0.005). Lime addition increased pH values in both soils under all four management practices, and increased earthworm abundance compared with controls across all sites. In biochar-amended soils, earthworm abundance was higher only in the Andosol without effluent (P < 0.05), while Collembola abundance was significantly higher (P < 0.005) than the controls in all pastures; there was no effect on soil Oribatida and Gamasina populations. Adding biochar made from willow wood produced at low temperature to these pasture soils can positively affect the soil structure, nutrient cycling, and stimulate root growth, a key contributor to organic C input to the soil and the soil food web.

An investigation on the effect of lime addition on UCS of Indian black cotton soil

The study’s objective is to determine the optimum content of lime added to Indian black cotton soil to improve the soil’s unconfined compressive strength (UCS). The lime was added to the black cotton soil in varying proportions of 3%, 6%, 9% and 12% of the dry weight of the soil. The engineering properties of weak black cotton soil (BCS) were determined experimentally according to Indian Standard specifications. It was found that the soil under test consisted mainly of silt 75.60% and clay 18.80%. The laboratory testing showed that the value of maximum dry density (MDD) increases from 1.605 gm/cc to 1.693 gm/cc and the UCS value increased from 50.2 kN/m2 to 90.6 kN/m2 with 9% addition of lime content and for 28 days of curing time. The UCS of soil–lime mix decreased drastically beyond 9% addition of lime, showing that the optimum value of lime content to strengthen the weak soil is 9%. The strengthening of black cotton soil with the addition of lime as an additive provides stability to the civil engineering structures like sub-base/subgrade for roads and other engineering projects.

Spring deferment and N-P fertilization in natural grasslands vulnerable to summer water deficit

In Campos grasslands, the production of forage and its variability are driven by the amount of rainfall. In this context, stockpiling forage from spring to summer is a useful tool to maintain the feed supply for livestock, but so far it has not been developed due to the lack of information for farmers decision-making. In this paper we evaluated the response of pasture production to spring grazing deferment in a shallow basaltic grassland in 12 combinations of lime (0 and 1500 kg ha-1 of CaMg(CO3)2), phosphorus (0 and 90 kg ha-1 of P2O5) and nitrogen (0, 75, 150, and 300 kg ha-1 of N, except in the upper two N levels that were evaluated only with lime) addition. Forage accumulation, sward height and nitrogen nutrition index (NNI) were evaluated every 15 days during 75 days. Both sward height and available forage mass increased linearly with the deferment time. The lime application did not affect the forage accumulation rate, while the single nitrogen and phosphorus addition only showed a slight positive effect, however the combined addition of N-P fertilization tripled the forage production. Nitrogen fertilization improved the NNI and was further enhanced by the combined application of N and P. Our results suggest that the capacity of shallow basaltic grasslands to accumulate deferred forage is co-limited by N and P availability.

Development of Improved Liming Process based on Automated pH Monitoring and Control System

The control of pH of a process plays an important role in many chemical or biological reactions. The monitoring and control of pH of processes like wastewater treatment, manufacturing food and leather making facilitate to reduce pollution and improve the quality of the final product. The focus of this study is to optimize the usage of lime and recycling of spent liquor through continuous monitoring system of pH to achieve near zero residue from liming operation. But the challenges are nonlinear behaviour of the system and frequent fouling of pH sensors. The system developed monitors the pH values and controls the cycling time and the addition of lime as per the user set profile. The real time data of pH values in the process is logged on to the PC for further analysis. The efficacy of the system developed was validated at lab level and can be easily scaled up for implementation in industries. The results showed that the effluent from leather making can be minimized by adopting automated pH monitoring and control systems.

Long-term effects of imbalanced fertilization with lime and gypsum additions on denitrifying functional genes of an Ultisol at Yingtan, Jiangxi, China

