Elevated Temperature Curing Research Articles

Sulphate influence on strength development of cemented paste backfill with superplasticizer under field-like curing conditions

This study investigates the impact of sulphate on the strength development of cemented paste backfill (CPB) with polycarboxylate ether-based superplasticizers (PES) under curing conditions mimicking real field environments. These conditions include thermal (T, non-isothermal field temperature), hydraulic (H, drainage), mechanical (M, overburden stress), and chemical (C, PES, sulphate ions) factors. CPB samples with varying sulphate and PES contents were examined through mechanical and microstructural tests under these THMC conditions. The findings reveal that traditional methods for assessing sulphate influence on CPB strength, typically under standard lab conditions, do not adequately capture the mechanical response of CPB structures to sulphate in field scenarios. Real field curing conditions such as temperature, drainage, and stress significantly affect CPB’s mechanical response to sulphate. CPB samples incorporating PES and sulphate show notable improvements in early-age strength, emphasizing the beneficial role of elevated temperatures and the complex relationship between drainage, sulphate, and strength development. Elevated curing temperatures counterbalance sulphate's negative effects, boosting initial strength, while drainage conditions play a critical role in strength development by facilitating the removal of sulphate ions and reducing capillary water. Additionally, stress application at the start of curing aids solid particle rearrangement, promoting the release of free water and enhancing mechanical strength. The competitive adsorption between sulphate ions and PES on the cementitious matrix influences the dispersion of particles and strength development. This research offers crucial technical insights for designing durable CPB mixes suited to various on-site curing conditions, particularly enhancing initial strength across diverse field curing scenarios.

Multiphysical testing of strength development of cemented paste backfill containing superplasticizer

Current laboratory procedures for curing and testing the mechanical strength of cemented paste backfill (CPB) do not take into account the complex Multiphysics (thermal, T; hydraulic, H; mechanical, M; chemical, C) processes that CPB structures are subjected to in the field. This oversight can lead to unreliable measurements and unsafe designs. In this study, a multiphysical curing and testing procedures for CPB with superplasticizer (CPB-PES) has been developed to evaluate its strength development under THMC curing conditions close to those encountered in the field. The obtained results demonstrated that the strength development of CPB-PES is greatly affected by the THMC factors and their interactions. The contributions of each one of the investigated THMC factors on the strength are not equally similar and greatly depend on the interaction between these factors and curing time. CPB samples with 0.125 % PES that underwent drainage during THMC curing showed a strength increase of up to 809 % after 28 days of curing, compared to the control samples. The strength of CPB-PES samples cured under THMC can be up to 57 % higher than that of samples cured under THC conditions. The results indicate a significant interaction between thermal (T; elevated field curing temperature) and chemical (C; superplasticizer and cement hydration) factors, between chemical (C) and mechanical (M; field curing stress) factors, as well as between thermal and mechanical factors. The influence of the mechanical factor on strength development was observed to be less pronounced compared to the impact of chemical and thermal factor, and is reduced at elevated curing temperatures. The findings underscore the critical importance of accounting for field-relevant THMC factors and their interactions in the determination of the CPB-PES strength development, which is essential for the design of safer and more economical CPB structures, ultimately enhancing mine productivity and safety.

On the surface roughness properties of fly ash-based geopolymer mortars with teff straw ash from the image analysis viewpoint

Fly ash (FA)-based geopolymer mortar is being considered for sustainability since it enjoys peculiar properties such as high mechanical properties and environmental benefits. However, the high curing temperatures of FA-based geopolymer mortar play a complex role in its outstanding mechanical behaviour thereby requiring other precursors, such as teff straw ash (TSA). In this study, we develop surface roughness properties of FA-based geopolymer mortars with TSA, where the ambient temperature is used for curing. The surface roughness characteristics of the FA-based geopolymer mortars with TSA exploit the surface roughness simulations from Gwyddion and the approach is demonstrated here in the contexts of spatial, hybrid and amplitude roughness parameters. The results show that some roughness parameters, including Ra and Rq values for FA-based geopolymer mortars with TSA, exhibit significant decreasing trends as the TSA contents increase. However, in comparison with the CA specimens (ambient temperature curing) and CE specimens (elevated temperature curing), the trends among the majority of the roughness parameters for FA-based geopolymer mortars with TSA turn out not to be very good probably due to changes in the internal structures of the mortars. Moreover, without the kurtosis values (Rku) of less than 3, it is easy to demonstrate that all the profiles of the investigated specimens reflect sharp valleys and peaks. The findings of surface roughness properties allow one to grasp the roughness parameters of FA-based geopolymer mortars with TSA. The approach for generating surface roughness properties of FA-based geopolymer mortars with TSA offers significant quantitative and qualitative information required for the bonding of mortar layers.

