Lime-activated ground granulated blast furnace slag (GGBS) is usually used to treat gypseous soils. However, sulphate-bearing soils often contain other sulphates, e.g., sodium sulphate (Na2SO4), potassium sulphate (K2SO4) and magnesium sulphate (MgSO4). Therefore, in this study, lime-GGBS was used as a curing agent for stabilising four sulphate-bearing soils, which were named as Na-soil, K-soil, Mg-soil, and Ca-soil. Unconfined compressive strength (UCS), swelling, X-ray diffraction, scanning electron microscopy and inductively coupled plasma spectroscopy tests, were conducted to explore the macro- and micro-properties of the lime-GGBS-stabilised soils. The results showed that at 5000 ppm sulphate, stabilised Mg-soil had the lowest swelling and highest UCS. At 20,000 ppm sulphate, stabilised Ca-soil had the lowest swelling, while stabilised Na-soil had the highest UCS. Generally, increasing sulphate concentration decreased swelling for Ca-soil but increased for other three soils, and decreased UCS for Mg-soil but increased for other three soils. This was because less ettringite was generated in the stabilised Ca-soil and the formation of magnesium silicate hydrate (MSH) in the stabilised Mg-soil. Therefore, the sulphate type had a significant impact on the swelling and strength properties of lime-GGBS-stabilised sulphate-bearing soil. It is essential to identify the sulphate type before stabilising the soil on-site.

Thallium sulphate (TLM) is a highly hazardous metal known to induce severe renal damage. Syringetin (SGN) is a naturally derived polyphenolic compound that demonstrates excellent medicinal properties. This research trial was conducted to determine the nephroprotective ability of SGN to inhibit TLM induced renal toxicity in rats by assessing different parameters including oxidative stress, apoptotic and inflammatory markers as well as histomorphological parameters. Thirty-two Sprague Dawley rats were apportioned into the control, TLM (6.4 mgkg- 1), TLM (6.4 mgkg- 1) + SGN (10 mgkg- 1) and SGN (10 mgkg- 1) alone administered group. Our findings revealed that TLM exposure promoted renal inflammation which was evident by increased mRNA expression of myeloid differentiation primary response 88 (MYD88), toll-like receptor 4 (TLR4), interleukin-1 beta (IL-1 beta), high mobility group box1 (HMGB1), tumor necrosis factor- alpha (TNF-alpha), receptor for advanced glycation end products (RAGE), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and nuclear factor- kappa B (NF-kappa B). The concentrations of reactive oxygen species (ROS) and malondialdehyde (MDA) were exacerbated while the enzymatic action of heme oxygenase-1 (HO-1), superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT), & tissue contents of glutathione (GSH) were reduced after TLM intoxication. Serum concentrations of N-Acetylglucosamine (NAG), blood urea nitrogen (BUN), Kidney Injury Molecule-1 (KIM-1), Neutrophil Gelatinase-Associated Lipocalin (NGAL), creatinine, uric acid were observed elevated while a notable reduction was noted in the concentration of creatinine clearance following the dose administration of TLM. The levels of Bcl-2-associated X protein (Bax), cysteine-aspartic acid protease-3 (Caspase-3) & cysteine-aspartic acid protease-9 (Caspase-9) were exacerbated while the concentration of B-cell lymphoma-2 (Bcl-2) was notably suppressed following regimen of TLM. Renal tissues were distorted after TLM administration. In contrast, SGN supplementation notably restored oxidative profile, reduced pro-inflammatory and apoptotic markers as well as improved renal histology.

