Backfill Material Research Articles

Study on the fluidity and mechanical properties of multi-source coal-based solid waste (MCSW) filling material

The backfilling mining technology for multi-source coal-based solid waste (MCSW) aligns with the key challenges and emerging paradigms in the coal industry, aiming at intelligent and cleaner coal mining, high efficiency, and low carbon utilization. This research area has gained considerable attention and significance for promoting high-quality coal mining, low environmental impact, and sustainable development. In this study, a response surface experiment was designed with desulfurization gypsum (DG), gasification slag (GS), and furnace bottom slag (FBS) as factors to analyze the performance of backfill materials with varying compositions. Parameters such as bleeding rate, compactness, viscosity, setting time, and age strength were tested. An optimal composition of backfill materials was obtained, with a MCSW content exceeding 90 %, 28-day strength exceeding 2 MPa, initial setting time between 240 and 480 min, and final setting time ranging from 300 to 600 min. The investigation of the optimal materials involved characterizing the pore structure, microstructure, composition, and silica gel structure through techniques such as X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Additionally, the study explored micro-interface structures and enhancement mechanisms. After 28 days of curing, the backfill with a composition of DG 0.3, FBS 0.2, GS 0.1 exhibited a compressive strength of 5.18 MPa, with an initial setting time as short as 140 min. This can be attributed to the precipitation of silica gel on the grain surface, which mitigated the segregation effect. The silica gel promoted inter-particle bonding and rapid viscosity, preventing particle settling. This method not only ensures the safe disposal of coal-based solid waste but also contributes to the coordinated development of coal resource exploitation, environmental protection, and reduced carbon footprint.

Study on Controlled Low-Strength Materials Using Ultra-Rapid-Hardening Cement and Stone Sludge for Backfill and Subbase Application in Road Excavation and Restoration Work

A significant amount of stone sludge is generated as a by-product during the production of crushed stone aggregate, and most of it is disposed of in landfill as waste. In order to recycle this stone sludge, this study evaluated a controlled low-strength material (CLSM) using ultra-rapid-hardening cement and stone sludge for application as backfill and subbase material for road excavation and restoration work. In addition, considering the limited construction time of excavation and restoration work in urban areas, backfill and subbase materials must simultaneously satisfy conditions of fluidity, workability, quick curing time, and certain levels of strength. Therefore, in this study, CLSM was manufactured according to various mixing ratios and flow, slump, and compressive strength tests with age were evaluated. Additionally, the change trend in the microstructure of the CLSM with age was analyzed. Through indoor experiments, the optimal mixing ratios for backfill and subbase CLSM were determined, and field applicability and performance of field samples were evaluated through small-scale field construction. It was concluded that CLSM, which contains a large amount of stone sludge, can be sufficiently applied as a backfill and subbase material for excavation and restoration work if appropriate admixtures are adjusted according to the weather conditions at sites.

Analysis of the effects of using various backfill materials in the buried pipelines construction

Analysis of the effects of using various backfill materials in the buried pipelines construction

Study on Aeolian Sand-Box Backfill Geomechanical Characteristics and Overlying Strata Control Effects

The aeolian sand-box backfilling method proves effective for environmentally friendly coal extraction in northwestern regions, including Xinjiang. This study investigated the geomechanical characteristics of aeolian sand-box backfill material and its control effects on overlying strata through indoor experiments, mechanical analysis, and numerical simulations. Uniaxial compression tests on models with varying mesh sizes, wire diameters, and dimensions revealed that larger mesh sizes and wire diameters increased the bearing capacity of the aeolian sand-box backfill material, while increasing dimensions had the opposite effect. A mechanical analysis of the metal mesh box deformation produced equations describing its restraining force. Subsequent experiments and simulations on models of different dimensions consistently demonstrated the material’s mechanical properties, with stress-displacement curves closely aligned. 3DEC5.2 software simulations highlighted the effectiveness of aeolian sand-box backfill material in controlling displacement and stress variations in goaf areas. Notably, smaller-sized backfill material exhibited a more pronounced impact on controlling overlying strata displacement and stress development.