Propiedades de un hormigón de alto desempeño fabricado con un proceso de producción convencional

Among cement-based composites, materials that show a growing interest are the High Performance Concrete (HPC) and Ultra-hi-gh Performance Concrete (UHPC), which are categorized by an effective screening of granular elements, and an elevated quantity of fiber reinforcement [1]. HPC is produced through the particle packing methodology to enhance its matrix density and reduce its porosity [2]. Because of this producing me-thod, this material has a lower water content than conventional concrete, and better me-chanical performance and durability [3]-[5]. It is thus suitable to build several structural elements [6], [7] thanks to its enhanced pro-perties. On the other hand, the manufacture of HPC is not straightforward: expensive raw materials, impact on the environment, labo-rious fabrication and curing tasks [8], [9] are among the most important obstacles to its large-scale use. It is therefore relevant and recommended to simplify its production process. This work present new HPC mixtu-res that are produced in a straightforward manner, without requiring elevated tempe-rature curing conditions, mixers with high power or temperature controlled chambers, as commonly used for current HPC sold in the market. The mixtures described here showed a split tensile strength of 5 MPa, a compressive strength of over 70 MPa, and a virtual packing density of 0.86.

Additively Manufactured Silicone Polymer Composite with High Hydrogen Getter Content and Hydrogen Absorption Capacity.

Hydrogen getters consisting of 1,4-bis[phenylethynyl] benzene (DEB) and a carbon-supported palladium catalyst (Pd/C) have been used to mitigate the accumulation of unwanted hydrogen gas in a sealed system. Here, we report the formulation of a composite resin consisting of silicone polymer plus DEB-Pd/C as an active getter material and the additive manufacturing of silicone getter composites with a high getter content (up to 50 wt %). NMR and DSC studies suggest no reaction between the silicone polymer resin and DEB even at elevated curing temperatures (75 °C). Getter composites with varying amounts of getter and filler were formulated, and their rheological properties were studied. The two composite resins with good printability parameters and different getter contents were chosen to make 3D-printed samples. The hydrogen absorption capacity of these samples was studied at a low hydrogen pressure of 750 mTorr of pure hydrogen. The getter composite with 50 wt% of getter showed normalized DEB conversion of 83%, with the hydrogen adsorption capacity of 100.2 mL of H2 per gram of polymer getter composite.

Effects of calcined phosphogypsum replacement on hydration and properties of calcium sulfoaluminate cement at different curing temperatures

The present research aims to understand the cement hydration and microstructure formation mechanism of calcined phosphogypsum (CPG) supplemented calcium sulfoaluminate (CSA) pastes cured under hot-weather temperatures and to ensure the appropriate application and effective service of CSA cement-based materials, as well as to address the problem of overstocking of CPG. The effects of CPG dosage on the heat of hydration, electrical resistivity, hydration products, and bound water content of CSA cement pastes were investigated at curing temperatures of 20 °C, 35 °C, and 50 °C. Hydration kinetics was studied to elucidate the hydration mechanism, and thermodynamic modelling was performed to predict the phase assemblages. The results show that the incorporation of CPG facilitated the formation of ettringite and significantly reduced the transformation of ettringite to monosulfate, and these phenomena were enhanced with an increase in the CPG. The addition of CPG at elevated curing temperature (35 °C and 50 °C) significantly improved the compressive strength of CSA cement pastes. The growth rate and nucleation rate predicted by the BNG model for the CSA cement pastes cured at 50 °C were substantially higher compared to those at 20 °C.

Lime-activated one-part geopolymer mortars from construction, demolition and industrial wastes

