High Early Strength Research Articles

Bonding performance and construction parameters of low-rebound shotcrete

Abstract Shotcrete has the advantages of short setting time, high early strength, simple process and flexible operation methods. It is mainly used as temporary support in domestic highway tunnels. This study investigates the development of low-rebound shotcrete for tunnel construction by adding silica fume and fly ash into the mixture. Sandstone and limestone were employed to simulate the surrounding rock. The workability and mechanical properties of the shotcrete were evaluated based on slump tests, rebound rates, compressive strength measurements, and bonding strength tests between the surrounding rock and the shotcrete. Furthermore, the research investigated construction techniques, with an emphasis on spraying distance, shrinkage angle, and wind pressure, and optimized these parameters for practical engineering uses. The outcomes demonstrate that the addition of silica fume enhances the mechanical properties of the shotcrete and reduces rebound. It was discovered that optimal spraying distance was between 1.2 m and 1.5 m, with the optimal wind pressure at 0.5 m, and the ideal shrinkage angle at 6°.Research on low rebound shotcrete is of great significance for improving construction quality, construction efficiency and engineering structural performance, and also meets the requirements of sustainable development.

Performance evaluation of high early strength micro-expansion geopolymer grout potentially used for sustainable road infrastructure

This study aimed to develop a high early strength micro-expansion geopolymer grout material derived from recycled concrete and ground granulated blast-furnace slag (GGBS), which can be used to fill the subgrade voids and strengthen weak subgrade. A series of grout materials with varying proportions of recycled concrete were prepared, and their setting time, flowability, and strength characteristics were evaluated. The results indicated that the grout material containing 50 % recycled concrete had a final setting time of 29 min, a flow time of 15.2 s, and a 7-day compressive strength of 40.6 MPa, all of which met the requirements for subgrade grout materials. To further enhance the performance of the grout, the additives including 2 % calcium chloride (CaCl2), 5 % magnesium oxide (MgO), and 5 % united expansive agent (UEA) were used. Results showed that the samples containing 50 % recycled concrete and 2 % CaCl2 exhibited a 26.5 % increase in strength after 100 min of curing, while MgO and UEA reduced shrinkage by 112.5 % and 90.0 %, respectively. Additionally, microstructural analysis using SEM and XRD provided valuable insights into the complex interactions between components and their effects on material integrity. The results demonstrated that the use of CaCl2 accelerated the hydration reaction, enhancing early strength, while the expansion agents MgO and UEA mitigated shrinkage and achieved micro-expansion at low concrete content. This study addresses environmental concerns by incorporating recycled materials, positioning the developed geopolymer grout as a sustainable, high-performance alternative in road construction. Integrating waste-derived components and innovative additives represents a significant step towards advancing sustainable practices in infrastructure development.

Development of geopolymer and cement-based shotcrete mortar: Impact of mix design parameters and spraying process

Shotcrete mortar is used in various construction works, including repair, tunneling, mining, and slope stabilization, among others. Traditionally, cement is used to produce shotcrete mortars with high viscosity, flowability, and early strength. Geopolymers (GP) have the potential to replace cement in shotcrete mortars, owing to their ability to reduce the material’s environmental footprint without compromising performance. This investigation assesses the feasibility of utilizing fly ash and blast furnace slag-based GP mortars produced with dune sand in shotcrete applications while comparing them to cement-based mixtures. The GP and cement-based shotcrete mortars were designed to have similar yield stress values. The evaluated properties included the initial flow, thickness layer, rebound material, rheological properties, setting time, compressive strength, ultrasonic pulse velocity, and pull-off bonding strength. Test results showed direct relationships between the yield stress and initial flow values, as well as between the buildup thickness and plastic viscosity, revealing that GP mortars were suitable for shotcrete applications, specifically those produced with flow values of 18.5 cm or less. GP mixtures produced with higher slag content than fly ash, higher sand content compared to binder, higher SH molarity, and lower solution content achieved higher buildup thickness owing to their higher viscosity. In the second phase, the performance of four mixes with different initial flows was assessed at various pumping flow rates and distances between the wall and machine pipe nozzle. The findings confirmed that these spraying parameters are crucial to improve the shotcrete performance of GP mortar with varying fresh behaviors.

