Lime Incorporation Research Articles

Integration of carbide lime substrate for enhanced energy recovery and dye decomposition in plant-microbial fuel cell coupled with cupric oxide/carbon cathode

In this study, an innovative and efficient carbide lime-assisted plant-microbial fuel cell (Ca-P-MFC) system was developed for treating dyestuff effluent and generating electricity. This system featured a carbon brush anode and a cupric oxide/carbon (CuO/C) cathode. The Ca-P-MFC system revealed outstanding performance compared to both the P-MFC and CW systems. At a carbide lime loading of 200 mg L−1, the Ca-P-MFC system achieved an impressive methylene blue decomposition efficiency of 86.6% and a maximum power density (P) of 60.2 mW m−2. The improved performance can be attributed to the incorporation of carbide lime, which promoted microbial reactions extending from the electrode surfaces throughout the operational area of the system. Furthermore, carbide lime served as an effective electron carrier, facilitating electron transfer across the system. The optimal loading of carbide lime was systematically evaluated in the developed Ca-P-MFC system, providing comprehensive insights into the mechanism of P-MFC.

Microestrutura e propriedades mecânicas de geopolímeros com diferentes teores de cal dolomítica

Abstract This study investigated the effect of dolomitic lime incorporation on the microstructure and mechanical properties of metakaolin-based geopolymers activated by alkaline solution. Five geopolymer mixtures were prepared with the addition of 0.0%, 2.5%, 5.0%, 7.5%, and 10.0% dolomitic lime. The microstructure of the geopolymers was evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction analyses (XRD). The compressive strength of the mixtures ranged between 53.2 and 63.0 MPa after 28 days of ambient curing. SEM/EDS analyses showed that the main phases formed were the N-A-S-H gel together with the C-A-S-H and N-M-A-S-H gels in the mixtures with dolomitic lime. In summary, the results showed that the incorporation of dolomitic lime can significantly improve the microstructure and properties of geopolymers.

Biometric Parameters and Yield Components of Wheat (Triticum aestivum) as a Function of Lime and Phosphogypsum Reapplication

ABSTRACT The effects of lime and phosphogypsum (GY) on wheat (Triticum aestivum) nutrition are well documented. However, little is known about the influence of these soil amendments on biometric parameters or yield components. This study investigated the effects of lime and GY on wheat crops grown at cation base saturation (BS) levels of 44%, 70%, and 90%, achieved by surface application or soil incorporation of lime. Two additional treatments were included: surface liming to 70% combined with a standard rate of GY (3.71 Mg ha−1) or twice the recommended GY rate (7.42 Mg ha−1). The experiment was conducted during two crop seasons in Southern Brazil. The treatments did not influence dry biomass partitioning between spikes, stems, and leaves and total. In one season, liming increased flag leaf area, which was strongly associated with grain yield. Regardless of the rate, application method, and combined use of GY, liming increased the number of grains per spike in both seasons, which was the variable that most influenced wheat yield. Liming also increased spike length and the number of spikelets per spike in the 2018 season. No benefits were seen when lime was applied by soil incorporation, BS was raised to 90%, or liming was combined with GY application. The results showed a positive effect of liming on wheat yield components that are associated with grain yield.

Evaluation of the incorporation of artisanal lime into the composition of stabilized earth blocks

This study evaluates the incorporation of artisanal lime into the composition of Stabilized Earth Blocks (SEB) to enhance local materials and minimize the use of cement. The objective is to develop a sustainable approach that utilizes available resources while meeting construction needs. The physico-mechanical behavior of the SEB was examined through a mixed chemical stabilization method (cement/lime), gradually replacing cement with artisanal lime. The main parameters analyzed include the replacement rate and the nature of the stabilizer, allowing for an in-depth understanding of the effects of this integration. The results indicate that replacing 12.5% of the cement with artisanal lime improves the long-term physico-mechanical properties of the SEB, particularly in terms of density, absorption, porosity, as well as compressive and flexural strength. Furthermore, this approach supports the transition towards more environmentally friendly construction practices. Additionally, the study includes a comparison of the results obtained using industrial lime, thus reinforcing the relevance of using lime in construction.

