Application Of Steel Slag Research Articles

Application of Steel Slag in Road Semi-Rigid Subgrade and its Volume Stability Modification Progress Study

Application of Steel Slag in Road Semi-Rigid Subgrade and its Volume Stability Modification Progress Study

Study on the Characteristics of Steel Slag and its Road Performance in Asphalt Mixture

Based on the characteristics of steel slag, the application progress of steel slag as aggregate in asphalt mixture is summarized. Firstly, the differences in mechanical properties, chemical composition and physical structure of steel slag aggregates treated by different methods are summarized. The surface structure of steel slag is rough and rich in edges and corners, showing good wear resistance and crushing resistance, but there are also problems such as high density, high water absorption and volume instability. Among them, volume instability is the key factor affecting the application of steel slag in asphalt mixture. Then, the effects of steel slag aggregate on the road performance of asphalt mixture, such as water stability, rutting resistance, high temperature stability and low temperature cracking resistance, are summarized in detail. It is found that steel slag instead of coarse aggregate in asphalt mixture can improve the performance of skid resistance, rutting resistance and fatigue resistance. The water damage performance is due to the different sources of steel slag, and the uncertainty of the change results is large. On the whole, steel slag instead of aggregate can improve the road performance to a certain extent, but the volume of steel slag aggregate is unstable, which may bring some variability. In the process of road application, targeted regulation should be carried out to ensure the stability of asphalt mixture performance.

Experimental and numerical evaluation of sustainable application of steel slag as an alternative to gravel in compaction piles

The study investigates the application of steel slag as an innovative material for compaction piles in the stabilization of soft soils, offering an eco-friendly alternative to conventional gravel compaction piles (GCPs). Through a comprehensive series of laboratory tests, field experiments, and numerical simulations, this study evaluated the performance, environmental impact, and long-term behavior of steel slag compaction piles (SSCPs). The key findings revealed that steel slag not only provides immediate soil improvement comparable to gravel but also exhibits significant time-dependent increases in strength and stiffness. Standard Penetration Test (SPT) N-ratios (N1/N0, where N1 = N value after improvement and N0 = N value before improvement) were similar for soils reinforced with SSCPs and GCPs after 0 months, but were about 30 % higher in SSCP-reinforced soils after 3 months. This increase was attributed to the cementation of steel slags, suggesting that the compaction pile with increased stiffness due to cementation acts as a compaction pile with an increased area replacement ratio (α). Environmental assessments confirmed that steel slag meets regulatory standards for soil contamination, positioning it as a sustainable option. Settlement analysis after embankment construction showed reduced and more uniform settlements with SSCPs, suggesting superior load distribution capabilities. Finite element analysis compared the behavior of SSCP-reinforced soils at varying α and stiffness of compaction piles, confirming that the cementation of steel slag produces an effect equivalent to increasing α in uncemented piles, thus enhancing the reinforcement effect.

Exploration of steel slag by lignin and sodium citrate modification for mechanical properties and stability of steel slag-cement cementitious materials

Steel slag is produced globally in huge annual quantities. How to achieve its large-scale utilization is a question that researchers have been exploring. In this work, sodium citrate (SC) was used as a linker to modify Steel slag (SS) with alkali lignin (AL). And steel slag cement cementitious materials (CSS) were prepared with 10% replacement ratio. The effects of AL and SC on CSS were investigated by X-ray diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Thermo-gravimetric analysis (TG/DTA) etc. The results indicated that AL successfully loaded on the surface of SS. For CSS, as the degree of modification increased, the standard consistency water consumption of CSS decreased from 27% to 23.5%. During the hydration of CSS, its main hydration product was Ca(OH)2, the suitable amounts of AL and SC can stimulate the activity of SS. In addition, SS modification could improve the stability of CSS. The results of Ray's clamp method showed that the addition of AL and SC made the expansion of CSS reduced from 1.5 to 0. The 3 d and 28 d of CSS maximum flexural strengths were 5.42 MPa and 8.61 MPa and the maximum compressive strengths were 22.96 MPa and 49.15 MPa, respectively. This was an increase of 36.67% and 48.27% respectively. Therefore, the combination of AL and SS can not only effectively solve the problem of AL resource utilization, but also is expected to realize the practical application of SS in cement cementitious materials. It has good social and environmental benefits.