Energy evolution and mechanical properties of modified magnesium slag-based backfill materials at different curing temperatures

To study the mechanical properties and failure characteristics of all-solid waste cementitious materials prepared in the intense geothermal environment of deep mines. Uniaxial compression, acoustic emission (AE), SEM and other tests were adopted to characterize the energy and deformation failure of backfill materials from different temperatures (20 °C, 30 °C, 40 °C). The results show that the temperature has a promoting effect on the development of modified magnesium slag-fly ash cemented paste backfill (MFPB) strength. The elastic strain energy and the dissipated energy corresponding to the peak stress increase as the curing temperature increases. The high frequency phase of the energy scatter plot is accompanied by a rapid increase in the cumulative ringing count and cumulative energy. Tensile cracks increase with the increase of curing temperature. The temperature effectively promotes the hydration process of MFPB. The decrease of strength in the later stage of curing temperature 40 °C is due to the harmful thermal stress within the backfill. The results provide theoretical guidance for the practical application of MFPB.

The Influence of Backfill on the Driving Energy Intensity and Axial Load Resistance of Piles with Shaft Widenings: Modeling Research

This article is dedicated to addressing the current challenge of augmenting the load-bearingcapability of pile foundations. This predicament is most effectively addressed by employing piles with unconventional geometries along with atypical methodologies for installing these foundation piles. The primary objective of the research wasto examine the impact of various fill materials (including both soil and rigid substances) on the energy consumption during pile driving and the resistance to static loads by piles with multiple shaft expansions. The findings derived from model-based investigations demonstrate that the load-bearing capacity of piles with shaft expansions installed with bulk material filling surpassed that of conventional piles (prismatic and pyramidal) by a factor ranging from 1.5 to 4.6. Furthermore, the research outcomes also indicated greater energy consumption (1.14–1.66 times) and enhanced load-bearing capacity (1.15–1.68 times) for piles with shaft expansions driven with backfill in comparison to piles installed without backfill. It is noteworthy that the type of backfill material significantly influenced the energy consumption during pile driving and their stability under axial static loads. The correlation relationships can be applied to approximate projection of the energy-related and structural parameters of piles with shaft expansions embedded with the addition of bulk materials.

Mechanical properties evaluation of waste gangue-based cemented backfill materials based on an improved response surface model.

Traditional mining methods damage the cultivated land and produce gangue waste that often contaminates the environment. Yet, these problems can be mitigated by transforming the waste into gangue-based cemented backfill material (GCBM), whose mechanical properties are crucial for surface protection. Therefore, in this study, an intelligent model based on laboratory tests was developed to evaluate the GCBM's mechanical properties. The strength tests and polynomial response surface model (PRSM) were used to analyze the non-linear correlation between the influencing factors and the uniaxial compressive strength (UCS). Meanwhile, the importance of multidimensional factors was analyzed by the mean impact value, revealing that concentration and gangue proportion are the most sensitive factors. In addition, an intelligent response surface model (IRSM) based on support vector regression model was constructed by enhancing an optimization algorithm with chaotic mapping and adaptive methods. The performance of the traditional PRSM and the novel IRSM was compared, and the IRSM was validated. The IRSM can predict UCS more efficiently and effectively than the traditional PRSM under high-dimensional factors, with R2 of 0.96 and MBE of 0.05. This indicated that the IRSM has the potential to promote coal mine waste reduction and environmental protection.

Hydration mechanism of calcium chloride modified coal gasification slag-based backfill materials

To address the environmental pollution and resource wastage caused by the massive stockpiling of coal gasification slag (CGS), in this study, chlorine salt (CaCl2, CC) was adopted to stimulate the potential volcanic ash activity of CGS and to prepare a new modified CGS-based cementitious backfill material (MC-CPB). The optimum CC admixture was determined by comparing the compressive strength, and the effect of different admixtures on the strength of the MC-CPB was investigated. The effects of the CC content on the hydration properties and the composition and the micro-morphology of the hydration products of the MC-CPB were analyzed using hydration heat, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry (TG) analyses. It was found that the addition of CC promoted the early and mid-strength of the MC-CPB, but an excessive amount of CC (>1%) inhibited the development of the strength in the later stages. A concentration of 1% CC had the best effect on the strength of the MC-CPB in the entire age range, increasing the compressive strength from 3 to 90 days by 65.8%, 56.1%, 80.6%, 30.9%, and 31% compared to the control group. The CC accelerated the hydration reaction process of the MC-CPB by shortening the durations of the induction and acceleration periods, and it enhanced the hydration reaction intensity of the MC-CPB by increasing the second release heat peak and forming a third release heat peak. The MC-CPB sample containing CC generated a new hydration product, Friedel’s salt, which increased the compactness of the matrix and thus improved the compressive strength of the sample. However, excessive addition of CC reduced the amount of Ettringite (AFt) generated in the later stage, leading to a decrease in the strength of the high CC content samples in the later stage. The results of this study promote the large-scale and resourceful use of CGS in mine backfill and provide a theoretical basis for the field proportioning design and industrial application of MC-CPB for backfill.