Effect of synthetic C-S-H seeds on hydration process, mechanical properties and microstructure of seashell powder calcined sludge cement

Seashell powder calcined sludge cement (SCSC) is a new type of green low-carbon ternary cement prepared by using waste sludge and waste seashells. It reduces carbon emissions in the cement production industry and solves environmental problems such as serious soil-water-air pollution caused by long-term stockpiling of waste sludge and waste seashells, which are difficult to be utilized in a resourceful manner. However, the reduced clinker content results in lower early strength of SCSC, which limits the application of SCSC in applications requiring high early strength such as precast concrete specimens. In this paper, the effects of different dosage of C-S-H seeds on the hydration process, mechanical properties and microstructure of SCSC slurries were investigated. The results showed that C-S-H seeds significantly increased the 12-hour compressive strength of SCSC, and the 2 % addition of C-S-H seeds increased its compressive strength by 271 %, but had less effect on its later strength. The proportion of large pores in the sample with a 1 % addition of C-S-H seeds decreased by 1 %. At 12 hours, 2 % addition of C-S-H seeds increased its total hydration exotherm by 141 %. The addition of C-S-H seeds decreased the fluidity of the slurry but did not change the flow pattern of the slurry. The relationship between the rheological parameters of the slurry and the addition of C-S-H seeds was well fitted with a primary function, and the rheological equations of SCSC slurries with different additions of C-S-H seeds were obtained. The results of this paper can further broaden the application scenarios of SCSC and lay the foundation for the large-scale application of SCSC.

Chloride permeation resistance of sulphoaluminate cement-based composite characterized by both alternating current section and RCM methods

Sulphoaluminate cement (SAC) was widely used for rapid repair and strengthening of building structures due to its excellent quick hardening and high early strength behavior. This study developed a SAC-based engineering cement composites (ECC) with ultra-high molecular weight polyethylene (UHMWPE) and investigated its mechanical properties. Chloride ion permeability coefficient were evaluated by new alternating-current sectioning and rapid chloride migration (RCM). The mechanism of the SAC-ECC against chloride erosion were quantified using nitrogen isothermal adsorption. The results show that the fracture energy, tensile strength and strain of SAC-ECC samples are higher than that of normal ECC. The polyethylene (PE) fiber could significantly improve the flexural strength and toughness with PE fiber content of 0.75 % by volume. The hydration products generated could react with chloride ion to make it chemically stabilized, leading to reduce the chloride ion diffusion coefficient significantly. Based on microscopic analysis (SEM), the pore structure in SAC-ECC composite improved remarkedly while the volume of harmful pore decreased evidently as well. SAC-ECC developed in this paper could be poetically applied to strengthening and repair of marine concrete structures.

Optimal development and performance evaluation of electrolytic graphene oxide synergistic all-solid waste cementitious grouting material

The low-carbon and friendly alkali-activated cementitious (AACM) grouting material has a broad application potential in the field of grouting engineering due to its excellent workability and higher early strength and is expected to replace cement grouting material in the future. In this study, an AACM grouting material using electrolytic graphene oxide (EGO) synergistic ground granulated blast-furnace slag (GGBS)-fly ash (FA)-rice husk ash (RHA) solid waste was proposed. The optimal ratio was 0.025 % EGO, 8.13 % FA, 26.6 % RHA, and 65.27 % GGBS, which determined by the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWP), and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods. A systematic evaluation of the mechanical properties and impermeability of the proposed AACM grouting material was conducted by macro experiments (compressive strength, flexural strength and permeability) and micro experiments (XRD, SEM-EDS, Fourier Transform Infrared Spectrometer (FTIR) and Thermogravimetry Analysis (TG)). The results show that the increment of compressive strength and flexural strength for AACM grouting material with 0.025 % EGO compared to the cement water-glass grouting material were 161.2 % and 2.9 %, respectively, at 7-day. While the permeability coefficient compared to AACM grouting material without EGO decreased by 43.9 %. The XRD results show that the EGO reduced the intensity of AACM grouting material diffraction peaks, and FTIR analysis reveals that EGO increased the visibility of O-C-O characteristic peaks. These confirmed that EGO could enhance the degree of alkali activation reaction. The TG results indicate that the addition of EGO promoted the formation of carbonates, which strengthen the mechanical properties of AACM grouting material. The SEM-EDS results demonstrate that EGO increased the Ca/Si ratio, promoted the formation of highly polymerized hydration products.