The sulphated gravel embankment in seasonal frozen soil regions may experience deformation problems such as salt expansion, frost heave, and settlement under rainfall percolation conditions and changes in environmental temperature, affecting considerably its normal use. In response to these issues, relying on the renovation and expansion project of an international airport in northwest China, this paper used a self-designed temperature control testing device and conducted indoor constant temperature tests and freeze-thaw cycle tests using on-site natural embankment filling, and conducted numerical simulation tests using the COMSOL Multiphysics software programme. This paper investigated the characteristics of temperature variation, moisture, salt migration, and deformation of sulphated gravel in seasonal frozen soil regions under rainfall percolation conditions. The results indicated that under environmental temperature changes in the range of- 10-25 degrees C, the temperature at which sulphated gravel salt expansion and frost heave occur was approximately-8 degrees C, and the deformation sensitive depth range from 0 to 200 mm. The moisture and salt contents of soil samples would experience a sudden increase due to rainfall percolation, with the sudden increase in moisture in the soil sample with a salt content of 0.9 % lagging that of the soil sample with a salt content of 0.5 % by one freeze-thaw cycle. Rainfall percolation significantly enhanced the settlement deformation of sulphated gravel during freeze-thaw cycles. The primary causes of soil deformation include the upward migration of water vapour, the downward percolation of moisture, and rainfall. These factors contribute to the destruction of the soil structure and alter the contact modes between soil particles, resulting in soil loosening and settlement deformation.

Concrete structures located in environments such as oceans, salt soils, and salt lakes are not only subjected to the sustained action of loads, but also to the erosive attack of sulphate ions at the same time, leading to changes in their mechanical properties. This paper focuses on the development of the mechanical properties of fly ash concrete over time, targeting axially compressed fly ash concrete components in a sulfate erosion environment. Under a stress level of 20 %, the paper takes into account factors such as fly ash contents of 25 %, 50 % and 75 %, loading ages of 28d, 90d and 120d, and sulphate solution concentrations of 2 %, 6 % and 10 %, respectively, conducting experimental research on the evolution of mechanical properties after the coupling effects of sustained load and sulfate erosion. Subsequently, the mechanism and law of evolution of axial compressive strength and modulus of elasticity of fly ash concrete after sustained loading coupled with sulphate erosion are analyzed. By using the concrete Compressible Packing Model (CPM) and the Triple-Sphere Model (TSM), along with a durability analysis of fly ash concrete under sustained loading, the calculation models of axial compressive strength, as well as the elastic modulus of fly ash concrete after the coupled action of sustained loading and sulphate erosion are established respectively. Finally, the model established in this paper is evaluated through data analysis using deviation analysis, the Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) methods, comparing it with existing models and experimental results. The research results show that, in terms of deviation analysis, the model established in this paper has a deviation of less than 1.5 % compared to the test data for elasticity modulus, and a deviation of less than 2 % compared to the test data for compressive strength. In terms of Root Mean Square Error (RMSE) and Mean Absolute Error (MAE), the model's errors compared to the experimental results for elasticity modulus and compressive strength are within 0.5. The comparison shows that the calculation results of the mechanical properties model of fly ash concrete constructed in this paper are in good agreement with the test data. The significance of the research lies in its ability to provide a theoretical basis for understanding the long-term performance development law of fly ash concrete structures in sulphate erosion environment.

Based on the real exposure field environmental conditions in the field, this paper investigates the strength evolution of concrete in long-term service under the coupling of corrosion-freeze-thaw-large temperature difference in saline soil area, and reveals the intrinsic mechanism of the change of concrete mechanical properties through NMR, XRD, FTIR, SEM-EDS tests. The findings of this study demonstrated that adding fly ash (FA) and slag powder (SP) to concrete could effectively improve its physico-mechanical properties after six years of corrosion in saline soil. The concrete incorporated with 10% SP exhibited the lowest surface damage and the greatest compressive strength. The internal porosity of concrete with 30 % FA, 10 % SP and 20% SP is less than that of normal concrete. These changes optimised the pore structure and supported the idea of an intrinsic strength-evolving mechanism. The crystalline expansion of sodium sulphate is an important factor leading to the decline in concrete performance in saline soil areas. Mixing 30% FA, 10% SP, and 20% SP promoted the hydration of concrete to generate CSH and calcite generated by the carbonation of CH fills the pores in the concrete, increasing the concrete compactness and strength and further preventing the infiltration of SO42-and Cl-. This also reduced the generation of corrosion products such as ettringite, gypsum, thaumasite, and others. By analysing the macro-performance changes and micro-mechanisms, it was found that 10% SP internal mixing demonstrated the best effect on the performance enhancement of concrete piles in a real environment in saline soil areas for up to six years.