This work focused on the production of one-part geopolymer mortars from construction and demolition wastes (CDW) blended with steel slag. Previous related studies on geopolymer production from CDW utilized conventional two-part geopolymers comprised of highly alkaline activator solutions and CDW materials. Thus, the study's significance consists in producing high-strength (≥35 MPa) ambient-cured mortars from CDW with predominantly concrete waste by replacing conventional highly alkaline activator solutions with an environmentally-friendly alkaline activator, Ca(OH)2 powder. Four mortar mixtures were produced with CDW contents ranging from 50 to 65 % dry weight, varying the brick waste content from 3 to 18 %. The effect of elevated temperature (40 °C) curing was also considered. The results showed that 55 % CDW content had optimum performance across all parameters studied such as compressive and flexural strengths, setting time, as well as changes in nuclear magnetic resonance (NMR)-determined pore structure (porosity and mean pore size) and x-ray diffraction (XRD)-determined degree of crystallinity over time. It had 28-day compressive and flexural strengths of 42 and 5.8 MPa, respectively, and initial and final setting times of 25 and 50 min. The importance of sufficient brick waste content in the geopolymer mixtures for effective mechanical performance is highlighted. The inclusion of concrete waste in powder form reduced compressive strength under ambient curing but improved performance at 40 °C curing. It is concluded that sustainable structural mortars can be produced by ‘just adding water’ to an optimized CDW mixture with predominantly concrete waste blended with brick waste and slag and activated by powdered Ca(OH)2.

Effect of curing temperature on hydration and microstructure evolution of cement-based composites with extremely low w/b ratio

The challenge of high geo-temperature often occurred during the construction of deep buried tunnels, and to uncover the effect of varied curing temperature on hydration and microstructure evolution of cement-based composites with extremely low w/b ratio, samples were prepared with a w/b ratio of 0.18 and mixed with different fibers, silica fume and fly ash. Hydration kinetics, main hydration product phases and the evolution of C–S–H inside the samples were analyzed. It was found that the time for maximum heat release peak under 40 °C and 60 °C was earlier than that under 20 °C. The hydration heat of steel fiber composites was lower than that of PP fiber composites. 40 °C curing temperature can motivated the chemical activity of samples and promoted the hydration process, multi-stage peaks appeared at 60 °C curing condition. Q0-Q4 of C–S–H were observed in samples, and the mean silicate chain length (MCL) of C–S–H from 29Si NMR analysis was increased mostly by 15.6% with the elevated curing temperature. This study will provide much support to the safe construction of deep buried tunnels.

Comprehensive study on the hydration kinetics, mechanical properties and autogenous shrinkage of cement pastes during steam curing

Steam curing is a crucial stage for the strength development of steam-cured concrete. This study comprehensively investigated the hydration kinetics, mechanical properties, and autogenous shrinkage (AS) of cement pastes during steam curing. A hydration-dependent analytical method was proposed to analyze the mechanisms governing the development of mechanical properties and AS of steam-cured cement pastes (SCPs). Results revealed that in this investigated curing regimes, the peak hydration rate of SCPs was approximately 7 times higher than that of standard-cured pastes (NCPs). SCPs exhibited faster time-dependent mechanical property development but slower hydration-dependent mechanical property development than NCPs. This difference was primarily attributed to variations in initial structure establishment and free water content. Moreover, an elevated curing temperature reduced the growth rate of hydration-dependent AS due to large capillary pores and low surface tension, which suggested that AS should not be considered as a cause of heat damage to SCPs.

Effect of Curing Temperature on Mechanical Properties of Sanitary Ware Porcelain based Geopolymer Mortar

The objective of this study was to investigate the effect of curing temperature on the mechanical properties of sanitary ware porcelain powder-based geopolymer paste and mortar under various curing temperatures. The setting time, porosity, water absorption, and compressive strength of specimens mixed with alkaline concentrations of 8M, 10M, 12M, and 14M were compared. All mortar cube (50×50×50 mm) specimens were placed into drying ovens for 24 hours at 60°C, 75°C, 90°C, and 105°C, respectively. The specimens were then air-cured for 1, 3, 7, 14, and 28 days. The results showed that the elevated curing temperature accelerated the polymerization process of the porcelain geopolymerization reaction. The setting time varied between 89 mins and 380 mins. It showed variability depending on alkaline concentration and initial curing temperature. The setting time of pastes decreased when alkaline concentrations increased. An increasing temperature in the drying oven decreased the initial and final setting times. Similar to this, the rate of water absorption and permeability of porcelain-based geopolymer mortar specimens decreased with drying oven temperatures and increments in alkaline concentration. The lowest water absorption and porosity of the specimen were 2.1% and 15.7%, respectively. The compressive strength increased as drying oven temperatures and alkaline concentrations increased. The highest 28 day compressive strength was found in 14M specimens with 105°C curing temperatures. The ultimate compressive strength was 64.45 N/mm2. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were investigated to study the microstructural properties of the geopolymers. Doi: 10.28991/CEJ-2023-09-08-01 Full Text: PDF

Effect of Si/Al molar ratio and curing temperatures on the immobilization of radioactive borate waste in metakaolin-based geopolymer waste form