Development of binders based on the СаО–Fe2O3 system

The object of research is the processes of structure formation and modeling of the properties of a specialized binder. The development of new binding materials based on production waste with high early strength indicators could make it possible to speed up construction period and is one of the urgent tasks at present. This study focused on the creation of binders based on the СаО–Fe2O3 system. The developed binder of the СаО–Fe2O3 system has the following composition: limestone – 26 %; red slime – 74 %, which has a dense fine-porous structure and high early strength indicators – 22.5 MPa with a density of 1960 kg/m3. There is also an increase in the average density of samples annealed at a temperature of 1200 ℃ for 60 minutes, ground and mixed with water, in comparison with samples fired at 1100 ℃ for 60 minutes, by 500 kg/m3, due to new formations. The prospect of using modified composite binders with special functional properties has been substantiated. The use of production waste based on the СаО-Fe2O3 system could make it possible to obtain materials with high physical and mechanical properties, which makes them promising for application in various areas of the construction industry. The development of such binders will help reduce the environmental impact of the construction industry, owing to the use of affordable and effective components. This approach will not only contribute to the improvement of the quality of building materials but also help reduce the ecological burden on the environment by using alternative resources and industrial waste. The developed binder could be used for the development of solutions for 3d printing, as well as repair of concrete coatings

Research on the effect of tuff powder on the properties of moderate-heat portland cement-based materials and the methods for evaluating pozzolanic activity

Tuff powder (TP) has attracted significant attention due to its abundant resources, low carbon emissions, and potential enhancements in concrete property. This study investigates the effect of TP on the mechanical properties, hydration behavior, pore structure, microstructure morphology, economic and environmental analysis of moderate-heat portland cement (MHPC), comparing it with MHPC-based materials containing fly ash (FA). The synergistic morphological effect and micro-aggregate filling action of FA and TP result in higher early strength in the fly ash-tuff powder (FT) group mortar. The CH content and chemically bounded water content of TP paste are higher, showing a better early hydration promotion effect. The pore structure of the composite cement mortar is changed due to the addition of the admixture. Furthermore, the multi-factor response strength and strength activity index (SAI) model were developed based on response surface methodology (RSM), linking to TP specific surface area, dosage, and specimen curing age. This provides a reference for more accurate and comprehensive prediction of cement mortar property, quantification of effects, optimization of mix proportions, and evaluation methods for the activity of pozzolanic materials.

Characterization and Properties of Binder and Nano-Filler in Geopolymer Paste with Graphene Oxide

Globally, current research has developed new cement-based materials to meet increased demands for performance, energy efficiency, and environmental protection. Geopolymer, cost-effective, and high-early strength concrete binder alternative, has grown in popularity. Geopolymer reduces emissions by 80% during production while maintaining strength levels comparable to Ordinary Portland Cement (OPC). In their natural state, geopolymer binders have a microstructure that is cross-linked and significantly more brittle than OPC. To improve the properties of geopolymer, several approaches were adopted. However, recent study suggests that incorporating nanomaterials such as graphene oxide (GO) to geopolymer has shown an improvement in physical and mechanical properties. Graphene oxide is an inorganic nanomaterial that improves the mechanical characteristics of various composite materials by showing substantial filling effects on composite materials that significantly improve composite material integrity. The investigation into the potential of GO to improve the efficacy of geopolymer composite materials in various engineering applications has garnered considerable attention in recent years. The simplified hummer’s method was employed to synthesise the GO. Various characterization techniques involving SEM, XRD, and FTIR were utilized to understand the crystalline structure and microstructure of GO nanoparticles. GO powder were used as 0.05%, 0.10%, 0.15%, 0.20%, and 0.25% by weight of binder that includes fly ash class F and steel slag with an optimum binder modification of 40% fly ash and 60% steel slag. The influence of GO on Bulk density, microstructure, and mechanical strength were determined. The compressive strength results indicated an improvement of compressive strength by 21.48% in geopolymer paste with 0.15% GO after 28 days of curing.

Combined effect of supplementary cementitious materials and hot-dipped galvanized steel on performance of reinforced concretes subjected to chloride-induced corrosion

Concrete specimens with three types of cement (sulfate resistant high early strength – reference, pozzolanic, and with ground granulated blast furnace slag) reinforced with two types of steel (galvanized and carbon steel) were subjected to cycles of immersion in 1.0 M NaCl solution and drying at 40ºC. For each different steel-concrete condition, 6 rebars were tested. Experimental results show that galvanized steel presents longer corrosion initiation periods in concretes with supplementary cementitious materials. Particularly for pozzolanic concrete, this increased initiation period was 4.6 times longer on average, which reflects, in a similar way, on service-life simulations. In general, the average chloride thresholds of galvanized steel increased with a decrease in pore solution alkalinity. Compared to carbon steel, higher chloride thresholds were found for galvanized steel embedded in the lower alkalinity concrete matrix (calculated pore pH = 12.6). On the other hand, galvanized steel presented lower chloride thresholds for more alkaline pore pHs (pozzolanic and reference concretes).