Soil correction, growth, and nutrition of Panicum maximum in response to rates and methods of application of steel slag and limestone

The main objective of this study was to evaluate the effectiveness of a soil conditioner derived from steel slag (Agrosilicio Plus – ASP) compared to dolomitic limestone (DLS) in agriculture. The research questions were about how ASP compares to DLS in terms of soil acidity correction, productivity, and the nutritional status of the forage grass Panicum maximum cv. BRS Zuri. Two experiments were conducted in a greenhouse using plastic pots filled with a 0-20 cm layer of Ferrasol. In the first experiment, soil conditioners were applied on the surface, while in the second, they were incorporated into the soil. A complete block design with a 2 × 4 + 1 factorial arrangement was employed. The factors included two soil conditioners (ASP and DLS) at four application rates (25%, 50%, 100%, and 150% of the liming requirement). A control treatment without any conditioner application was also included. P. maximum was grown in three successive 45-day cropping cycles. The shoot dry mass and nutrient content in plants’ tissues were measured. Both ASP and DLS were effective in correcting soil acidity. The ASP led to a higher silicon accumulation in the plants, whereas DLS resulted in higher calcium accumulation. Increasing rates of both conditioners generally had positive effects on most variables measured. When applied on the surface, ASP led to higher dry mass production accumulated in three crops. ASP is a viable alternative to limestone for correcting soil acidity and supplying essential nutrients and silicon to BRS Zuri grass. Additionally, ASP can effectively be applied on the soil surface.

Effects of Steel Slag Used as Substrate on the Growth of Hydrangea macrophylla Cuttings

Steel slag is an industrial solid waste produced during the steelmaking process. To explore the application of steel slag in the agricultural field, the present experiment was carried out to study the effect of substrates with different contents of steel slag on the growth of Hydrangea macrophylla cuttings. The conventional substrate (perlite: vermiculite: peat = 1:1:1) was used as the control (CK), and the treatments were designed as T1 (steel slag: perlite: vermiculite: peat = 1:3:3:3, v/v/v/v), T2 (steel slag: perlite: vermiculite: peat = 1:2:2:2, v/v/v/v), T3 (steel slag: perlite: vermiculite: peat = 1:1:1:1, v/v/v/v), and T4 (steel slag: perlite: vermiculite: peat = 1:0:0:0, v/v/v/v). The results showed that the addition of steel slag significantly increased the substrate’s bulk density, EC, and pH and improved its water retention capacity to a certain extent. There were significant differences among different treatments in morphological indicators, root growth and development, and physiological and biochemical characteristics of cutting seedlings. All traits, including plant height, fresh weight, dry weight, root length, root surface area, root volume, the number of root tips, root activity, and soluble protein content of seedlings grown in T3 were significantly higher than those in other substrates. The results indicated that the appropriate addition of steel slag is helpful to hydrangea cuttings’ growth, and the optimal mixing ratio is steel slag: perlite: vermiculite: peat = 1:1:1:1 (v/v/v/v). This is a significant innovation in applying steel slag in agricultural production.

Bond between alkali-activated steel slag/fly ash lightweight mortar and concrete substrates: Strength and microscopic interactions

The fire-retardant lightweight mortar spalling from the tunnel lining substrates can threaten the safety of vehicles. The use of steel slag (SS) in alkali-activated cement can reduce the carbon emission and cost of lightweight mortar. The effects of SS on the bond strength and the microstructure of the interface between alkali-activated SS/fly ash (FA) lightweight mortar (ASFm) and concrete substrates was studied. The SS contents, namely, the mass ratio of SS to the summation of FA and SS, were 0 %, 20 %, 40 %, 60 %, and 80 %. The properties of ASFm, including compressive strength, fire resistance and bond strength, were studied. Results demonstrated that the bond strength of ASFm increases and then decreases with the increase in SS content. The highest bond strength of 0.65 MPa was obtained at 40 % SS content. Bond strength was determined by the pore structure and micromechanical properties of the matrix. When the SS content was increased from 0 % to 40 %, the content of C-A-S-H gel and C-N-A-S-H gel contents increased, and the porosity was reduced; hence, the bond strength of ASFm became larger. When the SS content increased from 40 % to 80 %, SS acted as an inhibitor, which reduced the micromechanical properties and increased the porosity of ASFm; therefore, the bond strength of ASFm decreased. This achievement provides an alternative way for the application of SS in tunnels.

