Rapid-repair of concrete pavements is crucial for minimizing traffic disruptions and restoring serviceability in time-crucial situations. While Portland-based and alternative rapid-hardening binders are frequently used, these materials often trade off between cost, durability, and environmental concerns. This systematic review explores the potential of AAMs as a sustainable alternative for rapid pavement repair, with particular emphasis on early-age performance and the reliability of maturity methods for non-destructive strength monitoring. Adhering to PRISMA guidelines, this study screened the published literature from 2000 to 2025 using PICO(S) criteria, focusing on AAM interventions for rapid pavement repair and comparing them with conventional and alternative binders where applicable. The review correlates precursor-activator systems with early mechanical performance and assesses the applicability of maturity-based approaches for predicting in-situ strength development. The findings indicate that optimized slag-containing AAMs achieved compressive strengths of about 16–28 MPa within 6–8 h, offering superior bonding and durability. Additionally, maturity methods demonstrate strong potential for real-time strength prediction; however, their distinct and complex non-linear reaction kinetics necessitate the rigorous, system-specific recalibration of key thermodynamic parameters. Despite these advantages, persistent challenges remain, including high sensitivity to activator chemistry and curing conditions, poor volumetric stability, supply chain and economic uncertainties, and a critical lack of standardized testing and long-term field data. This review affirms that integrating optimized AAM formulations with maturity-based prediction tools provides a high-performance, low-carbon pathway for accelerating repair operations. To support reliable performance-based decisions for early traffic reopening, future research should adopt a multi-scale, lifecycle-oriented framework that connects materials design, structural performance, and long-term field validation.
This study systematically investigates the effects of varying steel fiber contents on both mechanical and electromagnetic shielding properties of Carbon Black cement mortar. Comprehensive evaluations were conducted, including flexural strength and compressive strength measurements, electrical conductivity tests, and electromagnetic shielding performance simulations across the 1–18 GHz frequency range. The experimental results demonstrate that steel fiber incorporation significantly enhances flexural strength (maximum 10.6 MPa, 22.3% improvement), compressive strength (peak 56.1 MPa, 32.3% increase), and electrical conductivity (optimal 37.8 mS/m, 517.64% enhancement). However, due to the random orientation and distribution characteristics of steel fibers, no consistent correlation between fiber content and conductivity was established. Regarding electromagnetic shielding performance, a progressive improvement was observed with increasing steel fiber content. The composite exhibited an average shielding effectiveness of 14.93 dB at the optimal fiber dosage of 200 kg/m3, while achieving a maximum total shielding effectiveness of 27.25 dB (814% enhancement) at 18 GHz.
Granulated blast furnace slag (GBFS) is an industrial by-product with high latent activity generated during pig iron smelting, and its unique vitreous structure results in poor grindability. Therefore, activating the latent activity and improving the grindability of GBFS have become research hotspots in the relevant field. In this study, a low-molecular-weight polymer was synthesized using 2-acrylamido-2-methylpropanesulfonic acid (AMPS), hydroxypropyl acrylate (HPA) and diethylene glycol monovinyl ether (DEGVE) as polymerizable monomers, and then compounded with polyhydric alcohol to prepare a polymer grinding aid suitable for GBFS. The effects of the polymer grinding aid on grinding efficiency and hydration properties of GBFS-blended cement paste were systematically investigated. The results showed that the particle size of GBFS ground with the polymer grinding aid was slightly coarser than that of the alkanolamine-treated sample. But the polymer grinding aid could optimize the cross-linked structure of hydration products and improve the early age and long-term strengths of GBFS-blended cement. When the dosages of initiator and chain transfer agent accounted for 1.28% and 5.14% of the total monomer mass, respectively, and the monomer molar ratio satisfied n (DEGVE):n (AMPS):n (HPA) = 1:2.65:0.5, the obtained polymer grinding aid provides a better balance between particle-size distribution optimization of GBFS and strength development of GBFS-blended cement, while the individual fineness parameters remain comparable to or slightly lower than the sample prepared with reference alkanolamine-based grinding aid. Compared with the alkanolamine-based grinding aids, the volume fractions of GBFS particles with particle sizes of 0–3 μm and above 64 μm treated by the polymer grinding aid decrease by 5.4% and 76.0%, respectively, while the volume fraction of particles with particle sizes of 32–64 μm increases by 12.2%. Correspondingly, the 7 d and 28 d compressive strengths of the GBFS-based cementitious materials are increased by 8.4% and 4.3%, respectively.