Synergizing metakaolin and waste-glass for sustainable and functional UHPCC– a central composite design and ecological footprint assessment

Optimizing ultra-high-performance cementitious composites (UHPCC) with sustainable materials often compromises certain properties due to the chemical nature of alternative binders used to replace standard UHPCC components like Portland cement (OPC) and microsilica (MS). In the context of Waste-Glass-UHPCC, the reduction in early strength, attributed to the varied pozzolanic reactivity of MS and recycled glass powder as cementitious materials, may reduce its application that requires high early strength. This study addresses the early strength deficiency of Waste-Glass-UHPCC by incorporating metakaolin (MK) and also aims to assess the impact of MK on 28-day compressive strength, durability, and carbon footprint. Research investigating the effects of MK on UHPCC with reduced OPC and MS content is currently limited. Specifically, this investigation explores the influence of MK on UHPCC characterized by a cement content of 620 kg/m3. By utilizing advanced statistical methods [i.e., the Central Composite Design (CCD) and Response Surface Methodology (RSM)], this study investigates the substitution of MK for OPC in formulations of Waste-Glass-UHPCC. The experimental design comprises 18 encoded mixtures, allowing for the development of second-order regression models for critical responses [slump flow and compressive strength at different ages]. Besides, visualization through RSM-3D graphs facilitates a comprehensive examination of the effects of various factors. For a deeper analysis, two of the CCD's points, i.e., SP-12 (Waste-Glass-UHPCC without metakaolin), and SP-10 (Waste-Glass-UHPCC with 65.77 kg of metakaolin per cubic meter) were further investigated along with a control dosage that represents a typical UHPCC formulation. The responses studied encompassed 1, 7, and 28 d compressive strength, chloride ion penetration, and carbon footprint measured by a systematic life cycle analysis (following ISO 15804), assessing the environmental impact of the UHPCC's making materials from raw extraction to disposal. Despite encountering challenges in meeting self-compacting concrete criteria due to MK's tendency to accelerate hydration, the enhanced early strength properties (61 % higher than those of the Waste-Glass-UHPCC) make the MK-based mixture appropriate for various applications such as bridge engineering or pavement rehabilitation. Additionally, the addition of MK in UHPCC formulation demonstrated superior resistance to chloride ion permeability even compared to the control mixture, attributed to MK's ability to enhance the concrete's microstructure and capture chloride ions, attributed to Friedel's salt formation. Noteworthy findings include a significant (27 %) reduction in carbon footprint with the incorporation of MK in Waste-Glass-UHPCC compared to the control counterparts. The current study highlights the durability and environmental advantages of MK-based UHPCC blends while emphasizing the critical requirements of workability and strength development of sustainable UHPCC.

Experimental study of bond behavior of geopolymer concrete under different curing condition using a pull-out test

Researchers recently have focused on geopolymer concrete as it has several advantages compared to traditional Portland cement, such as lower carbon footprint, high early strength, chemical resistance and long-lasting structural performance. This paper designed 192 pull-out specimens to investigate the influence of factors on the bond-slip behavior between geopolymer and steel bar such as curing condition (ambient and 80 °C for 7 hours), longitudinal rib angle, the position of longitudinal bar, bar diameter (12 mm and 24 mm), stirrup usage (with and without stirrup) and bond length (2d and 4d). The maximum bond strength, bond failure modes, and bond stress-slip relations were discussed. The test results showed that the longitudinal rib angle, and the position of rebar play a vital role in determining the bond strength as well as the bar diameter. In comparison with the specimens without the stirrup, the bond performance of specimens with stirrup increased more significantly, and this phenomenon became even more pronounced as the bar diameter increased. The stirrup usage in samples under ambient and heat cure increased the bond strength by an average of 45 % and %40, respectively. Moreover, it has been determined that the curing conditions have a significant effect on the bond performance, as especially the compressive and tensile strengths of the samples under heat cure improve. In samples exposed to both ambient and heat cure, doubling the bond length increased the bond strength by 70 %. Furthermore, increasing the bar diameter increased the bond strength of the samples exposed to ambient and heat curing by a maximum of 84 % and 79 %, respectively. The findings lay the groundwork for understanding the bond behavior of geopolymer, which is critical for the successful application of geopolymer-bonded rebar.