Immobilization of radioactive borate waste (RBW) using a geopolymer with a high Si/Al ratio has been challenging because boron-silicon networks lower the compressive strength and delay the setting time. In this study, metakaolin-based geopolymer waste form to immobilize simulant RBW was fabricated using different Si/Al ratios (1.0–1.4) and curing temperatures (26 and 60 ℃). The 7-day compressive strength results revealed that a certain amount of silicon and an elevated curing temperature are required to achieve high compressive strength and waste loading. Following waste acceptance criteria tests, all geopolymers exhibited compressive strengths higher than 3.445 MPa. The leachability index of boron was higher than 6.0, and the leaching mechanism was identified as diffusion. No significant structural changes in the geopolymer were observed after thermal cycling and gamma irradiation tests. The physically bound or unincorporated RBW was leached out of the geopolymer during water immersion and leaching tests; however, boron, which was chemically connected with silicon, was present as an inert phase together with a geopolymer binder. Consequently, immobilizing RBW using a geopolymer with a low Si/Al ratio (1.4) is beneficial in terms of RBW loading and structural durability.

The Effect of Curing Temperature and Thickness of Polybutyl Methacrylate Siloxane Coatings on the Corrosion Protection of Structural Steel S355

This study aimed to determine the effects of coating thickness and curing temperature on the properties of a polybutyl methacrylate-siloxane coating deposited on structural steel S355. First, the thermal properties of the sol as a function of temperature were investigated using thermogravimetric analysis coupled with mass spectrometry and differential scanning calorimetry. After coating deposition on structural steel S355 using a dip-coating process, the coating composition and porosity were evaluated using Fourier transform infrared spectroscopy and photothermal beam deflection spectroscopy. In the second part, coating thickness, topography, and corrosion properties were studied as functions of withdrawal rate during deposition. The corrosion properties of variously prepared coatings were evaluated using electrochemical impedance measurements in 3.5 wt.% NaCl and salt spray testing according to the ASTM B117 standard. An elevated curing temperature (at 150 °C) of the polybutyl methacrylate siloxane sol-gel coating impairs greater crosslinking and lower porosity, while the optimal thickness of 4 μm is achieved with the appropriate withdrawal rate to obtain a homogeneous, defect-free surface. Under these optimal conditions, the protection of structural steel against corrosion in a chloride environment lasting for more than 6 months can be achieved.

Spring-in of composite L-shape specimens: An experimental and numerical investigation

The effect of stacking sequence, specimen thickness, tooling material and curing cycle on process induced distortions of L-shape composite structures is investigated experimentally and numerically. Sixty specimens were manufactured, and their spring-in angle was compared against simulation and analytical results. A thermo-chemo-mechanical simulation approach was developed to simulate the experiment by employing a modified Cure Hardening Instantaneously Linear Elastic (CHILE) and a linear viscoelastic material model. Freestanding, fixed and contact boundary conditions were investigated. The spring-in angle of the parts predicted by the modified CHILE material model, was found to be higher than that predicted by the viscoelastic model. The tool material significantly affects the distortion of the parts and contact boundary conditions should be employed for an accurate prediction of the part shape. Balanced, symmetric and thick laminates contribute to a reduction in part distortion, while elevated curing temperatures slightly affect the distortion level of the parts.

Mineral-impregnated carbon-fiber (MCF) composites made with differently sized fly-ash geopolymers for durable light weight and high temperature applications

For a wide application of carbon-fiber reinforcement in large-scaled, lightweight construction, mineral-impregnated carbon-fiber (MCF) composites provide a promising alternative to rebar or reinforcement made of non-metallic fibers and polymer matrix. The penetration ability of the aluminosilicate particles is a key factor for a stable, reproducible impregnation and the maximal reinforcing efficiency of continuous fiber geopolymer composites.The work at hand focuses on the influence of the particle sizes of geopolymer precursors on the processing quality, microstructural development and final composite performance regarding the flexural, tensile and pullout behavior. Three differently sized fly ash (FA) sources were used to impregnate a carbon fiber heavy tow before curing at 75 °C. FA particles in the same size range as the filament diameter proved to be the most efficient, enhancing both mechanical properties of MCF and its bond to concrete matrix, well beyond the effects induced by other, coarser precursors. The results of the microscopic investigation, μCT, thermal gravimetric analyzes and mercury intrusion porosimetry measurements show that the use of this particle fraction resulted in the best fiber-matrix distribution over the cross-section, densest microstructure and highest fiber volume fraction in the impregnated yarn. Furthermore, the geopolymerization kinetics of all FAs at ambient temperature and at 75 °C were determined by isothermal calorimeter, showing an increase in the reaction rate with elevated curing temperature and higher particle finesse.