Converting solid waste into building materials is the most effective large-scale solution for industrial by-products, yet the high impurity content and unstable properties of phosphogypsum (PG) hinder its widespread use. This research examines the influence of three activators—waterglass (WG), sodium aluminate (SA), and calcined phosphogypsum (CPG)—on the properties of phosphogypsum foam concrete (PFC). The Krstulovic-Dabic model was employed to unravel the hydration kinetics of PFC. FTIR and low-field nuclear magnetic resonance were used to investigate the hydration products and pore structure. The results reveal that the optimal proportions are 1% for WG, 0.4% for SA, and 20% for CPG, respectively, with the SA-0.4% group showing the highest 28 d compressive strength. This improvement stems from notable enhancements in the nucleation and crystal growth stage of reaction kinetics, according to the Krstulovic-Dabic model. Hence, incorporating SA can maximally promote the hydration reactions. The generated hydration products can fill the micropores and separate them into smaller transition pores. This reduces the proportion of interconnected pores and refines the pore structure of PFC. As compared with the control sample, the porosity of SA-0.4% PFC decreases by 11.8%. This research provides theoretical support for utilizing PFC to prepare high-performance PFC and to realize sustainable development in the construction field.
Magnesium potassium phosphate cement (MKPC) exhibits strength degradation and volume shrinkage under high-temperature conditions, which hinders its application in high-temperature scenarios. The effects of aluminium hydroxide (AH) and basalt fiber (BF) on the room-temperature properties and high-temperature resistance of MKPC were investigated using XRD, SEM, and EDS. The strength results showed that incorporating 15% aluminium hydroxide increases the residual strength of MKPC by 48.87% to 101.59% following heat treatment at 200~1100°C. The presence of basalt fibers reduced the volumetric changes of MKPC after heat treatment, but led to a decrease in the residual strength. The microstructural test results showed that aluminium hydroxide markedly promoted the formation of refractory phases, including α-active alumina and magnesium aluminate spinel, at high temperatures, whereas debonding was observed in specimens incorporating basalt fibers. Based on the above experimental results, the coupled effects of aluminium hydroxide and basalt fibers on the high-temperature resistance of MKPC were discussed. The research findings may provide insights for the application of MKPC in high-temperature scenarios.
This study aims to investigate the influence of amorphous silica on the mechanical properties and fire resistance of gypsum boards, as well as the water-to-gypsum ratio and setting time of gypsum. The results indicate that amorphous silica has a negligible impact on the water-to-gypsum ratio and setting time of gypsum, while it can enhance the mechanical properties and fire resistance to some extent. With the incorporation of 4 wt% amorphous silica, the breaking load of the gypsum board parallel to the long side increases from 311 N to 324 N, while the breaking load perpendicular to the long side rises from 622 N to 682 N. The edge hardness of the gypsum board increases from 116 N to 136 N, while the end hardness rises from 143 N to 165 N. In addition, the fire stability of the gypsum boards is also clearly enhanced, with the fire resistance time increasing from 326 min to approximately 520 min at 800°C. This is attributed to the filling of amorphous silica particles between gypsum crystals, which inhibits crack propagation of the gypsum board under stress. In addition, under elevated temperature conditions, amorphous silica undergoes sintering, transforms from amorphous to crystalline, compensates for shrinkage, and improves the fire resistance of the gypsum board.