Optimization of mechanical property and microstructure for magnesium phosphate cement-based canvas using borax

As a type of excellent rapid protective material with fast hardening and high early strength characteristics, magnesium phosphate cement (MPC) is used as the cementitious material to fabricate concrete canvas. For a thick MPC canvas, sufficient hydration reaction is crucial in keeping its integrity. Borax is used to adjust the hydration progress of MPC in warp-knitted fabrics. The effects of different borax contents (0 %, 1 %, 2 %, 3 %, 4 %, 5 %, 6 %) on the compactness of reaction products and the mechanical properties of MPC canvas are evaluated. In addition, SEM, XRD, hydration heat, and X-CT are used to systematically analyze the hydration morphology, products, exothermic process, and pore structure of MPC canvas. The results show that borax can effectively delay the setting time of MPC, addressing the issue of incomplete hydration of MPC powder in thick canvas. The 4 % borax content (B4 sample) can ensure the complete reaction in a 20 mm thick MPC canvas, achieving the maximum compressive and flexural strengths of 26.37 MPa and 4.9 MPa at 7 d, respectively. Borax effectively optimizes the pore structure of MPC canvas and achieves a dense bond at the interface between MPC and the canvas fabric with the minimum porosity of 11 % in the B4 sample. Therefore, borax is crucial for ensuring the structural integrity of MPC canvas.

Nucleation and growth rate determination on alkali-activated slag under various sodium hydroxide molarity

Alkali-activated slag has been noted as one of potential alternatives to the ordinary Portland cement due to its properties including high early strength performance and capability of ambient curing. However, there is still limited studies available on elucidating the reaction processes towards producing the excellent properties. This study aims to elucidate the mechanism of alkali activation of slag under different molarities of sodium hydroxide, which is one of the most influential factors on the properties of alkali-activated slag. Heat evolution of alkali-activated slag was used as a real-time monitoring technique. For mix designation, the molarity of sodium hydroxide was varied from 6M to 14 M, with solid-to-liquid ratios of 0.6 and alkali activator ratios of 2.0 remaining constant. The calorimetric data obtained was further used for determination of degree of reaction, nucleation and growth rate mechanism using Johnson–Mehl Avrami Kolmogrov model. According to the findings, it was found that regardless of various molarity of sodium hydroxide applied, the nucleation mechanism and growth is governed by instantaneous heterogeneous nucleation with rod-like growth as the n value is approaching 1 in which is observed from the morphology of the alkali-activated slag at lowest molarity applied (6 M). Furthermore, increasing in molarity of sodium hydroxide was found to decrease the total heat evolved and the lowest was obtained when using 14 M.

Strength evolution and microstructure of alkali-activated ultra-fine slag in low-temperature environments

At low temperatures, the hydration rate of Portland cement significantly slows down, resulting in a decrease in its strength. Additionally, the pore solution freezes easily. As a kind of low-carbon cementitious material, alkali-activated slag (AAS) material has a short setting time at room temperature and a high early strength, meanwhile the alkali solution does not freeze at low temperatures. This study investigates the evolution mechanism of the strength and microstructure of AAS pastes cured at 0℃. Slag with different fineness was activated by a sodium silicate solution with different moduli, whose strength was compared with that of an AAS paste cured at 20 °C. The setting time, compressive strength, hydration process, pore structure, freezing point, and microstructure of the AAS paste were studied, whose results showed that the setting time of the AAS paste was obviously prolonged, and the compressive strength decreased under low-temperature curing. After the activation of slag ground, the early compressive strength of the AAS paste was significantly improved, whose reason was that the hydration degree of the paste was improved after slag ground, and that a dense pore structure was formed. The freezing point of the AAS paste was approximately −26 °C, which, remarkably, even at −40 °C, was still capable of undergoing a weak chemical reaction, producing an exothermic enthalpy. This characteristic makes alkali-activated ultrafine slag a highiy-promising cementitious material for curing at low temperatures.

Chitosan-Cement Composite Mortars: Exploring Interactions, Structural Evolution, Environmental Footprint and Mechanical Performance.

