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Yellow phosphorus slag (YPS) is a byproduct from the production of yellow phosphorus. It has potential pozzolanic activity and can be used as a supplementary cementitious material. However, the early strength of cement mortar decreases significantly with increasing YPS dosage, which restricts the utilization of YPS in cement and concrete. This study aimed to increase the pozzolanic activity of YPS ash by thermal activation. The strength method, alkali dissolution method and polymerization degree method were used to evaluate the effect of thermal activation at different temperatures on the pozzolanic activity of YPS ash. The results showed that YPS ash calcined at 800 °C helps to enhance the early strength because the fluorine in cuspidine (Ca4Si2O7F2) is insoluble, reducing the retarding effect on the mortar. The higher late strength of YPS ash calcined at 100 °C was due to the low polymerization degree of [SiO4]. The pozzolanic activity of YPS ash is positively correlated with the dissolution concentration of (Si + Al) and the compressive strength and negatively associated with the polymerization degree. This paper shows a possibility for the large-scale utilization of YPS. [ABSTRACT FROM AUTHOR]

This research aims to reveal the effect of phosphorus slag (PS) admixtures on the properties and hydration mechanism of circulating fluidized bed fly ash (CFA)-based multi-solid waste cementitious material (CWM). The results indicate that PS as an admixture is more helpful for improving the performance of CWM systems compared with blast furnace slag with a high specific surface area (HBFS) and gasification slag (GS). In this work, CWM2 is prepared with 30 wt.% CFA, 10 wt.% red mud (RM), 20 wt.% blast furnace slag (BFS), 10 wt.% PS, and 30 wt.% cement clinker (CC). The compressive strength and expansion value of CWM2 are the optimal (51.15 MPa and 0.70 mm) when the mass ratio of (Ca + Na)/(Si + Al) is 0.84, which can meet the requirements of 42.5 fly ash Portland cement. In addition, the polymerization degree of CWM2-28 days is the optimum (51.57%) because [PO4] and [SiO4] combine to improve its polymerization structure. The main hydration products are C-S-H gel, C/N-A-S-H gel, and ettringite in CWM, which are conducive to improve the compactness of the micromorphology. In addition, the consolidation of Na, As, Cd, and Hg is promoted in CWM2 by physical encapsulation and charge balance, which meet the drinking water requirements of the World Health Organization (WHO). Therefore, this work provides a new idea for the application of PS as an admixture in CFA-based multi-solid waste cementitious material. [ABSTRACT FROM AUTHOR]

This paper summarized and reviewed the mechanism and macro-performance of alkali-activated metallurgical slag, including steel slag, copper slag, ferronickel slag, and lead-zinc slag. Better activated method and alkali-activator are still needed to be developed to improve the performance of the metallurgical slag with low reactivity. Besides, the chemical components' variation of these metallurgical slags from different regions will lead to unpredictable performance, which needs further study. [ABSTRACT FROM AUTHOR]

The hydration mechanisms of binders containing phosphorous slag at different temperatures were investigated by determining the hydration heat, reaction degree, non-evaporable water content, Ca(OH) 2 content and pore structure of the paste. In addition to plain cement, composite binders containing quartz having a particle size distribution similar to that of phosphorous slag were selected as the control sample. The results show that the retardation effect of the phosphorous slag is greater than its acceleration effect (nucleation effect and dilution effect) on the early hydration of cement. However, increasing the curing temperature tends to reduce the retardation effect of phosphorous slag on the early hydration of cement. The addition of phosphorous slag increases the hydration degree of cement at later ages, particularly at high replacement ratio, but this acceleration effect on the late hydration of cement is weakened at high curing temperature. Under high-temperature curing condition, the reaction degree of phosphorous slag is greater than that under normal-temperature curing condition at all ages, and thus, the contribution of phosphorous slag to the increment of the hydration product and the reduction in Ca(OH) 2 is greater. In the case of standard curing, the pore structure of the paste containing phosphorous slag is coarser than that of the paste containing quartz at early ages, whereas the opposite trend is observed under high-temperature curing condition. At late ages, the pore structure of the paste containing phosphorous slag is finer than those of the plain cement paste and the paste containing quartz for both standard curing and steam curing. Increasing the curing temperature tends to reduce the difference between the compressive strength of the plain cement mortar and that of the mortar containing phosphorous slag at early ages. At the same time, the late-age compressive strength of the mortar containing phosphorous slag surpasses that of the plain cement mortar much more at higher curing temperature. [ABSTRACT FROM AUTHOR]

This paper investigated the hydration properties of steel slag under autoclaved condition (216 °C and 2 MPa). The results show that under autoclaved condition, besides CS and CS, f-CaO and the minerals containing MgO can react sufficiently. The morphologies of Ca(OH) produced by f-CaO are quite different from those produced by CS and CS. The Ca(OH) produced by f-CaO has a larger specific surface area or volume than that produced by CS and CS. The mean Ca-Si ratio of the C-S-H gel produced by steel slag is between 1.7 and 1.9, which is a little smaller than that produced by cement. The reaction of f-CaO tends to cause greater expansion than that of the minerals containing MgO. [ABSTRACT FROM AUTHOR]