Presence of sulphates in lime-stabilised soils can lead to a reduction in long term strength, which can have adverse effects on construction and engineering projects. The present study focuses on addressing the challenges posed by sulphate content in lime-stabilised Kuttanad marine clays. By introducing 6% lime and 4% sulphates (sodium sulphate and lithium sulphate) to untreated clay, the research aims to investigate the effect of sulphates in these clays. To mitigate sulphate-related issue, barium hydroxide, in both its pure laboratory form and the commercial variant baryta, was employed to develop an effective mitigation strategy for strength reduction. Unconfined compression tests were conducted on lime-treated clay both with and without additives, immediately after preparation and over 1 week, 1 month, 3 months, 6 months, 1 year and 2 years of curing. Test results indicated that both sodium sulphate and lithium sulphate negatively impact the strength gain of lime-stabilised clay, with lithium sulphate having a more detrimental effect. There was a consistent improvement in shear strength with the addition of both barium hydroxide and baryta. The results of SEM and XRD analysis also align with the above findings. When twice the predetermined quantity of baryta was added, it outperformed pure barium hydroxide in terms of shear strength enhancement. The cost-effective nature of baryta, being a mere quarter of the price of pure barium hydroxide, makes it a viable alternative for addressing the strength loss in lime-stabilised sulphate bearing Kuttanad marine clays.

Sulfate saline soils are widely distributed in Xinjiang, where salt expansion often leads to road cracking and damage. This study investigated the effectiveness of a method that combines fly ash, slag, and polyacrylamide (PAM) in treating saline soils. Various tests, including salt expansion, boundary moisture content, pH, total dissolved solids (TDS), electrical conductivity (EC), sulfate ion concentration, unconfined compressive strength, and freeze-thaw cycle tests, were conducted to evaluate the mechanical and physicochemical properties of the solidified soil. Moreover, scanning electron microscopy (SEM) was utilized to explore the enhancement mechanism and microscopic features. The results indicate that the inorganic-organic combination of fly ash, slag, and polyacrylamide effectively suppresses salt expansion in sulfate saline soil, enhancing its mechanical properties, plasticity, and frost resistance. Considering economic feasibility and practicality, the optimal ratio was determined: a mixture of fly ash, slag, and PAM at 15%, with PAM at 2%. Under these conditions, the treatment exhibits the most efficient inhibition of salt expansion and improves structural integrity. The 7-day unconfined compressive strength of the treated soil reaches 993 kPa, three times higher than that of natural soil. Additionally, the soil demonstrates a significant enhancement in freeze-thaw resistance.

The rapid changes in the pattern of atmospheric warming as well as the degradation of glaciers in the Himalayas point to the inevitability of accurate source characterization and quantification of the impact of aerosols. In this regard, optical and chemical properties of aerosols, and their role in radiative effects are examined over a remote high-altitude site Lachung (27.4 degrees N, 88.4 degrees E, 2700 m a.s.l.) in the eastern Himalayas during August-2018 to February-2020. It is found that the sulphate (SO42- ) and carbonaceous aerosols (both organic carbon - OC and elemental carbon - EC) significantly contribute to the total aerosol mass loading in winter (DJF) and spring (MAM), resulting in high values of scattering and absorption coefficients. Aerosol single scattering albedo (SSA) is relatively higher in winter ( 0.85) due to a significantly higher amount of OC (OC/EC > 8). However, SSA 0.8 in spring despite of higher SO42- concentrations (SO42- /EC > 4.0 and SO42-/OC - 1.0) than winter. A reverse pattern is seen in summer-monsoon (JJAS) having lower SO42-/EC < 2 and SO42- /OC < 0.5, resulting in SSA as low as -0.64. The seasonal values of aerosol direct radiative forcing in the top of the atmosphere (DRFTOA) are as high as -2.9 +/- 1.2 Wm- 2 during the period of abundant OC in winter and -2.8 +/- 0.5 Wm- 2 during the period of abundant SO42- in spring. The combined effect of carbonaceous and SO42- aerosols on the surface cooling is highest in spring (-16.7 +/- 4.9 Wm- 2). DRF in the atmosphere is also - 34% higher in spring (13.8 +/- 4.5 Wm- 2, which translates to an atmospheric heating rate of - 0.39 K day-1), than in winter. The seasonal pattern of forcing influenced by the heterogeneous sources and chemical composition of aerosols over the eastern Himalayan site is significantly influenced by the transport of aerosols from the Indo-Gangetic Plains of India.