Synergistic hydration mechanism of steel slag-metakaolin based on ionic dissolution properties combined with industrial CT analysis

Replacing cement with solid waste materials is a key approach to preserving natural resources and mitigating carbon dioxide emissions. In this research, we explored elemental complementation as an eco-friendly and low-carbon approach to develop composite cementitious materials (CCMs) by partially substituting cement with steel slag (SS) and metakaolin (MK), thereby overcoming the low reactivity of SS and facilitating its broader application. We scrutinized the synergistic effects of SS-MK CCMs on parameters such as solubility, water demand, setting time, compressive strength, the formation of hydration products, and microstructure. Employing a suite of analytical techniques, including Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), measurement of hydration heat, and X-ray computed tomography. The findings revealed that the alkaline environment produced by SS-cement powder promoted the breakdown of Si-O and Al-O bonds within MK, facilitating both the early hydration process and the development of strength.MK compensates for the lack of strength caused by the slow hydration of SS in the early stage, while the SS accelerated a pozzolanic reaction of MK, leading to a 28d compressive strength of 54.77 MPa for the composite, while the 28d strength of SS20 was 39.74 MPa; MK effectively utilized portlandite, enhancing the hydration of SS and increasing the production of calcium silicate hydrate, which optimized the pore structure and improved sphericity. Furthermore, the SS-MK CCMs addressed the issues of f-CaO excess and prolonged setting times in the SS-cement system, while also ameliorating the high calcium demand and reduced fluidity in the MK-cement system. Additionally, its lower cumulative heat release from hydration enhances the material’s volumetric stability. This study presents a strategy for the large-scale application of SS and contributes to the value-added, eco-friendly use of industrial solid wastes.

Unraveling the mechanisms of biochar and steel slag in alleviating lithium stress in tomato (Solanum lycopersicum L.) plants via modulation of antioxidant defense and methylglyoxal detoxification pathways

With progress in technology, soaring demand for lithium (Li) has led to its release into the environment. This study demonstrated the mitigation of the adverse effects of Li stress on tomato (Solanum lycopersicum L.) by the application of waste materials, namely coconut shell biochar (CBC) and steel slag (SS). To explore the impact of Li treatment on tomato plants different morphological, biochemical parameters and plant defense system were analyzed. Tomato plants exposed to Li had shorter roots and shoots, lower biomass and relative water contents, and showed decreases in physiological variables, as well as increases in electrolyte leakage and lipid peroxidation. However, the application of CBC and SS as passivators, either singly or in combination, increased growth variables of tomato and relieved Li-induced oxidative stress responses. The combined CBC and SS amendments reduced Li accumulation 82 and 90% in tomato roots and shoots, respectively, thereby minimizing the negative impacts of Li. Antioxidant enzymes SOD, CAT, APX and GR reflected 4, 5, 30, and 52% and glyoxalase enzymes I and II 7 and 250% enhancement in presence of both CBC and SS in Li treated soil, with a concurrent decrease in methylglyoxal content. Lithium treatment triggered oxidative stress, increased enzymatic and non-enzymatic antioxidant levels, and induced the synthesis of thiols and phytochelatins in roots and shoots. Hence, co-amendment with CBC and SS protected tomato plants from Li-induced oxidative damage by increasing antioxidant defenses and glyoxalase system activity. Both CBC, generated from agricultural waste, and SS, an industrial waste, are environmentally benign, safe, economical, and non-hazardous materials that can be easily applied on a large scale for crop production in Li-polluted soils. The present findings highlight the novel reutilization of waste materials as renewable assets to overcome soil Li problems and emphasize the conversion of waste into wealth and its potential for practical applications.

Effect of particle size and application rate of steel (Linz-Donawitz, LD) slag on heavy metal built-up in soil and their transfer dynamics in spinach (Spinacia oleracea L.)