The abundance of denitrifying functional genes plays a key role in driving the soil nitrous oxide (N2O) emission potential. Nitrite reductase genes (nirK and nirS) and nitrous oxide reductase genes (nosZ I and nosZ II) are the dominant denitrifying funtional genes. In this study, real-time quantitative PCR was conducted to evaluate the effects of 32-year imbalanced fertilization and lime and gypsum additions on the abundances of nirK, nirS, nosZ I and nosZ II genes in an Ultisol at Yingtan, Jiangxi Province. We further explored the underlying driving factors. The results showed that, compared with the balanced fertilization treatment, fertilization without phosphorus (P) signifi-cantly decreased the abundances of nirK, nirS, nosZ I and nosZ II genes. Fertilization without nitrogen (N) significantly reduced the abundances of nirK, nosZ I and nosZ II, but did not affect the abundance of nirS. Fertilization without potassium (K) did not affect the abundances of all denitri-fying functional genes. Results of stepwise regression analysis and random forest analysis showed that soil pH was a key environmental factor affecting the abundances of nosZ I and nosZ II. The application of lime or lime + gypsum significantly increased soil pH, which subsequently increased the abundances of nosZ II and nosZ II/nosZ I by 150%-231% and 127%-155%, respectively. Our results suggested that application of lime or lime + gypsum favored nosZ II more than nosZ I in upland Ultisols, which might enhance the relative importance of nosZ II in N2O reduction. Overall, fertilization without P would reduce denitrifying gene abundances, while the application of lime or lime + gypsum enriched nosZ II and increased ratio of nosZ II/nosZ I, which might be beneficial for reducing N2O emission potential in the Ultisols.

Influence of lime (CaO) on low temperature leaching of some types of bauxite from Guinea

Abstract In Bayer process, low temperature treatment of bauxite generally applicable to gibbsite in the presence of a significant amount of boehmite (&gt;3%), requires a temperature increase and the addition of an additive to improve the leaching conditions. This research is based on improvement of low temperature leaching conditions 108 °C and the addition of lime during the attack of some types of bauxite in Guinea. TRUhat is Low Mono Grade Bauxite (LMG), Standard Metal Grade (SMG) and Fria Bauxite (BF). The results of this study confirm an improvement in the extraction yields. Additionally, it shows an increase in yields of two points when the lime dosage is low, and between 0.5 and 3% of the bauxite weight. Based on the mineralogical and chemical composition findings, minerals contain of SMG bauxites are difficult to decompose while BF bauxites are easy to process. Sougueta limestone was used for testing. After calcination, we obtained CaO added at a rate of: 0.3; 0.5; 1; 3 and 6% of the bauxite weight to finally obtain the highest leaching efficiency compared to the leaching efficiency of bauxite without addition. The best leaching rate obtained for LMG, SMG and BF are respectively: 89.01, 87.15 and 89.74% for additions of 1, 0.5 and 3% CaO respectively.

Investigation of Acoustic Properties of Poroelastic Asphalt Mixtures in Laboratory and Field Conditions.

Measures for the improvement of acoustic conditions in the vicinity of roads include the construction of pavement structures with low-noise surfaces with optimal macrotexture and the highest possible sound absorption coefficient. Laboratory evaluation of acoustic properties of a designed asphalt mixture before its placement in the pavement is a good solution. Currently, the most popular method for the determination of the sound absorption coefficient of various construction materials under laboratory conditions is the Kundt’s tube test. Sound absorption coefficient can also be assessed based on field and laboratory measurements performed using a Spectronics ACUPAVE System. Other parameters characterising the acoustic properties of road pavement courses include air void content and water drainability or permeability. The article presents an analysis of results of sound absorption coefficient obtained using a Spectronics ACUPAVE System and water drainability and permeability of poroelastic mixtures obtained both in laboratory and on test sections, in relation to air void content and grading of the mixtures. It was established that poroelastic mixtures containing an aggregate of maximum particle size of 5 mm are characterised by better acoustic properties than mixtures with a maximum aggregate particle size of 8 mm. Changes of crumb rubber aggregate grading and bitumen type (within the tested range of values) as well as the addition of lime have shown no evident influence on the sound absorption coefficient. Noise level values at the speed of 30 km/h according to the CPX method were measured as well. Relationships between sound absorption coefficient, water drainability/permeability, and air void content were determined. The performed analyses confirmed that Spectronics ACUPAVE System may be applied for evaluation of acoustic properties of asphalt mixtures in laboratory conditions, but further research is needed to reduce the uncertainty of the results.

Simultaneous reductions in antibiotics and heavy metal pollution during manure composting