Three global chemistry-transport models (CTM) are used to quantify the radiative forcing (RF) from aviation NOx emissions, and the resultant reductions in RF from coupling NOx to aerosols via heterogeneous chemistry. One of the models calculates the changes due to aviation black carbon (BC) and sulphate aerosols and their direct RF, as well as the BC indirect effect on cirrus cloudiness. The surface area density of sulphate aerosols is then passed to the other models to compare the resulting photochemical perturbations on NOx through heterogeneous chemical reactions. The perturbation on O-3 and CH4 (via OH) is finally evaluated, considering both short- and long-term O-3 responses. Ozone RF is calculated using the monthly averaged output of the three CTMs in two independent radiative transfer codes. According to the models, column ozone and CH4 lifetime changes due to coupled NOx/aerosol emissions are, on average, +0.56 Dobson Units (DU) and -1.1 months, respectively, for atmospheric conditions and aviation emissions representative of the year 2006, with an RF of +16.4 and -10.2 mW/m(2) for O-3 and CH4, respectively. Sulphate aerosol induced changes on ozone column and CH4 lifetime account for -0.028 DU and +0.04 months, respectively, with corresponding RFs of -0.63 and +0.36 mW/m(2). Soot-cirrus forcing is calculated to be 4.9 mW/m(2).

A box model has been used to compare the burdens, optical depths and direct radiative forcing from anthropogenic PM2.5 aerosol constituents over the Indian subcontinent. A PM2.5 emission inventory from India for 1990, compiled for the first time, placed anthropogenic aerosol emissions at 12.6 Tg yr(-1). The contribution from various aerosol constituents was 28% sulphate, 25% mineral (clay), 23% fly-ash, 20% organic matter and 4% black carbon. Fossil fuel combustion and biomass burning accounted for 68% and 32%, respectively, of the combustion aerosol emissions. The monthly mean aerosol burdens ranged from 4.9 to 54.4 mg m(-2) with an annual average of 18.4 +/- 22.1 mg m(-2). The largest contribution was from fly-ash from burning of coal (40%), which has a high average ash content of 30%. This was followed by contributions of organic matter (23 %) and sulphate (22%). Alkaline constituents of fly-ash could neutralise rainfall acidity and contribute to the observed high rainfall alkalinity in this region. The estimated annual average optical depth was 0.08 +/- 0.06, with sulphate accounting For 36%, organic matter for 32% and black carbon for 13%, in general agreement with those of Satheesh et al. (1999). The mineral aerosol contribution (5%) was lower than that from the previous study because of wet deposition from high rainfall in the months of high emissions and the complete mixing assumption in the box model. The annual average radiative forcing was - 1.73 +/- 1.93 W m-2 with contributions of 49% from sulphate aerosols, followed by organic matter (26%), black carbon (11%) and fly-ash (11%). These results indicate the importance of organic matter and fly-ash to atmospheric optical and radiative effects. The uncertainties in estimated parameters range 80-120% and result largely from uncertainties in emission and wet deposition rates. Therefore, improvement is required in the emissions estimates and scavenging ratios, to increase confidence in these predictions. (C) 2000 Elsevier Science Ltd. All rights reserved.