Linz-Donawitz (LD) slag is a solid industrial waste generated during the production of steel. In general, the amount of LD slag produced varies from 300 to 400 kg ton-1 of steel. Presently only 25 % of the steel slag, which is also rich in various macro and micro-nutrients, is being reused in India compared to 70–100 % in other countries. The present study deals with the possibility of utilizing LD slagas a nutrient rich low-cost soil conditioner in agriculture. An experiment was thus conducted to determine the effect of LD slag application at rates 0.25, 0.50 and 1 t ha-1 in two particle sizes i.e., <50 and <100 microns (µ) on spinach (Spinacia oleracea L.). Physico-chemical, biological characteristics and heavy metals in soil and latter’s transfer from soil to the foliage was also determined. The results showed that an application of LD slag @1 tha-1 and 100 µ particle size significantly improved the soil microbial count and activity of enzymes such as dehydrogenase and phosphatase while at a smaller particle size of LD slag (50 µ) @ 1 tha-1, a significant increase in the foliage yield of spinach was observed. The risk due to heavy metals present in the steel slag as evidence by indicator of heavy metal content in plants i.e. transfer factor (TF), hazard quotient (HQ) and hazard index (HI) was within the permissible range. However long-term effect of steel slag application on ecotoxicity and phytotoxicity levels must be deciphered. In conclusion the application of LD slag in spinach does not negatively impact the soil health and in fact causes an increase in the economic yield of spinach.

Effect of Steel Slag on the Properties of Alkali-Activated Slag Material: A Comparative Study with Fly Ash.

Slag and fly ash (FA) are mostly used as precursors for the production of alkali-activated materials (AAMs). FA is the waste discharged by power plants, while slag and steel slag (SS) both belong to the iron and steel industry. The effects of SS and FA on the strength, microstructure, and volume stability of alkali-activated slag (AAS) materials with different water glass modulus (Ms) values were comparatively investigated. The results show that adding SS or FA decreases the compressive strength of AAS mortar, and the reduction effect of SS is more obvious at high Ms. SS or FA reduce the non-evaporable water content (Wn) of AAS paste. However, SS increases the long-term Wn of AAS paste at low Ms. The cumulative pore volume and porosity increase after adding SS or FA, especially after adding FA. The hydration products are mainly reticular C-(A)-S-H gels. Adding SS increases the Ca/Si ratio of C-(A)-S-H gel but decreases the Al/Si ratio. However, by mixing FA, the Ca/Si ratio is reduced and the Al/Si ratio is almost unchanged. The incorporation of SS or FA reduces the drying shrinkage of AAS mortar, especially when SS is added. Increasing Ms increases the compressive strength and improves the pore structure, and it significantly increases the drying shrinkage of all samples. This study provides theoretical guidance for the application of steel slag in the alkali-activated slag material.

Modification of steel slag to prepare chlorides based composite phase change materials with shape stability for high-temperature thermal energy storage

Using steel slag to prepare high-temperature (>500 °C) PCMs was an effective way to achieve its high value-added utilization as a potential heat storage medium in a variety of applications, such as solar energy storage, power peak shaving, and industrial waste heat recovery. However, the complex solid waste of steel slag might be corrosive to salt-based PCMs at high temperature. To address this issue, steel slag was firstly modified with another solid waste (i.e., CFA), which was then used to microencapsulate NaCl-KCl to prepare shape-stabilized C-PCMs in this work. Thermophysical and mechanical properties of C-PCMs were analyzed. Results showed that CFA modification greatly improved chemical compatibility between steel slag and eutectic salt through phase reconstruction. Steel slag modified with 30 wt% CFA at 1100 °C was identified as the optimum skeleton. The prepared C-PCMs containing 50 wt% salt showed a phase transition temperature of 653 °C with a high latent heat of 139 J/g and an excellent cycling stability. Additionally, its thermal conductivity reached 1.46 W/(m·K), 180 % higher than of pure salt. Compressive strength of the composite could be as high as 119 MPa, superior to other salt-based C-PCMs. A heat storage device was further designed to allow the numerical investigation of thermal performance of the prepared C-PCMs in practical conditions. Attributed by reasonable arrangement of bricks, the heat storage device possessed a uniform temperature distribution over the vertical cross-section of HTF, which contributed to a quick completion of charging and discharging process. This work could potentially lay a foundation for application of steel slag in the field of high-temperature thermal energy storage.

Research progress of hydrogen production and CO2 fixation in molten slag cooling process

AbstractSteel slag is a waste discharged from the iron and steel smelting process, which has the characteristics of large output, high temperature, complex chemical composition and poor stability. The application of steel slag in hydrogen production and CO2 fixation is of great significance for reducing energy consumption, obtaining renewable energy and fixing CO2 in the air. In this paper, the research progress of high‐temperature sensible heat of steel slag used for hydrogen production and CO2 fixation at medium and low temperature is introduced, the reaction mechanism of different hydrogen production methods and the treatment path and direction of high‐efficiency hydrogen production in the future are deeply analyzed, and the steel slag used for CO2 fixation is discussed and summarized from the theory, effect and treatment mode of CO2 fixation. In the future, the research on the economic benefits of hydrogen production and CO2 fixation from steel slag is a major focus, which can achieve economic benefits while utilizing steel slag resources.