Incorporation of undissolved lime from previous applications can ameliorate subsoil acidity promptly and improve crop performance on sandy soils of the semi-arid regions of Western Australia

Abstract Background and aims Repeated surface application of lime for managing subsoil acidity is slow and ineffective, resulting in an accumulation of undissolved lime (carbonate) in the topsoil. We investigated the impact of the incorporation of undissolved lime into the subsoil to improve acidity and crop performance. Methods The undissolved lime in 2-cm layers of topsoil (0–10 cm) from three long-term experiments in Western Australia was measured. Both limed and unlimed topsoil with the acidic subsoil of the same profile was incubated at eight incorporation rates for six weeks, followed by growing barley and wheat in the incubated soil for two weeks to assess the impact on soil acidity and crop root architecture, respectively. Furthermore, a three-year-long field experiment was conducted following strategic tillage in limed and control plots to assess the impact on soil acidity and performance of wheat, canola and barley. Results A significant amount of undissolved lime was concentrated in the topsoil, amounting to 1.7, 1.8 and 1.3 t/ha for the limed plots at Wongan Hills, Northam and Merredin, respectively. Incubation of 5–25% topsoil after incorporation with the acidic subsoil was enough to ameliorate subsoil acidity and to improve root length density by up to 13-fold depending on undissolved lime content in topsoils and soil type. In the field experiment, the incorporation of undissolved lime also significantly improved subsoil acidity and canola performance. Conclusion We concluded that the incorporation of topsoil containing sufficient undissolved lime with acidic subsoil may offer a quick amelioration of subsoil acidity.

Impact of antiaging additives on the conventional properties of bituminous binder

Aging of binders is a complex phenomenon which reduces the longevity of flexible pavements. Aging involves change in physical, chemical, and morphological properties of binder which makes the binder brittle and highly susceptible to fatigue and thermal cracking. Antiaging additives enhance the service life of flexible pavements by reducing the impact of aging on the performance of binders. An iterative approach is essential to identify the optimal dosage of antiaging additive necessary to counteract the aging effects on binder. The present study aims to evaluate the mixing conditions for uniform dispersion of carbon black and hydrated lime within the binder matrix and thereby evaluate the impact of incorporating these antiaging additives on the conventional properties of binder. For this purpose, varying proportions of carbon black and hydrated lime are added to VG 30 binder and is subjected to softening point, ductility, and penetration tests. The optimal dosage of carbon black and hydrated lime is found to be 6 and 12% respectively based on their significant effects on the conventional properties of the binder. An optimal mixing duration of 60 and 75 min ensures uniform dispersion of carbon black and hydrated lime within the binder matrix at a mixing temperature of 120 °C and a speed of 1000 rpm thereby producing a homogenous binder mastic. Incorporation of antiaging additives up to the optimal dosage enhances the softening point whereas decreases the penetration and ductility of binder. The increase in softening point of binder with incorporation of carbon black and hydrated lime signifies enhanced resistance to rutting and permanent deformation of binder, whereas the reduction in ductility and penetration of binder with incorporation of carbon black and hydrated lime signifies the reduced susceptibility of binder to environmental factors such as temperature fluctuations, UV radiation, and oxidation. The surface texture of the additive influences the ability of binder adsorption, which subsequently affects the rheological properties of binder mastics. Significant improvement in conventional properties of binder with incorporation of carbon black and hydrated lime paves a viable and cost-effective solution for engineering application as it has a subsequent effect on the rheological properties of binder.

Optimization of hydrothermal autoclaving parameters for the synthesis of porous ceramics from porcelain tile polishing residue

Porous ceramics were synthesized using porcelain tile polishing residue (PTPR) and slaked lime (Ca(OH)2) as a reinforcing agent through a hydrothermal autoclaving method. The process parameters, including the quantity of slaked lime added, the hydrothermal autoclaving temperature, and the reaction duration, were optimized meticulously. The composition, structure, thermal and physical properties of the samples were thoroughly analyzed via Brunauer–Emmett–Teller (BET) measurements, powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The results indicated that the incorporation of slaked lime and hydrothermal autoclaving led to the formation of calcium silicate hydrate, which corresponded with an enhancement in the strength of the sample. Notably, when the quantity of slaked lime added was optimized at 30 wt%, the formation of tobermorite (5CaO·6SiO2·5H2O) was detected. At a hydrothermal autoclaving temperature of 150 °C, the formation of only sheet-like calcium silicate hydrate was observed. In contrast, at an elevated temperature of 180 °C and 210 °C, needle-like tobermorite was successfully synthesized. The porous ceramic with the most favorable structure was obtained through autoclaving at 180 °C for 10 h with 30 wt% slaked lime, exhibiting a total pore volume of 0.11 mL/g, a specific surface area of 26.35 m2/g, and a mesoporous volume fraction of 90.40%.