The increasing environmental concerns about synthetic polymers as reinforcement in the construction industry have highlighted the need for eco-friendly, biodegradable fibers as potential alternative materials for cementitious composites. This study examines the influence of chitosan particle concentrations on the midterm compressive strength of mortars. Chitosan particles, derived from shrimp shells, were mixed with high early strength hydraulic cement at various percentages (0, 0.05, 0.25, 0.5, 1, and 2 wt %) and silica sand to prepare the mortar samples. The findings indicate that chitosan affects the hydration process through the distribution of chitosan particles within the mortar matrix and slightly improved midterm mechanical properties. A life cycle assessment (LCA) revealed a slight increase in greenhouse gas emissions and embodied energy for chitosan-modified mortars, likely due to the use of chemicals in the chitosan synthesis and purification process. In fact, the addition of 0.25 wt % of chitosan into the mortar only added 1.3% of the global warming potential of the sample when compared to the control sample. Incorporating chitosan into a mortar matrix does not significantly affect the resistance-mechanical properties of the composite. The hydration of the cement mortar appears to be slowed by the inclusion of chitosan particles in the cementitious matrix. This research lays the groundwork as one of the first studies for the development of high-performance, early strength cement using chitosan, contributing to a more sustainable construction industry.

Effective function of activated bagasse ash for high early strength geopolymer

Effective function of activated bagasse ash for high early strength geopolymer

The influence of accelerators on compressive strength and setting time of cement to achieve high early strength for 3D concrete printing technology

The development of 3D concrete printing (3DCP) technology has completely changed the way that complicated structures are built, it also increases efficiency and lowers costs. Achieving high early setting and early strength in 3DPC are still a considerable difficulty. This study examines the impact of accelerators on the setting time of rapid hardening pozzolana cement. Sodium hydroxide (NaOH), Calcium Chloride (CaCl2), Calcium nitrite (CN), Triethanolamine (TEA), triisopropanolamine (TIPA) were used as an accelerator for this study. The findings show that the addition of accelerators reduces the setting time significantly while also increasing the compressive strength. With the help of the findings, mixed design parameters for 3DCP technology can be optimized, allowing for the rapid curing of durable structures. The practical application and widespread acceptance of 3DCP technology in the construction industry are affected by these findings.

Fly ash-GGBS blended geopolymer mortar for early engineering characteristic at ambient temperature

Geopolymer concept is by using industrial waste materials which is rich in silica and alumina, then activating them with alkaline solution. An appropriate binder combination that achieves high early age strength at ambient temperature using FA is still subject required. Thus, this study has been designed in two stages which involving the paste and mortar studies. The alkaline activator as a blend of sodium hydroxide and sodium silicate solution with SS/SH ratio of 2.5, NaOH molarity of 12 M and L/B ratio of 0.43 are used for geopolymer composite. Compressive strength, water absorption and shrinkage are tested on geopolymer mortar with various level of blended combination. High volume content (60–80 %) gave a promising early age compressive strength at ambient temperature. Metakaolin gave a further strength improvement on geopolymer mortar. Overall, the finding suggested that the geopolymer with high FA content is suitable for cement-based material repair product.

Utilization of red mud in high-performance grouting material for semi-flexible pavement

The huge amount of red mud has brought great challenges to the sustainability of global economic development. Red mud, a solid waste, causes resource wastage and environmental pollution, even endangering human health. A technology used to overcome such a situation involves broad-scale recycling of red mud in road engineering. In this study, Bayer red mud is utilized as a high-performance grouting material for semi-flexible pavement (SFP). A series of sensitivity analyses are performed using macroscale testing to determine the optimal amount of red mud and water-cement ratio for red mud-based cementitious materials (RCM) grouting material. This includes alkali-activated “red mud-slag powder” binary cementitious material (RSCM) and non-alkali-activated “red mud-cement” cementitious material (RCCM). Additionally, the hydration process and products of RCM are analyzed using microscale testing, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The results of the analysis indicate that red mud has significant potential for recycling as SFP materials to achieve the goal of high fluidity and early strength. The workability and early strength of RCCM are even higher than those of cement, indicating that part of the cement can be replaced by red mud. Moreover, the macroscale conclusions of RCM can be confirmed by microscale testing. These low-carbon grouting materials offer the added advantages of recycling waste that would otherwise be destined for landfill, along with reducing the carbon footprint and economic impact associated with cement production.