DEFORMATION FEATURES OF EMBEDDED MATERIALS UNDER COMPRESSION CONDITIONS

Purpose. The purpose of the article is t o study the deformation characteristics of the backfill materials made of crushed rock of different granulometric composition under compression conditions to assess the stability of the side rocks in a coal massif with preparatory workings when selecting the parameters of protective structures. Methods. Compression tests were carried out in the laboratory to model the behaviour of crushed rock fill materials under load. Cylindrical specimens were subjected to axial static compression without the possibility of lateral expansion. The results. It has been experimentally established that the maximum value of the compaction coefficient of the crushed rock kс=1.57 is achieved under conditions of compression, when the relative change in the volume of the source material is 35-36% and the relative void is 5-6%. Under such conditions, the ultimate compressibility of the deformable body is achieved at its relative deformation λ = 0.36 and the presence of particles of different sizes (diameters) in the total volume of the rock layer (before compression). At the minimum value of the compaction coefficient kс=1.14, which corresponds to the small fraction of the crushed rock, the relative change of the void is 1.5%. For a large fraction of crushed rock at kс=1.43, the relative change in voids is 6.2%. This situation is associated with the destruction of rock particles and the reduction of voids between them. Compliance with certain requirements for backfill materials made of crushed rock, taking into account its particle size distribution, increases the efficiency of using the backfill of the excavated space. It is advisable to evaluate the bearing capacity of backfill materials by the value of the compaction coefficient of crushed rock. Scientific novelty. A functional relationship between the change in the specific potential strain energy and the relative deformation of the rock layer has been established, which allows us to estimate the degree of compaction of crushed rock under compression. Practical significance. To ensure maximum compaction of the crushed rock when using partial or complete backfilling of the worked-out space used for the protection of mine workings, it is advisable to use a heterogeneous (in terms of particle size) source material. Keywords: crushed rock, backfill material, stiffness, particle size distribution, compaction, deformation, compression.

An Evaluation of Treatment Effectiveness for Reclaimed Coral Sand Foundation in the South China Sea

Mega land reclamation projects have been carried out on the coral reefs in the South China Sea. Coral sand was used as a backfill material through hydraulic filling, with fill heights ranging from 6 to 10 m. To enhance foundation stability, vibro-flotation and impact rolling have been employed. However, the uneven distribution of coral sand, irregular particle shape, lower single-particle strength, and paucity of engineering cases for reference have posed challenges in evaluating the effectiveness of these foundation treatments. In this study, the effectiveness of vibro-flotation and impact rolling on the densification and bearing capacity of coral sand foundations has been investigated. In situ tests, including the plate load test, California Bearing Ratio (CBR) test, density measurements, dynamic penetration test (DPT), and settlement monitoring, were conducted at four distinct zones: an untreated zone, a vibro-flotation zone at a 5 m depth, a vibro-flotation zone at a 10 m depth, and an impact rolling zone. The findings suggest that coral sand exhibits promising characteristics for foundation construction. Seepage and self-weight consolidation following land reclamation formation significantly enhance the compaction degree of the coral sand foundation, thereby meeting the requirements for areas with lower bearing capacity demands. Both vibro-flotation and impact rolling techniques could significantly enhance the foundation-bearing capacity, with marginal differences between them. Since the machinery is simple and construction speed is quick, the impact rolling method is considered to be the most efficient for the treatment of coral sand foundation. The DPT results suggest that the reinforcement effect of both vibro-flotation and impact rolling on the deep foundation is not as substantial as the surface layers. This study provides valuable insights into optimizing foundation treatments for land reclamation projects on the coral reefs.

Study on effects of TiO2 Nano particles on properties of concrete

Civil Engineering is one of the vast specializations that required an advanced research to utilize the current trend in Nano technology especially utilizing eco-friendly Nano materials for various constructions such as roads, building, soil stabilization and backfill material treatment. Nanomaterials enhance the strength, durability against aggressive chemical compounds and elements that extend the effective service life of the structure. Nanomaterials can also help to reduce the need for raw materials for upkeep and repair. In particular for heavy-duty applications, Nano materials are crucial in the development of high-strength and low-energy buildings. The outcomes of laboratory and field experiments on the effects of Nano materials on the environment are also thoroughly analyzed. There are many different types of Nano particles accessible nowadays, but TiO2 was chosen for this investigation. There are several civil engineering applications for this, to investigate how mechanical properties (compressive strength and flexure strength) are affected by TiO2 Nano particles (NT). In this investigation, M30grade concrete with TiO2 at 0.2, 0.4, 0.6, and 0.8 percent by adding to the weight of cement was used.