Evaluating the Geotechnical Properties of Stabilized Problematic Soil by Utilizing Reed Ash and Lime Mixture

Stabilization of problematic soil poses a significant challenge in civil engineering projects, especially in regions with prevalent soft clay soils. This study was carried out to study the impact of using a blend of reed ash and lime on improving and stabilizing problematic soil. A sample of soil was obtained from a location in the south of Iraq, specifically in Al-Muthanna Governorate. The treatment involved adding different proportions of reed ash (3%, 5%, 7%, and 9.0% of the soil's dry weight) along with 5% lime, which was determined as the optimal percentage based on previous research. Various laboratory tests were conducted to assess the characteristics of the treated soil, including compaction and unconfined compressive strength (UCS). The findings indicated a notable enhancement in UCS and the maximum dry density (MDD). It was observed that UCS and MDD increased with increasing the reed ash and lime mixture proportion, reaching an optimal level. Beyond this percentage, the strength started to decline. It was found that the incorporation of lime and reed ash (5% lime and 7% reed ash) into the treated soil significantly improved its strength, up to about 10 times compared to untreated soil after 28 days of curing. This approach offers additional benefits, such as reducing environmental pollution by decreasing CO2 emissions during phases of production and providing cost savings because of the affordability of the materials used.

Carbide lime as substrates to boost energy recuperation and dyestuff removal in constructed wetland-microbial fuel cell integrated with copper oxide/carbon cloth cathode.

Methylene blue (MB) was regarded as a highly toxic and hazardous substance owing to its irreparable hazard and deplorable damage on the ecosystem and the human body. The treatment of this colorant wastewater appeared to be one of the towering challenges in wastewater treatment. In this study, a microbial fuel cell coupled with constructed wetland (CW-MFC) with effective MB elimination and its energy recuperation concurrently based on the incorporation of carbide lime as a substrate in a new copper oxide-loaded on carbon cloth (CuO/CC) cathode system was studied. The crucial influencing parameters were also delved, and the MB degradation and chemical oxygen demand (COD) removal efficiencies were correspondingly incremented by 97.3% and 89.1% with maximum power output up to 74.1 mW m-2 at optimal conditions (0.2 g L-1 carbide lime loading and 500 Ω external resistance). The carbide lime with high calcium ion content was greatly conducive for the enrichment of critical microorganism and metabolic activities. The relative abundances of functional bacteria including Proteobacteria and Actinobacteriota were vividly increased. Moreover, the impressive results obtained in printed ink wastewater treatment with a COD removal efficiency of 81.3% and a maximum power density of 58.2 mW m-2, which showcased the potential application of CW-MFC.

Strategies to alleviate pH stratification and subsurface acidity in a no‐tillage system

AbstractSome no‐tillage systems necessitate amelioration of subsurface acidity. A 2‐year field trial was conducted on a no‐tillage sandy loam Cambisol, with a pH(KCl) of 4.20 in the 10‐ to 30‐cm depth. The aim was to evaluate one‐time tillage, calcitic lime forms, and lime plus gypsum combinations on soil chemical parameters, and wheat (Triticum aestivum L.) and canola (Brassica napus) production. Incorporation of lime (1.67 Mg ha−1) through one‐time chisel plowing increased soil pH(KCl) and soil exchangeable calcium in the 20‐ to 30‐cm depth by 9.1% and 210.1%, respectively, after 18 months. Conventional one‐time tillage treatments resulted in 15.0%–18.1% reduced wheat seedling establishment in the subsequent season. Surface‐applied hydrated lime (1.56 Mg ha−1) and microfine pelletized lime (1.75 Mg ha−1) both caused over‐liming (pH(KCl) > 6.5) effects in the 0‐ to 5‐cm depth after 6 months, which attenuated from 12 to 18 months. Surface‐applied lime (1.67 Mg ha−1) showed a 2.9% and 5.6% pH(KCl) reduction in the 10‐ to 20‐cm and 20‐ to 30‐cm depths, respectively, after 18 months. While combined surface application of lime (0.55 Mg ha−1) plus gypsum (1.25 Mg ha−1) showed a 3.7% and 0.5% pH(KCl) reduction in the 10‐ to 20‐cm and 20‐ to 30‐cm depths, respectively, after 18 months. Wheat (year 1) and canola (year 2) yield and seed quality parameters were unaffected (p > 0.05) by the treatments. Subsurface acidity amelioration in no‐tillage systems is best achieved through chisel lime incorporation or combined surface application of lime plus gypsum on moderately or highly weathered soils.