The co-existence of antibiotics and heavy metal (HM) is common in manure. However, existing strategies for improving antibiotic dissipation or HM immobilization during composting rarely consider their combined pollution. In this study, we used agricultural lime and a newly designed attapulgite-activated carbon composite (AACC) to enhance the stabilization of HMs in a pilot-scale swine manure composting system and assessed the effectiveness of these materials for removing antibiotic residues. Results indicated that the application of either lime or AACC simultaneously enhanced HM immobilization and antibiotic degradation. In particular, the addition of AACC reduced the enrichment of Cr, Cd, Pb, and As during composting and decreased the half-lives of the antibiotics from 10.7 days to 6.3 days, which were more effectively than lime. The physicochemical and microbiological responses to different additives were subsequently studied to understand the mechanisms underlying the fates of HMs and antibiotics. High HM stress in manure inhibited antibiotic dissipation, but metal immobilization alleviated this effect. The AACC accelerated HM immobilization by surface adsorption and metal precipitation, and this enhancement strengthened during the late composting stage due to an increase in pH, whereas lime exhibited a short-term effect. Moreover, the AACC addition enhanced the contribution of bacteria to changes in antibiotic concentrations, while the increase in pile temperature could be a major factor that contributed to the acceleration of antibiotic degradation after the addition of lime. Characterization of the final compost further showed that AACC-treated compost had the lowest residual concentrations of HMs and antibiotics, higher mortality of ascarid egg, improved nitrogen conversation, and reduced phytotoxicity. Thus, co-composting of swine manure with AACC is a promising approach for producing safer compost for use in agriculture.

Laterite as a base and subbase material for flexible pavement – a review

Rapid economic growth is leading to ubiquitous expansion in highway projects around the world. Utilization of natural aggregate resources for the construction of flexible pavement has led to uncontrollable quarrying in the state of Kerala. The recent landslides in Kerala which took the lives of many people is the aftermath of extensive quarrying activities. Utilization of treated native soil in the structural layers (Subbase and base) of flexible pavement can widely avert the danger associated with ecological imbalance due to quarrying. The main objective of this review article is to enlighten the researchers and practicing engineers about the key advances developed in the last 10 years for utilizing native laterite soil in the base and subbase layers of flexible pavement. On the basis of various researches, laterite soil treated with lime, cement and other additives showed considerable enhancement in the compaction characteristics, unconfined compressive strength (UCS) and California Bearing Ratio (CBR). As stipulated by MORTH (Ministry of Road Transport and Highways), for a layer to be suitable as a subbase material in flexible pavement, minimum CBR value must be 30%. From the extensive review, it was found that the treated laterite soil satisfied the MORTH criteria for use as a subbase layer in flexible pavement.&#x0D; Keywords- Ferrocement, cyclic loading, flexural behavior, precast ferrocement wall, dynamic analysis, static analysis

An experimental investigation on strength characteristics of fiber-reinforced clayey soil treated with lime or cement

This paper presents an experimental investigation on the strength properties of fiber-reinforced clayey soil stabilized with lime or cement at lower content (5% by weight) cured for 28 days. A series of consolidated undrained (CU) triaxial compression tests and unconfined compressive (UC) strength tests were conducted on compacted untreated, lime-treated and cement-treated clayey soil specimens reinforced with different polyester fiber content (i.e., 0%, 0.05%, 0.1%, 0.2% by weight) to evaluate the effect of fiber content on the strength behavior of tested soil. Test results indicated that the addition of lime or cement gave a significant increase in strength and strength parameters at a certain fiber content, where the improvement effect of cement is better than that of lime. Strain-softening curves were obtained for lime-treated or cement-treated fiber-reinforced specimens compared with the strain-hardening for fiber-reinforced ones. The residual strength is about 75% on average the peak strength for fiber and lime-treated specimens compared to about 50% decrease of peak strength for fiber and cement-treated specimens. The stress and strain curve for the specimen with higher fiber content lies above on that with lower fiber content. Fiber-reinforced plain soil showed a ductile failure mode compared with brittle failure mode for lime or cement-treated specimen. The values of undrained shear strength, unconfined compressive strength, cohesion and internal friction angle of plain soil and lime-treated soil followed the same increase trend when the polyester fiber content increased from 0% to 0.2%. While for lime-treated soil specimens, peak values can be observed when the fiber content was 0.1%. It is recommended to use the optimum fiber content to achieve a better improvement effect in the engineering applications.

Soil Behavior and Characterization: Effect of Improvement in CBR Characteristics of Soil Subgrade on Design of Bituminous Pavements