Study of fresh properties of cemented paste backfill material with ternary cement blends

This study is aimed at evaluating the effects of ternary blended Portland cement type I (PCI) with slag and limestone (LS) powder on key engineering fresh properties of CPB: (i) rheological properties and (ii) setting time. CPB samples with PCI/Slag ratios of 50/50 (Group A) and 80/20 (Group B) were considered in this study. The effect of LS in the ternary mix was investigated by replacing the slag with increasing doses of LS (5, 10, and 20 wt%). The specimens were cast and cured over periods of 0, 0.25, 1, 2 and 4 h and tested for rheological properties (yield stress, viscosity). In addition, tests were performed to identify the initial and final setting time of the samples. In addition, microstructural tests, zeta potential and pH measurements, and monitoring experiments (temperature, electrical conductivity) were carried out to better comprehend the underlying mechanisms behind the observed changes in rheological behavior and setting time. The findings have shown that the replacement of slag by a higher dosage of LS in the ternary binder significantly affects the rheological properties of the studied CPB. It reduces the yield stress and increases the viscosity of CPB. The effect of LS on the rheological properties of CPB is mainly attributed to the physical (e.g., filler effect, lubrication, particle size) and chemical (nucleation and changes in repulsive forces between CPB particles) effects of LS in the ternary system. The findings also revealed that increasing the proportion of limestone in the CPB ternary binder system prolonged the setting time (initial and final) of the CPB mixture due to the nucleation and dilution effects of LS. Overall, the synergy between slag and LS was observed; the optimal use of LS and slag in the ternary system can serve as a sustainable alternative to the predominantly used ordinary Portland cement (OPC) or OPC/Slag binary binder, thereby reducing the energy consumption and carbon footprint associated with cement and CPB technology. The results of this research will be valuable for a better comprehension of the impacts of ternary binder with an increasing percentage of LS on the rheology and setting time of the CPB mix, ultimately, the efficient design of the mixing plant, especially the backfill transportation system.

Wastes in Underground Coal Mines and Their Behavior during Mine Water Level Rebound—A Review

Backfill materials of various origin and composition, abandoned machinery, oils, PCB, gallery support material and cables are the main wastes occurring in underground coal mines during the period of their abandonment. Bearing in mind that under increasing societal pressure most if not all underground coal mines are going to close sooner rather than later, it is important to understand the interactions of these waste materials with rising mine water during mine water level rebound to prevent adverse environmental effects, especially on surface and groundwater. To this end, the composition of mine water at decant points as well as the hydrogeochemical, temporal and spatial dynamics of mine water during rebound requires quantification. In the first part of this paper, an overview of waste materials in underground coal mines is presented. The second part focusses on the experiences gained in the Ruhr area, a closed underground coal mining region in western Germany, where mine water rebound has been ongoing for decades. In this regard, the mine water modeling program Boxmodell was applied during regulatory approval procedures to predict the hydrodynamics and hydrogeochemical development of the water rebound. The results of these investigations allow deep insights into the interactions of rising mine water with wastes as well as the complex chemical evolution of mine water and potentially occurring contaminants (e.g., PCB). The experiences regarding wastes in underground coal mines and the geochemical evolution of rising mine water gained in the Ruhr area can be utilized to support the planning of mine closure in currently still active underground coal mining areas worldwide.