Mechanical properties and micro-mechanism of improved shield tunnel muck with phosphogypsum and lime

Massive shield tunnel muck is being landfilled without effective use due to high moisture contents and poor engineering properties, which not only leads to soil resources waste, but also occupies a large amounts of land sources. In this study, industrial waste phosphogypsum (PG) was recycled to improve the tunnel muck with lime, and the improved muck is aiming to be used in subgrade filling. A series of laboratory tests, including compaction tests, unconfined compressive strength (UCS) tests, california bearing ratio (CBR) tests, resilient modulus tests and microscopic tests were carried out. The effects of PG, lime, carboxymethyl cellulose (CMC) and moisture contents on physical, mechanical and microscopic properties of improved muck were examined, respectively. Results indicate that the incorporation of lime and PG significantly improves the mechanical properties and water stability of shield tunnel muck generated in silt stratum. The performance of improved tunnel muck meets the requirement for subgrade filling. Notably, for a fixed total contents of lime and PG, the proportion of 3:1 lime/PG results in the best mechanical properties and water stability. The tunnel muck generated in silt stratum mainly consists of lamellar and layered structures, which contributes to stronger cohesion among soil particles and the hydration products. The CMC has the ability to create cementation bonds among soil particles and the hydration products of lime and PG, resulting in a denser gel network microstructure.

Shallow Incorporation of Lime and Gypsum has Limited Benefit over the Sole-surface Application of Lime for Improving Grain Yield and Water Use Efficiency in the Low Rainfall Region of Western Australia

Soil acidity is one of the major soil constraints for the grain-growing industry in Australia and around the globe. While surface liming is widely adopted, it has been proven ineffective for the timely amelioration of subsoil acidity. There is a growing interest in finding alternative approaches for the effective amelioration of subsoil acidity, especially for low-rainfall regions. In a controlled environment and a field experiment, we examined whether the combined application of lime and gypsum would be more effective than lime alone under no-till (NT) and shallow strategic tillage (ST) systems for reducing the impact of soil acidity and increasing grain yield. 
 
 The controlled environment experiment highlighted that lime increased soil pH and decreased the soil exchangeable aluminium concentration (EAC) which resulted in significantly better root growth. In the field experiment, we found that the lime plus gypsum treatment, in most cases, did not significantly affect grain yield, water use efficiency (WUE) or grain quality compared to the lime treatment alone. Lime incorporation with a shallow ST was more effective in increasing soil pH and decreasing EAC at 10–20 cm depth, compared to the surface application of lime without tillage. However, ST did not affect the grain yield and WUE of wheat in 2017 and 2018 and significantly decreased the grain yield and WUE of canola in 2019 and barley in 2020. We found that measurements of either soil pH or EAC were equivalent in their ability to explain and predict the root growth of major grain crops. The results indicate that soil pH is the simplest indicator for grain growers to measure the improvement of soil acidity with liming and its impact on root growth and crop productivity. We recommend the application of lime as the preferred amendment on acidic sands, while shallow ST should be avoided in the low rainfall region. Further studies involving deep ST are warranted.

Mineralogical study of a binder based on alkali-activated coal gangue

The activation of materials, including those derived from mining waste, has garnered growing interest among researchers and industrialists seeking to produce eco-friendly binders. Activation can be achieved through various methods, with mechanical grinding and chemical alkaline activation using substances like NaOH being the most commonly employed. This study specifically investigates the properties of alkali-activated coal gangue-lime (AACG-L) using techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM-EDS). Lime (CaO) is acknowledged as an effective cementing agent that enhances the reactivity of raw coal gangue. The synthesis of AACG-L involves two successive stages: grinding and reducing grain size with 5% lime incorporation, followed by activation using 5 M NaOH and subsequent 28-day curing. XRD, FTIR, and SEM-EDS analyses confirm that the resulting AACG-L product primarily comprises hydrated calcium aluminate silicate (C-A-S-H), hydrated alkaline aluminate silicate (N-A-S-H), and portlandite Ca(OH)2.