The California bearing ratio (CBR) value greatly influences the strength characteristics of soil subgrade, hence, is an important parameter to understand the soil behavior pertinent to pavement design. The CBR value, along with the empirical curves, is used to determine the thickness of a pavement and its component layers, thus aiding in the design of flexible pavements. If the naturally occurring local soil subgrade has low strength in terms of CBR and poor engineering properties, improved soil subgrade has to be provided by way of lime/cement treatment or by mixing locally available cheap alternative materials or by mechanical stabilization and other similar techniques. In the present study, an attempt has been made to review the soil behavior in terms of CBR characteristics for two methods of soil properties enhancement, viz. addition of lime and rice husk ash to soil and the method of improvement of soil subgrade overlain by compacted fly ash with geotextile at soil–fly ash interface. Using the data obtained from the review study, design of a bituminous pavement with granular base and sub-base layers and an alternative pavement with RAP layer with CTSB sub-base have also been attempted using the IRC 37:2018 guidelines and IITPAVE software to find out the adequacy of the two subgrade improvement methods with respect to reduction in pavement thicknesses. Further, some design charts have also been developed for the stabilized soil subgrades for traffic intensities of 5, 15, 30, 50, 80 and 100 msa for both pavement types.

Impact of influent deviations on polymer coagulant dose in warm lime softening of synthetic SAGD produced water

Warm lime softening is commonly used to reduce hardness, silica, and a small fraction of organic matter from steam-assisted gravity drainage (SAGD) produced water through the addition of lime, soda ash, MgO, coagulant and flocculant. We report a systematic study on the impact of solution chemistry on the epichlorohydrin-dimethylamine coagulant demand for the treatment of synthetic SAGD produced water. Concentrations of magnesium, calcium, sodium bicarbonate, clay (mimicking suspended solids), sodium metasilicate (representing silica), and humic acid (mimicking dissolved organic matter) were varied to study their impact on coagulant demand. The impact of the concentration of lime, soda ash, and MgO on coagulant demand was also studied. Within the studied concentration range, the coagulant dose increased linearly with increasing concentration of humic acid (Ycoagulant = 29 + 0.703XHA) and silica (Ycoagulant = 52 + 0.537Xsilica), and increased slightly with increasing concentration of lime and soda ash, but remained almost unchanged with increasing concentration of dissolved hardness, clay, or MgO. The observations were correlated to the understanding of the electrokinetic properties of CaCO3 and Mg(OH)2 particles in lime softening. The findings provide insights for evaluating onsite coagulant dose and optimizing the process.

Study of lime addition to sewer sedimentation soil to improve the soil properties for use as construction materials

Sewer sedimentation in general cannot be used directly as construction materials due to the behaviour which is hard when it is dry and weak and soft when it is wet. Several engineering treatments that can be taken to improve the soil properties including adding a chemical stabilization using a mixture of materials. The stabilized soil samples came from Lam Glumpang Village, Ulee Kareng District, Banda Aceh. The purpose of this study was to obtain mechanical soil parameters before and after stabilization with lime. This research was conducted by mixing lime and lime soil with variations of 2%, 4%, 6%, and 8% of the dry weight of the soil. According to the AASHTO classification system, the soil is classified as A-4 (8) soil type, namely moderate to poor silt soil with an index group of 8, and according to the USCS classification system it is classified as an inorganic silt soil type with the symbol ML, namely silt soil with low plasticity. The results showed some good improvement in soil properties. In general, the addition of lime which has a good effect on sewer sedimentation soil in the mixture proportion of 6%.

Liming and priming: the long-term impact of pH amelioration on mineralisation may negate carbon sequestration gains.

Acidity negatively impacts upon soil capability and conditions across approximately 50% of the world's arable land. Plant growth and nutrient cycling are known to respond positively to the addition of lime to decrease soil acidity. However, the interactions between liming and soil carbon dynamics remain incompletely understood. The nexus of soils, food security and climate change make this topic an urgent concern for investigation. This study utilised soils (Cambisols) from three long-term lime field trials (13-39 years) on farms. Soils (0-10 cm) were incubated in the laboratory for 3 months with and without 13C-labelled wheat crop residue. This approach enabled direct quantification of the CO2-C originating from three different processes; decomposition of extant soil organic carbon (SOC), decomposition of the added crop residue, and SOC priming i.e. the additional decomposition of SOC stimulated by addition of plant material. Biological and chemical soil properties were also quantified, with a novel application of measurement of the abundance of the functional genes involved in SOC decomposition. Priming was significantly increased in limed soils (P<0.01). The abundance of both archaeal rRNA genes, and the laccase-like functional gene involved in lignin decomposition correlated significantly and positively with SOC priming (Rho 0.46, P<0.01). Decomposition of extant SOC was positively correlated with pH and N (Rho 0.65, P<0.001). Decomposition of the added crop residue was also correlated with pH and inorganic N, albeit less strongly than for SOC (Rho 0.43, P< 0.05). These results support the theory that the application of lime to ameliorate soil acidity improves conditions for soil microorganisms as well as for plants. Archaea, and organisms harbouring SOC-decomposing laccases, would appear to play a key role in releasing nutrients stored in extant SOC, when priming is prompted by the addition of new plant material. This work highlights the importance of taking account of multiple response factors when assessing potential solutions within the food security-climate change nexus.