This study presents a purpose-built laboratory planetary mixer designed to reproduce industrial lime hydration processes under controlled conditions. The system enables simultaneous control of key parameters such as temperature, pressure, water dosage, and mixing dynamics, allowing reproducible hydration of a wide range of materials, including quicklime, dolomitic lime, natural hydraulic lime, and cementitious by-products. Specific hydration protocols were developed to obtain targeted products, ranging from standard hydrated limes for construction applications to high-surface-area sorbents for flue gas desulfurization. The results demonstrate that hydration conditions strongly control both phase conversion and porosimetric properties, enabling the production of materials with tailored performance. Two alternative technological routes were identified to produce high-BET hydrated limes: excess-water hydration, which maximizes surface area but requires post-drying, and additive-assisted hydration, which improves phase purity and reduces residual moisture. In addition, pressure-controlled hydration promotes MgO conversion and enables the production of high-performance dolomitic sorbents. Overall, this study establishes a direct link between process parameters, hydration mechanisms, and product performance, providing a practical tool for raw material selection, process optimization, and scale-up to industrial hydrator operation.
The widespread application of alkali-activated soil-based artificial aggregates (AAs) is limited by their low early strength and high-water absorption, creating an imperative for effective enhancement methods. This study investigates the efficacy of thermal treatments (heat curing and microwave curing) and surface treatments (alkaline solution immersion, double pelletisation, and slurry immersion) in enhancing their performances. The properties of AAs were evaluated through crushing strength, water absorption, and apparent density tests, with underlying mechanisms elucidated by microstructural analyses. The results demonstrate that both heat curing and microwave curing significantly enhance the early-age strength, improving the 1-day crushing strength by over 140% and 100%, respectively. This enhancement is attributed to the accelerated formation of C-(A)-S-H gels and hydrotalcite. However, a slight increase in water absorption and a reduction in 28-day crushing strength are observed, primarily due to microcracking induced by the rapid drying process. Among the surface treatments, alkaline solution immersion and double pelletisation increase apparent density by-3.6%, reduce water absorption by-22.3%, and enhance crushing strength by-30.9%, primarily due to the formation of a denser outer shell. In contrast, slurry immersion adversely affects the properties owing to its uneven coating and potential aggregate swelling. This study provides practical strategies and mechanistic insights for optimising the performance of AAs, facilitating their industrial production and application.
A lack of microscopic mechanistic research on the interaction between ions and materials has hindered the extension of the durability of concrete in deep-sea conditions. This study utilized molecular dynamics (MD) simulations to investigate the adsorption behavior of Na+ and Cl- in ettringite and defective ettringite nanopores. The effects of ocean depth, doping ion types (Sr2+, Fe3+, and IO3-), and doping levels (2%, 10%, 15%, and 20%) on ion adsorption were analyzed. The results showed that ocean depth, doping ion types, and doping levels significantly influenced ion distribution in nanopores. While these factors did not alter the bonding mode between Na+ and anions, they significantly affected the bonding mode between Cl- and cations. Additionally, changes in depth, doping ion types, and doping levels significantly impacted ion pair stability, thereby affecting ion diffusion. The effect of doping level on ion diffusion was complex, with varying suppression or promotion effects observed on different substrates. An increase in depth across all substrates significantly inhibited ion mobility. This study provides a strategy to explore the microscopic mechanism of ioncement interaction in deep-sea environments and proposes a potential solution for improving the stability of cement-based materials in such conditions.
Bioacidic erosion from microbial activity threatens concrete infrastructure in sewage systems. This study evaluated the durability of four cementitious materials under simulated bioacid attack for 120 days. Results indicated that Ultra-High Performance Concrete (UHPC) exhibited superior resistance, with mass loss of 0.17% and compressive strength loss of 7.54%, representing reductions of 95.15% and 72.07% compared to Ordinary Portland Cement (OPC), respectively. Microstructural analysis revealed that UHPC's dense matrix (total porosity of 8.6% versus 23.86-34.13% for other materials) and ettringite formation contributed to its enhanced stability. In contrast, Alkali-Activated Slag (AAS) and Calcium Sulfoaluminate Cement (CSA) exhibited cracks and voids, indicating poor durability. The corrosion mechanisms varied among materials: UHPC resisted sulfate attack through its dense microstructure; CSA suffered from ettringite instability; AAS degraded via calcium aluminate hydrate decomposition; and OPC showed severe structural deterioration. These findings demonstrate that UHPC possesses significant potential as a high-performance protective material for sewage infrastructure applications.