Damage characterization and microscopic mechanism of steel slag-cemented paste backfill under uniaxial compression

The utilization of steel slag-cemented iron tailings for preparing mine backfill materials can effectively consume industrial solid waste generated from steel production and significantly reduce backfilling costs. The study analyzed the influence and mechanisms of steel slag (SS) content on the mechanical damage characterization of steel slag-cemented paste backfill (SS-CPB) through uniaxial compressive strength (UCS) tests and microscopic testing methods such as X-ray diffraction (XRD) and a scanning electron microscope (SEM). The engineering applicability and economic feasibility of the material were evaluated. The main conclusions were as follows: (1) With the increase of SS content, the strength of SS-CPB first increases and then decreases, with the highest strength observed at a 10% SS content. (2) The inclusion of SS in SS-CPB leads to higher peak strain and post-peak strength, demonstrating significant plastic deformation characteristics. (3) When the SS content increases from 30% to 60%, the Ca(OH)2 content in SS-CPB hydration products decreases by 20.2%, and internal micropores increase. (4) When the SS content reaches 30%, the damage mode of SS-CPB changes from purely splitting failure to a plastic combination of splitting and shear failure. These research findings provide a new application model for the collaborative utilization of steel slag, tailings, and other solid wastes.

Rheological and mechanical performance analysis and proportion optimization of cemented gangue backfill materials based on response surface methodology.

Cemented backfill mining is a green mining method that enhances the coal mining rate and the safety of mined-out regions. To transport the cemented gangue backfill material (CGBM) into the mined-out regions, it is essential to ensure high flowability and adequate compressive strength after hardening. Based on the response surface methodology (RSM), 29 experiments were conducted in this paper to test the yield stress and plastic viscosity of CGBM slurry. Cubic specimens with dimensions of 100mm were prepared and underwent uniaxial compression tests to obtain the compressive strength at a curing age of 28days. Quadratic polynomial regression models were established for yield stress, plastic viscosity, and compressive strength to explore the effects of fly ash content, water-cement ratio, mass concentration, and superplasticizer dosage on the properties of CGBM. Multi-objective optimization was conducted to determine the optimal material proportion of CGBM. The research results indicate that (1) the mass concentration most profoundly affected the yield stress and plastic viscosity of CGBM, and it increased with an increase in mass concentration. Fly ash content had an inverse relationship with compressive strength. Superplasticizer was found to improve the flowability and strength of CGBM. (2) The established response surface model could reflect the relationship between CGBM's material proportion and rheological and mechanical properties, and predict relevant parameters. (3) Multi-objective optimization determined the optimal proportion of CGBM to be 80% fly ash content, 54% water-cement ratio, 79% mass concentration, and 3% superplasticizer dosage. The research findings offer valuable guidance to mining backfill engineering.

Оценка направлений использования техногенных ресурсов при отработке различных видов минерального сырья

The paper reviews the issues related to closure of the Korkinsky coal mine in the Chelyabinsk Region. The authors describe the directions to utilize such man-made resources as open-pit excavation, overburden, and tailings generated during mining of coal and newly developed copper ore deposits. An assessment of possible ways to use man-made resources is provided in relation to abandonment of the worked-out Korkinsky coal mine. Backfilling with copper ore dressing tailings has been justified as the most rational way to abandon the worked-out coal strip mine. The paper describes the process of the backfill material production and its transportation to the discharge point. Backfilling of the Korkinsky coal mine with backfill material will help to solve environmental and social challenges of the region.

Experimental Study on the Cross-Scale Relationship of Cemented Backfill under the Action of an Air-Entraining Agent

Air-entraining agents have the function of optimizing pores and improving the performance of backfill. In this study, we used tailings and cement as the main raw materials and added different amounts of air-entraining agents to make backfill samples. By testing the uniaxial compressive strength (UCS) and microstructure, macro- and micro characteristics were studied. Nuclear magnetic resonance technology was used to explore pore characteristics, and fractal theory was used to quantitatively discuss the complexity of pore structure. Finally, a cross-scale relationship model between UCS and pores was established. The main conclusions are as follows: (1) Adding the appropriate amount of air-entraining agents can optimize pore structure and increase the UCS of backfill materials, which is beneficial to backfill materials. (2) The pores of backfill materials have fractal characteristics, the fractal effects of pores with different pore size ranges are different, and the air-entraining agent has a certain influence on the fractal characteristics of the pores. (3) There are inverse relationships between UCS and different pore size ranges.