Effect of curing conditions on the strength and durability of air entrained concrete with and without fly ash

In cold regions, air entrained concrete has been widely used against freeze–thaw deterioration. This paper studied the influence of curing conditions on the strength and durability of air entrained ordinary portland cement (OPC) and fly ash (FA) concrete. Four different curing conditions including standard curing (SC), air curing (AC), mild temperature curing (MC), and elevated temperature curing (EC) were utilized to cure the cast specimens. The compressive strength at 3, 7, 14, and 28 days was measured respectively. Also, the water absorption, sorptivity, air void system, as well as freeze–thaw durability after 28 days of curing were investigated. Test results suggested that AC condition impeded the strength gain of both concrete, but it affected FA concrete more than OPC concrete. EC condition improved the early-age strength while compromised the later-age strength of OPC concrete, whereas EC condition improved the compressive strength of FA concrete at both early ages and later ages. AC condition has more adverse effects on water absorption as well as sorptivity of FA concrete than those of OPC concrete. EC condition increased the water absorption and sorptivity of OPC concrete, whereas reduced the water absorption and sorptivity of FA concrete. Although the air content in fresh OPC and FA concrete were comparable, FA concrete had less proportion of microvoids (air voids smaller than 300 μm), larger spacing factor but smaller specific surface, regardless of curing conditions. EC condition caused the reduction in air content, the increase of spacing factor, and decrease of specific surface. For both OPC concrete and FA concrete, the four curing conditions produced different freeze–thaw durability factor (DF), but all the specimens passed the failure limit of 60 %. The freeze–thaw test results based on specimens under SC condition may overestimate the DF.

Effects of Wood Flour and Curing Temperature on Some Properties of the Polyurethane Foam Core in a Wood-Based Sandwich Panel

The objectives of this study were to examine the chemical, physical, and mechanical properties of polyurethane (PU) foam prepared with various wood flour contents and curing temperatures for use as a core layer in wood-based sandwich panels. The five alternative wood flour contents tested were 2, 4, 6, 8, 10, and 12%, and the alternative curing temperatures 100, 120, 140, and 160°C were studied with 10% wood flour content. The results showed that the cell size and density of the PU foam increased at wood contents above 6%, which reduced the compressive strength of the samples. It was also found for PU with 10% wood content that curing at 100 to 160°C caused a decrease in foam density by 50%, compared with PU foam cured under the standard conditions (i.e., at room temperature). SEM and cell size measurements show the anisotropy of PU foam and the increase of foam cell diameter when increasing the curing temperature from standard condition to 140°C. Consequently, the compressive strength and its specific value declined abruptly at elevated curing temperatures, starting from 100°C. These results suggest that elevated curing temperatures cause degradation of the properties of wood-filled PU foam, due to effects on foam cell structure.

Effect of curing temperature on the reaction kinetics of cementitious steel slag-fly ash-desulfurized gypsum composites system

Solid waste-based binders have been widely studied for decades. Recently, the steel slag-fly ash-desulfurized gypsum (SS-FA-DG) composite system was developed as a novel building cementitious material, however, its reaction mechanism and reaction process mains unclear. This paper investigated the reaction kinetics of SS-FA-DG composite system by evaluating the influence of curing temperature on the formation of hydration products and the development of mechanical properties. The pH of the SS-FA-DG slurry was measured by the online pH meter. The compressive strength, chemical bonding, mineral composition, and degree of hydration of cementitious SS-FA-DG blocks over a curing period of 28 days were evaluated using compression tests, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analyses, respectively. The results indicate that the SS-FA-DG composite system was found to develop via a five-stage process: dissolution of steel slag (I) and fly ash (Ⅱ), formation of hydration products such as calcium silicate hydrate gels (C–S–H) and ettringite (AFt) crystallite (Ⅲ), nucleation and crystallization of hydration products (Ⅳ), and growth and diffusion (Ⅴ). The compressive strength was largely governed by the development of the hydration reaction, which is influenced by the curing temperature. The reaction time of each stage was shortened at elevated curing temperatures, thereby increasing the compressive strength of the material more quickly. • The cementitious SS-FA-DG block was prepared by compression molding technology. • The compressive strength of the cementitious SS-FA-DG block can reach 35.6MPa after curing for 5 days at 60 °C, and it can reach 59.6MPa after curing for 42 days. • The reaction mechanism and reaction process of SS-FA-DG are investigated. • The hydration reaction of SS-FA-DG composite system can be divided into five stages.