In-situ investigation on the carbonation behaviors of various mineral phases in steel slag: The role of RO phase

Exploring the mineral compositions of steel slag and the microstructure evolutions of its carbonation products is very important for deeply understanding the carbonation mechanism of steel slag, which can promote the application of steel slag in carbon capture and storage. In this paper, the carbonation behaviors of various mineral phases in steel slag were investigated by using an ingenious in-situ observation method through combing laser scanning confocal microscopy (LSCM), backscattered scanning electron microscopy (BSEM) and focused ion beam-transmission electron microscope (FIB-TEM). It is shown that dicalcium silicate (C2S) and free lime (f-CaO) had high carbonation reactivity, while the calcium aluminoferrite with different Al/Fe ratios and mayenite (C12A7) exhibited extremely poor carbonation reactivity. The carbonation reactivity of RO phase was positively correlated with its Mg/(Fe + Mn) ratio. RO phase with a Mg/(Fe + Mn) ratio below 0.5 owned almost no carbonation reactivity, while the Mg2+ would leach from RO phase with a Mg/(Fe + Mn) ratio higher than 2.0 during the carbonation process, inhibiting the precipitation of CaCO3, changing the micro morphology of CaCO3, and generating spheroidal aragonite. The ingenious in-situ observation method developed in this study provides a very visual information, which can be further extended to more fundamental research.

Analyzing the Mechanical and Durability Characteristics of Steel Slag-Infused Asphalt Concrete in Roadway Construction

Steel slag is a solid byproduct of the steelmaking process, widely generated in the metallurgical industry. Due to its alkaline nature and excellent adhesive properties with asphalt, it represents a potential road construction material with outstanding road performance, making it well-suited for utilization in highway construction. This paper conducts a systematic analysis of the physical and chemical properties of steel slag, specifically South Steel Electric Furnace slag, and compares it with natural basalt and limestone aggregates. The aim is to establish a foundation for the application of steel slag in asphalt mixtures. Building upon this foundation, we carry out proportioning design for AC-13C and SMA-13 steel slag asphalt mixtures, followed by a comprehensive study of their high-temperature stability, low-temperature stability, water stability, and fatigue performance. Our research reveals variations in the chemical composition of different steel slags, with CaO, SiO2, and Fe2O3 being the primary components. The content of harmful elements varies depending on the steelmaking raw materials and additives used. Notably, the optimum asphalt-to-aggregate ratios for AC-13C and SMA-13 significantly surpass the specified requirements. The freeze–thaw splitting strength ratio and residual stability of steel slag AC-13C and SMA-13 asphalt mixtures exceed the specified requirements, with AC-13C demonstrating the highest water stability, boasting a freeze–thaw splitting strength ratio of 94.07%, and a residual stability of 93.8%. In terms of fatigue characteristics, SMA-13 exhibits a longer fatigue life than AC-13C, indicating superior fatigue performance for steel slag SMA-13. Steel slag enhances the abrasion resistance and rutting resistance of asphalt pavement surface layers, fully meeting the performance requirements for high-grade road surface layers.

Influence of the Steel Slag Particle Size on the Mechanical Properties and Microstructure of Concrete

The present paper probes into the influence of the steel slag particle size on the mechanical properties and microstructure of concrete, with steel slag serving as the primary raw material. Steel slag with different particle sizes was selected as the partial substitute material for concrete by mechanical grinding. The influence of steel slag on the compressive strength, bending strength, and microstructure of concrete was determined by laser particle size analyzer, specific surface area analyzer, strength experiment, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that mechanical grinding has significant effects on the particle size distribution and specific surface area of the steel slag. The optimal grinding time is 20 min and the specific surface area is 0.65 m2/g. D10, D50 and D90 are 0.91 μm, 16.57 μm and 46.40 μm, respectively. The steel slag with a fine particle size can better fill the pores in concrete and improve the compactness, thus enhancing the mechanical properties of concrete. The change in the steel slag particle size does not change the type of hydration products, but the smaller the particle size of steel slag, the better the gelling activity, the larger the hydration products, the denser the structure, and the better the mechanical properties. Therefore, the present study provides an important theoretical basis and practical guidance for the application of steel slag as an additive in the concrete industry.