Using recycled gangue to capture CO2 and prepare alkali-activated backfill paste: Adsorption and microevolution mechanisms

Gangue is a type of coal-based solid waste that can be used to prepare mine backfill and CO2 capture materials. However, the CO2 capture ability and activity of gangue are limited by its natural unreactive minerals and dense micro-structure. This study developed a novel chemical modification approach to modify recycled gangue and enhance its CO2 capture and hydration properties. Moreover, a new type of recycled gangue-based backfill paste was prepared to capture CO2. Multiple experiments were conducted to characterize the CO2 capture ability, mineral composition, and specific surface area of the modified gangue, as well as the hydration and microstructure of the alkali-activated modified gangue-based paste (ACM). The results reveal that the CO2 adsorbed ability and compressive strength of ACM can be significantly improved via acetic acid (AA) modification, and the optimum dosage of AA is 2 wt% of the gangue. At this dosage, the CO2 capture ability of gangue reaches 0.30 mmol/g, and the 3 d compressive strength of the ACM is doubled. This is because of the following reasons: 1) AA reacts with kaolinite and muscovite to generate acetate, which increases gangue activity; 2) the modification reduces the particle size and increases the specific surface area of the gangue, both of which are crucial for improving the CO2 capture capacity of the gangue. 3) More gels are generated in ACM, and the dense microstructure contributes to an increase in the compressive strength. This study develops an effective approach to improve the activity and CO2 capture ability of recycled gangue and thus provides guidance for backfill mining, recycled gangue utilization, and CO2 capture.

Mechanical properties and microstructure of SWGA-BF improved rock muck discharged from slurry shield tunnels

The waste muck discharged during shield tunneling has become the main source of urban construction waste. The modification of discharged muck from shield tunnels into roadbed materials can significantly improve resource utilization efficiency, but freeze–thaw environments can pose safety hazards. In this study, solid waste gelling agents (SWGAs) (50 % cement, 36 % blast furnace slag, 6 % calcium aluminate, 5 % semihydrate gypsum, 2 % calcium oxide, and 1 % alum) and basalt fiber (BF) were used as reinforcing materials for the waste muck discharged from the construction of slurry shield tunnels in rock formations. By conducting freeze–thaw cycle tests, unconfined compression tests, scanning electron microscopy (SEM) analysis, and image analysis by the ImageJ software, the effect of the freeze–thaw environment on the mechanical properties and microstructure of the improved tunnel muck by SWGA-BF composite was studied. The results show that the damage to the unconfined compressive strength (UCS) of the SWGA-BF improved tunnel muck caused by freeze–thaw cycling can be divided into three stages: rapid damage stage, slow damage stage, and basically stable stage, corresponding to N = 0 ∼ 3, N = 3 ∼ 9 and N > 9, and the damage degree generated by freeze–thaw cycle in each stage is 33.9 %, 16.7 %, and 5.0 %, respectively. The first freeze–thaw cycle causes the greatest damage. The variation characteristics of the elastic modulus of improved tunnel muck were similar to those of UCS, and the value of elastic modulus is linearly related to the UCS. The optimal content of BF is 0.5 %. As the fiber content increases, the yield strain and failure strain increase in a wavy manner. SEM tests reveal that the freeze–thaw environment increases the pore area, the size, and the number of fissures of the improved tunnel muck. However, after 12 freeze–thaw cycles, the particle diameter and abundance decreased by 20.46 % and 4.89 %, indicating that the freeze–thaw cycle effect has a greater impact on particle diameter than particle abundance. The deterioration of the microstructure eventually decreased the macro tunnel muck strength. These results have important reference values for the reutilization of waste muck discharged from shield tunneling for roadbed backfill materials in seasonally frozen areas.

Carbonation curing of modified magnesium-coal based solid waste backfill material for CO2 sequestration

CO2 sequestration is an effective method for dealing with the global climate crisis, and carbonation curing is considered an effective method of sequestering CO2 and improving the mechanical properties of cement-based materials (CBM). Regarding modified magnesium-coal based solid waste backfill material (MB), to explore its carbonation curing performance and CO2 sequestration capacity, its uniaxial compression strength (UCS), carbonation depth, microstructure, CO2 transport performance, CO2 uptake capacity, and carbonation efficiency are analyzed and characterized using UCS tests, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) analysis. The results show that the early UCS of the MB is significantly improved by carbonation curing. The UCS at 7 days is 10.91 times higher than that of the MB without carbonation curing, and the UCS increases as the concentration and modified magnesium slag-based cementitious material (MC) content increase. Carbonation curing makes the microstructure of the MB significantly denser and reduces the porosity, pore diameter, and permeability. The formation of carbonated products such as calcium carbonate and hydration products makes the microstructure more compact, which is the main reason for the rapid increase in the early UCS of the MB. The maximum CO2 uptake capacity of the MB through carbonation curing is 14.3%, and the carbonation efficiency is up to 92.2%. Therefore, carbonation curing of MB has broad application potential in improving the UCS and sequestering CO2.