Measurement of lime movement and dissolution in acidic soils using mid-infrared spectroscopy

Acidification of surface and sub-surface soils limits agricultural production globally. Conventional surface application of lime is the most common amelioration approach for surface acidity. However, amelioration of sub-surface acidity is challenging to achieve using this approach. Testing the efficacy of liming to treat acidity through the soil profile via the measurement of lime movement requires high throughput information about soil properties at a high spatial resolution, which can be time consuming and expensive using traditional laboratory analysis. Here, we investigated the potential of Mid Infrared (MIR) spectroscopy as a tool to monitor lime dissolution and vertical movement through soils at high spatial resolution. Soil samples were collected at 2.5 cm intervals to 20 cm depth at three trial sites in South Australia, with various lime treatments applied either 6 years or 1 year prior to sampling. MIR Partial least squares regression (PLSR) predictions were undertaken to measure lime dissolution and alkalinity movement via soil pH, and undissolved lime presence via soil carbonate concentrations. Lime balance calculations were then performed to determine the fate of applied lime and assess efficacy of various rates of lime products applied at the surface only or via incorporation. MIR-PLSR prediction model performance was strong for both soil pH (R2 = 0.923 and RMSE = 0.202) and carbonate (R2 =0.829 and RMSE=0.042 CO3%). Results indicated the movement of alkalinity at all sites was limited, and revealed increased movement at the longer-term (∼6 years) vs shorter-term (∼1 year) sites where lime was surface applied. Lime balance calculations indicated that residual lime remained in the top 7.5 cm of the soil profile while soils remained acidic below this depth. Findings suggest that incorporation of residual lime and additional lime applications may be necessary to remediate sub-surface acidity. A decision tree was developed to inform management of surface and sub-surface soil acidity. The study validates the potential of MIR spectroscopy to measure and monitor the effectiveness and movement of lime with improved resolution in acidic soils.

Hydration, carbonation and strength development of reactive MgO cement blended with lime (CaO) under different curing conditions

This paper investigated the effect of lime added as substitution (by up to 30 wt%) of magnesia on the performance, phase composition and CO2 sequestration capacity of blended reactive MgO cement (RMC) under two different curing conditions. A relationship between the strength development and formation of hydration and carbonation phases was also established. The results showed that the incorporation of lime promote the setting and initial heat generation of RMC. More lime replacement led to higher CO2 absorption capability under both ambient and accelerated carbonation conditions, mainly due to the improved calcite. The presence of uncarbonated portlandite was found to have negative impact on strength development of blended RMC before and after water exposure. Carbonation curing enhanced the conversion of portlandite and brucite into calcite and nesquehonite, respectively, which effectively reduced the porosity and improved the denseness of blended RMC. The improvements in carbonates content, morphologies and microstructure in samples containing 20% lime resulted in ∼30% higher 28-day compressive strength than the plain samples.

Experimental Study on the Mechanical Properties of Xinyang Red Clay Improved by Lime and Fly Ash

There is limited research on the utilization of lime and fly ash for improving the mechanical properties of red clay soils. This study investigates the physical and mechanical properties of modified red clay with single fly ash, single lime, and mixed cases using various experimental tests, such as direct shear tests, unconfined compression tests, etc. Scanning electron microscopy was also used to analyze the microstructure of the modified red clay. The findings indicate that the incorporation of lime and fly ash resulted in a decrease in the liquid limit, plasticity index, and maximum dry density of the modified soils, while increasing the plastic limit and optimum water content. The enhancement of lateritic soils by lime and fly ash was primarily attributed to the generation of gel substances from the active ingredients, which improved the soil microstructure and increased its strength. The case study in this paper provides a new perspective on soil improvement.

Soil phosphorus forms and fertilizer use efficiency are affected by tillage and soil acidity management

Liming combined with no-tillage (NT) can increase the efficiency of P use by accumulating soil P in more available forms and improving root exploration due to the absence of toxic Al3+. This study aimed to evaluate the long-term effect of different combinations of soil tillage managements and liming in a subtropical Oxisol on the accumulation of P forms, legacy P index, and P use efficiency. A long-term experiment was used, established in 1987 testing (i) conventional tillage with lime (lime-CT) and control (control-CT), (ii) NT with lime (lime-NT) and control (control-NT), and (iii) occasional tillage with lime (lime-OT). The NPK fertilization was the same for all treatments. The accumulated grain yield and P use efficiency of 56 crops between 1987 and 2019 were evaluated. In 2019, soil samples were collected in the 0–5, 5–10, and 10–20 cm layers and submitted to a sequential chemical fractionation of P, P indexes, and soil acidity parameters. The results reveal that is necessary to correct acidity to increase crop yields and P use efficiency, regardless of the soil management used. This increase is enhanced when soil acidity correction by liming is combined with the use of conservation systems such as NT. Furthermore, after liming with incorporation, liming can be done on the soil surface, without the need to repeat the operation of lime incorporation, ensuring high efficiency of P use even after more than four decades.