This study investigates the impact of carbonation and chloride penetration on the corrosion of steel bars embedded in magnesium phosphate cement. Specimens with varying chloride concentrations (0%, 1%, 2%, and 3%) were prepared and cured under both natural and carbonation conditions. A combination of macroscopic tests and electrochemical techniques, along with microstructural analysis, was used to examine the corrosion behavior. The results show that increased chloride content weakens the corrosion protection of the steel bars, with carbonation accelerating this degradation. In natural curing conditions, corrosion began when the chloride level reached 2%, while carbonation reduced this threshold to 1%. The microstructural analysis revealed that higher chloride content caused cracks in the protective film on the steel surface, weakening the bond between the steel and the surrounding material, thus diminishing the overall protection of the reinforcement.
In this study, the effect of industrial hemp waste incorporation on cement-based mortar performance was investigated. Three forms of hemp fibers were examined: raw fibers (6 mm in length), ground fibers, and powder passing through a 2 mm sieve. These were incorporated as a partial aggregate replacement at 0.5% volumetric ratio. All mixtures were produced with a constant water-to-cement ratio of 0.52, while a polycarboxylate ether-based high-range water-reducing admixture was used to achieve the target flow value of 180 +/- 10 mm. The addition of hemp fibers adversely affected the flow performance of the mixtures, primarily due to the high water absorption capacity of the fibers, which reduced the amount of free water available in the system. It has been observed that fiber reinforcement improves the thermal conductivity performance of the mixture. Compressive and flexural strengths showed substantial reductions with fiber incorporation, particularly compressive strength. This strength reduction was associated with increased void volume from fiber agglomeration in the matrix. The ground hemp fiber (HG) mixture demonstrated the highest water absorption, while the Control mixture showed the lowest. These observations indicate that fiber incorporation may reduce mechanical performance, mainly due to the formation of voids that increase the overall porosity of the matrix. The developed void structure also hindered ultrasonic wave transmission, reducing UPV values. This study demonstrates the potential of hemp waste as a sustainable material for enhancing the thermal performance of building materials. However, fiber surface modification and mixture optimization are necessary to address strength reductions. The findings support the development of sustainable, environmentally friendly building materials.
The sustainable recycling of marine dredged sediment (MDS) presents a significant challenge for global port construction. Aiming to enhance MDS utilization while bypassing high-energy thermal treatment, this study explored the feasibility of using dried MDS in ground granulated blast furnace slag (GBFS)-fly ash (FA) geopolymer. The effects of MDS content on compressive strength development, phase assemblage, and microstructure evolution were systematically evaluated. The results showed that MDS was primarily composed of crystalline phases of quartz, calcite, muscovite and clinochlore, and had a larger particle size and lower pozzolanic reactivity than GBFS and FA. The geopolymer binders with 25% MDS exhibited 28-day compressive strengths of 58.4-71.5 MPa. Although increasing the content to 50% reduced the strengths to 53.7-64.2 MPa, these values still met or exceeded the performance of Grade 52.5 ordinary Portland cement. The strength reduction was primarily attributed to the inherent low reactivity, large particle size, and loose particle structure of MDS, which increased cumulative pore volume, average pore diameter, and induced microcracking development in the binder. A dilution effect was also identified, which increases the Ca/Si and Al/Si ratios of the sodium-containing calcium aluminium-substituted silicate hydrate (C-(N)-A-S-H) gel phase. A higher activator concentration improved the degree of alkali-activation, and consequently enhanced the compressive strengths.