Enabling sustainable rapid construction with high volume GGBS concrete through elevated temperature curing and maturity testing

Nowadays, low carbon footprint concrete for construction relies heavily on ground granulated blast-furnace slag (GGBS) as a partial cement replacement material (CRM) in places where other CRMs are in short supply. However, it is relatively well-known that the low early-age strengths of GGBS concretes discourage the maximisation of cement replacement in most applications; a constraint which can be potentially overcome through exploitation of hydration acceleration under elevated temperature curing. Concrete and mortar mixes of 47 MPa 28-day target mean cube strength were developed and investigated in this study with various percentages of GGBS (0, 20, 35, 50 and 70%) and cured under isothermal and non-isothermal regimes (20, 30, 40 and 50 °C and adiabatic). Higher temperatures appeared to significantly accelerate the strength gain of GGBS concretes, particularly those containing high GGBS percentages. In-situ strength development may be estimated through maturity functions which were initially developed for neat Portland cement concretes. The accuracy of several maturity functions, such as the Nurse-Saul, Arrhenius, Weighted Maturity, Weaver-Sadgrove and Rastrup ones, were examined together with two strength-maturity/time correlations. It was found that although maturity methods can be used to optimise a concrete mix in terms of GGBS content and depending on the application, it is not possible to obtain consistently reliable estimates for GGBS concretes from the current functions. Nonetheless, from the current models considered, the Arrhenius, Weighted Maturity and Rastrup functions appear as more appropriate for higher replacement levels of cement with GGBS. Overall, the present study highlighted a need for further improving maturity functions to account for the strength development of GGBS concrete.

Synthesis of Geopolymer Concrete Using Flyash

Geopolymer concrete (GPC) reduces the environmental impacts of conventional Portland cement concrete, therefore, this research aims to investigate the compressive characteristics of GPC by utilizing the readily available industrial waste i.e., coal based Flyash in the Khyber Pakhtunkhwa province of Pakistan. For the preparation of GPC, Na2SiO3 was used as an activator. After the preparation of GPC specimens, their compressive characteristics were investigated at different ages of specimens, Flyash content, curing time, and curing conditions. Moreover, the relationship between compressive strength and modulus of elasticity of GPC was also evaluated. From the testing of GPC specimens in a compression testing machine (CTM), their compressive strength was found to be similar to that of conventional Portland cement concrete i.e., in the range of 20-40 MPa tested at the age of 7 and 28 days respectively. Furthermore, elevated temperature curing was found to increase the compressive strength of GPC significantly as compared to that of ambient curing. From the cost analysis, Flyash-based GPC was found to be cost effective as compared to conventional Portland cement concrete

Phosphorus slag in supplementary cementitious and alkali activated materials: A review on activation methods

• Accelerated hydration of PS via activation methods is reviewed. • Review on using PS as blended cement in SCM and as a precursor in AAM. • Combined activation method has the best performance despite high PS as cement replacement. Supplementary cementitious materials (SCM) and alkali activated materials (AAM) are widely researched as alternative binder in concrete due to potential for reducing greenhouse gas emissions by utilizing industrial by-products. Phosphorus slag (PS) is the by-product of yellow phosphorus industry, which can partially substitute ordinary Portland cement (OPC) and reduce carbon footprint. This paper provides a comprehensive review of different activation methods (mechanical, thermal, chemical and alkali activation) to study the factors affecting the mechanical properties and underlying mechanism of PS as binder in SCM and precursor in AAM. The major drawback of PS in cement-based materials or concrete is the low early strength and long setting time due to the presence of P 2 O 5 , and this intensifies as the PS replacement amount increases. The mechanical activation by increasing the fineness, utilization of chemical activators and elevated curing temperature to improve the early-age performance of PS blended cement (PSC) are summarized. Specifically, the effect of these activation methods with different PS replacement level on cement paste, mortar or concrete are discussed in terms of compressive strength, setting time and microstructure. Combined activation gives the best outcome in improving early age properties of PSC. The composition of PS, replacement level and fineness of PS, curing temperature and method, type and dosage of activator are highlighted in this paper. Generally, the optimal PS replacement level is 30 – 40% in non-activated PSC, while activated PSC with proper activators can increase the PS replacement level to 35% – 80% or even fully replace OPC in AAM system.