Lime incorporation up to 40 cm deep increases root growth and crop yield in highly weathered tropical soils

Soil acidity is still a factor limiting crop yield in tropical soils. Our objective was to evaluate lime incorporation into the 0–40 cm depth as a strategy to improve soil chemical conditions and root growth within the soil profile and crop yield in highly weathered tropical soils. Lime rates ranging from 0 to 15 Mg ha−1 were incorporated into the 0–40 cm depth in three Brazilian oxisols. Soil response to lime rates was evaluated in both 0–20 and 20–40 cm depths at the end of each spring/summer cropping season as were crop yields over three consecutive years after lime incorporation. Maize + Brachiaria ruziziensis roots were evaluated within the 0–60 cm depth three years after liming. Overall, incorporating lime significantly increased Ca2+ and Mg2+ contents, pH, and base saturation (BS) in the 0–40 cm depth, with lime rates ≥ 9 Mg ha−1 having the greatest positive impact. By improving soil chemical conditions, the incorporation of high lime doses (≥9 Mg ha−1) increased crop root growth in the soil profile (up to 60 cm deep) and led to higher rainfed crop yields. The highest annual crop yields were observed under lime rates between 9 and 15 Mg ha−1. Finally, incorporating high doses of lime into the soil profile decreased crop yield losses due to droughts. Combined, these results indicate that deep liming (40 cm) at the correct dose can increase the resilience of agricultural systems to water deficit and the yield potential of annual crops in highly weathered tropical soils.

Effects of form, fineness and placement of lime with and without soil tillage on barley and canola growth and development

No-tillage systems and slow movement of surface-applied limestone can lead to stratification of soil acidity. Incorporation of lime by tilling soil is not preferred by producers following conservation agriculture practices. There is limited research on ways to facilitate lime movement without soil disturbance. This study aimed to determine the effects of form, fineness and calcium carbonate equivalent (CCE) of calcitic lime on its movement in soil with or without different soil disturbance actions and consequent effects on productivity of barley (Hordeum vulgare L.) and canola (Brassica napus L.). A field trial was established in the Western Cape province, South Africa. Ten treatments included a control, lime with different forms and fineness, and tillage practices. Due to the slow movement and reactivity of lime in soil, it was unlikely that growth responses from barley or canola would be detected within the first two years following liming. A once-off strategic tillage action promoted crop growth. This was attributed to deeper redistribution of lime in the soil (15–30 cm depth), among secondary agronomic responses to tillage. Strategic once-off tillage may address the stratification of both soil acidity and nutrients, such as calcium (Ca) and magnesium (Mg), and could be considered as an option to incorporate into management of no-tillage production systems.

Improving Carbonate Saline Soil in a Seasonally Frozen Region Using Lime and Fly Ash

In this study, carbonate saline soil in the Duerbote of Songnen Plain was improved by adding lime and fly ash. The improved soil was exposed to 0, 30, and 60 freeze-thaw cycles, and ordinary triaxial compression tests (UU) were conducted under confining pressures of 100, 200, and 300 kPa. The effects of freeze-thaw cycles, lime content, fly ash content, and confining pressure on the peak deviatoric stress, cohesion, and internal friction angle on the lime-ash improved carbonate saline soil were analysed. The incorporation of lime and fly ash in carbonate saline soil transformed the stress-strain curves from the strain hardening type to strain softening type and also changed the strain corresponding to the peak deviatoric stress of the soil. The effect of lime on the shear strength of the soil was the most significant, and it significantly increased the peak deviatoric stress, cohesion, and internal friction angle of the soil. Similarly, the effect of fly ash on the peak deviatoric stress and internal friction angle of the soil was significant, but the effect on cohesion was very limited. A small amount of fly ash increased the peak deviatoric stress and internal friction angle of carbonate saline soil, but an excessive amount had the opposite effects. The freeze-thaw cycles cause the shear strength of the carbonate saline soil to decrease, but the incorporation of lime and fly ash alleviated this decrease.