Effect of Fe and Mn on the hydration activity of f-CaO in steel slag

Poor stability problems, mainly caused by f-CaO, limit the application of steel slag as a supplementary cementitious material. In order to investigate the effect of elemental composition on the hydration activity of f-CaO, synthetic f-CaO was prepared based on the elemental composition of f-CaO in steel slag, hydration experiments were carried out under ambient and boiling conditions, and the effect of the Fe and Mn on the hydration activity of f-CaO was interpreted from the point of view of the electronic structure based on Density functional theory. The results show that the synthetic f-CaO has a low hydration activity, while the changes of Fe and Mn elements affect the hydration activity of the synthetic f-CaO.The analysis of PDOS shows that the doping of both Fe and Mn inhibits the hydration activity of CaO and the inhibition effect of Mn is stronger.

Quantitative characterization and evaluation of key physicochemical characteristics of steel slag

Steel slag is considered to improve the road performance of cold mixed asphalt (CMA) due to its superior physicochemical characteristics. To realize the potential application of steel slag in CMA pavement, the alkalinity, hydration activity, pore characteristics, and three-dimensional (3D) morphology were quantitatively characterized and evaluated based on the X-ray fluorescence (XRF), mercury intrusion porosimetry (MIP), 3D laser scanning, and 3D structured light measurement, respectively. The results show that the alkalinity of steel slag can not fully reflect its hydration activity. Most steel slag has high alkalinity with an alkalinity value greater than 2.5, while the activity index (AI) is generally less than 1.0. The pores of steel slag are mostly "ink-bottle" shaped, in which macropores are the most developed, and small pores and micropores are the least developed. The total pore volume of macropores is the largest, while the total pore area of small pores is the largest. The porosity of porous, less porous, and dense steel slag is 12.05%, 6.88%, and 1.28%, respectively. The adsorption and accommodation capacity of porous steel slag for fluids is the largest, followed by less porous and dense steel slag. All three steel slags have good 3D shapes, and their shape factor (SF), sphericity (S), needle degree (ND), and flake degree (FD) have distribution intervals of 0.81–1.19, 0.70–0.99, 1.01–1.90, and 1.01–1.51, respectively. Porous steel slag shows richer apparent morphology than less porous and dense steel slag. Their apparent morphology characterization indicators Ra, Rq, Rp, Rv, and Rt show a good linear positive correlation with porosity, which can be regarded as the classification criterion for apparent morphology. This study will help enrich the theoretical basis and control indicator system for applying steel slag in CMA pavement.

Research Progress on the Application of Steel Slag in Water Treatment

As the economy evolves swiftly, the significance of the iron and steel sector in the national economy has grown, yet concurrently, it generates a substantial quantity of steel slag. Steel slag, a form of industrial refuse posing possible environmental risks, presents an immediate challenge in its logical usage and treatment. Lately, there has been significant focus on studying how steel slag is applied in environmental treatment. The article presents an overview of the material makeup, physical, and chemical characteristics of steel slag, and encapsulates the advancements in its application research for water treatment in recent times. Concurrently, this document highlights the difficulties and hurdles associated with steel slag, along with an exploration of its potential applications and future development paths.

The mechanical strength, microstructure, and transport properties of steel slag reinforced loess soil system

Steel slag, as an industrial byproduct obtained from the steel manufacturing industry, may cause land occupation, resource waste, and environmental pollution. The application of steel slag as a material for soil reinforcement in road engineering is very popular due to its potential hydration activity. The unconfined compression strength, microstructure, and transport properties of loess soil with cement, lime and steel slag were investigated. The results show that the loess soil can be reinforced by cement, lime, and steel slag to varying degrees. The reinforcement mechanism of cement for loess soil is realized by pore filling by cement hydration products such as CH, C-S-H and AFt, and their unconfined compression strength is improved by reducing the porosity. The reinforcement mechanism of lime for loess soil is achieved by pore filling by hydration products such as CH and CaCO3, and their strength is improved by a refined pore structure where the porosity has not been significantly reduced. The reinforcement mechanism of steel slag for loess soil is a combined mechanism of cement and lime, including pore filling and refined pores. The pore structure of reinforced soil can be studied at different scales by the MIP, LF NMR, and X-CT test methods. The transport properties including diffusivity and permeability of reinforcing soil can be well explored by Avizo software based on the microstructure obtained from X-CT.