Studi Pengaruh Abu Batu Bata terhadap SifatFisik dan Mekanik Lempung Terstabilisasi Kapur dari Kecamatan Tenayan Raya

Tenayan Raya Subdistrict is an area that has a thickness of soft clay layer. Some cases of building failure were cracks and tilts due to high shrinkage of soil. Nearby is also a brick home industry center, where ashes are produced from bricks burning. Soil Improvement of Tenayan-Raya's Clay and utilization of brick ash will be carried out in this research. This study aims to stabilize the soil with lime and utilize the brick ash to improve shear strength and bearing capacity of the soil. The study was conducted in the laboratory by making several combinations of content clay, lime, and Brick Ash (BA), for the soil mixture which will be added with 10% ash brick. The effect of curing and soaked will also be seen for its rising on soil properties of Unconfined Compression Strength, and CBR laboratories. The influence of water will also be reviewed on the dry side, optimal moisture content, and wet side. The test results show that the Soil has Low Plasticity soil type category CL-ML symbols, according to the Unified classification. Increasing of strength due to stabilization with lime is obtained in conditions of water in optimal moisture content, where the addition of lime is 10% and 10% brick ash, was produced to increase the maximum value of Unconfined Compression Strength and CBR laboratory value. Curing setup time and saturation (soaked) also had affect the value of Unconfined Compressive Strength and CBR laboratory test. At longer time for curing, shear strength will rise proved by the value of UCS Test andbearing capacity value also increase that can be seen of the laboratory CBR test. Curing will make the shrinkage of clay reduced, this can be proven from differences value of Unconfined Compressive strength test between samples with and without soaked, are relatively small.

Experimental Studies and its Application using PLAXIS-2D for Lithomargic Clay Stabilized by GBFS and Lime

Lithomargic clay is found along the Eastern and Western coasts of Southern India. Presence of weak soils like lithomargic clay below the foundations, cause serious problems when they come in contact with water, and non-availability of stronger fill materials locally, to replace them is a challenge to foundation engineers. An attempt has been made in this paper to improve the strength of lithomargic clay by chemical stabilization using Lime and Granulated Blast Furnace Slag (GBFS). Disposal of massive amounts of industrial waste, GBFS, has become an environmental problem and utilization of the same for soil stabilization would be a sustainable solution for disposal. To optimize the use of lime and understand the mechanism behind the gain in strength, laboratory experiments were conducted on lithomargic clay, by replacing it with varying amounts of GBFS and addition of different percentages of lime. The optimum lime and GBFS content were found to be 4% and 20% respectively. Further optimization was done by mixing lithomargic clay with 4% lime and 20% GBFS and a significant strength improvement was observed. SEM and XRD analyses were conducted on the stabilized soil and the increase in strength was established from structural changes and formation of compounds like CSH and CASH. PLAXIS 2D was used to understand the settlement behavior of both the unstabilized and stabilized soils below strip foundations of varying widths. From load settlement analysis, it was observed that the net allowable pressure increases with increase in GBFS content and further increases with addition of lime to soil stabilised with optimum GBFS.

Improvement of shear strength and compressibility of soft clay stabilized with lime columns

Soft clay improvement using lime columns is an effective and economic method; which used mainly for enhancing the engineering properties of soft soil, reducing settlement and increasing shear strength. Improvements in engineering properties of soft clay can be achieved instantaneously with small additions of lime to soft soils. However, the effectiveness of this improvement depends on the quantity and type of lime as well as the mineralogical composition of soil. In this paper, the behavior of soft clay improved with lime columns has been studied. A series of large scale direct shear box tests were carried out with different number of lime columns, diameter, and different curing periods. Experimental study was carried out on both single and a group of lime columns. The results showed that the group of columns increased the shear resistance of soft clay soil with lesser horizontal deformation. Shear strain decreased by 28% and 47% in case of using 1 and 4 lime columns respectively after 7 days curing. Meanwhile, increasing the lime column diameter was found to increase the shear strength of soft clay and improve its compressibility. Finally, the shear strength was found to be increased by 53% when using a single lime column, while when using a group of 4 lime columns with diameter/length (D/L) ratio equals 0.28, the shear resistance is duplicated compared to the case of soft clay without lime columns.