Magnesium potassium phosphate cement (MKPC) is an excellent rapid repair material for concrete, and many mineral admixtures have been applied to promote its performance. This study focuses on the quantitative characterization of the physical and chemical contributions of granulated blast-furnace slag with various finenesses to the performance development of MKPC. It was found that the addition of slag could increase the setting time, which is mainly due to the dilution of cement. Fine slag tends to decrease the fluidity of MKPC mortar. The physical contributions of ordinary and ultrafine slag to the early performance of MKPC mortar are 23% and 30%, while the chemical contributions are only 6%~10%. At late ages, the physical contribution is less than 10% and the chemical contribution of slag is even slightly negative. The addition of slag is beneficial to the compact packing of MKPC, which is the main reason for the physical contribution. Slag could react in the MKPC system, and increasing the fineness significantly promotes the reaction kinetics. [ABSTRACT FROM AUTHOR]

Massive high-strength concrete structures tend to have a high risk of cracking. Ground slag powder (GSP), a sustainable and green industrial waste, is suitable for high-strength concrete. We carried out an experimental study of the effects of GSP with a specific surface area of 659 m2/kg on the hydration, pore structure, compressive strength and chloride ion penetrability resistance of high-strength concrete. Results show that adding 25% GSP increases the adiabatic temperature rise of high-strength concrete, whereas adding 45% GSP decreases the initial temperature rise. Incorporating GSP refines the pore structure to the greatest extent and improves the compressive strength and chloride ion penetrability resistance of high-strength concrete, which is more obvious under early temperature-matching curing conditions. Increasing curing temperature has a more obvious impact on the pozzolanic reaction of GSP than cement hydration. From a comprehensive perspective, GSP has potential applications in the cleaner production of green high-strength concrete. [ABSTRACT FROM AUTHOR]

The mechanical properties and hydration mechanism of ultrafine ground granulated blast furnace slag powder (UFS)-cement-steel slag powder (SS) ternary cementitious material systems were studied. The chemical effects and contribution ratios of UFS and SS in ternary system at different hydration ages were also investigated. The results show that by adding UFS, the mechanical properties of concrete composites with high-volume SS conforming to the gap-graded particle size distribution are significantly enhanced. The close-packing effect between particles and the pore size distribution of hardened pastes are improved. The strength of cement matrix without any waste is still the highest. The SS has a negative impact on the hydration and strength development of the system at the early hydration ages, but it has a certain promoting effect at later hydration ages. UFS has a visible improvement effect on the hydration and the strength development of the system at both early and later hydration ages. The contribution ratio of UFS was analyzed and was found to be higher than that of SS apparently. Image 1 • UFS-cement-SS ternary system conforms to the gap-graded particle size distribution. • UFS significantly improves the hydration and strength development of the system. • SS has a promoting effect on late hydration and strength development of the system. • The mechanical properties and microstructure of high-volume SS system are improved. [ABSTRACT FROM AUTHOR]

• The DoH of UFS is 40%–70% larger than that of OS and is 20% at high temperature. • The maximum reaction rate of UFS is 70%–200% larger than that of OS. • The increase of the fineness has little influence on pozzolanic reaction mechanism. • The increase of the surface area attributes to the high reaction rate of UFS. In this study, the kinetics of the pozzolanic reaction of slag with various levels of fineness was characterized by experimental analysis and model simulation. The maximum reaction rate of ultrafine slag at the main pozzolanic reaction peak was found to be 67% larger than that of ordinary slag, with this gap becoming even larger (228%) at a high curing temperature. The early pozzolanic reaction degree was found to increase by 40%–60% due to increased slag fineness. At late ages, the pozzolanic reaction degree was still increased by approximately 40%–70% at room temperature but only by 20% at a high curing temperature due to increased slag fineness. The parameters for the kinetic model illustrate that slag fineness has little influence on the nucleation rate and linear growth rate of the product per unit surface area. However, the increase in the total surface area results in a large number of nuclei for the pozzolanic reaction products, leading to a large amount of product and a high reaction degree for ultrafine slag. The apparent activation energy for the pozzolanic reaction of ultrafine slag was found to be identical to that of ordinary slag, showing that an increase in slag fineness does not change the mechanism governing the pozzolanic reaction. [ABSTRACT FROM AUTHOR]

• Alkali–activated steel slag (AASS) and cement have similar hydration processes and products. • AASS has an earlier and smaller second exothermic peak, and a lower cumulative heat. • AASS has less and poorer crystallization of Ca(OH) 2 , a lower Ca–Si ratio and a similar Al–Si ratio of gels. • AASS has more microcracks, unhydrated particles and Ca(OH) 2 crystals in a single sheet. • The compressive strength of AASS pastes is only 30–40% of the strength of cement pastes. The large quantity of steel slag generated from the iron and steel industry needs to be disposed. Using alkali–activated steel slag as a building material is a good method of comprehensive utilization. In this paper, the properties of steel slag activated by liquid sodium silicate with a silicate modulus of 1.5 as clinker–free cement were investigated. Portland cement with the same water–binder ratio of 0.45 was used as the reference sample. Detailed comparisons including the hydration properties, microstructure characteristics and mechanical strength of the two binders were conducted. The results show that alkali–activated steel slag and cement have similar hydration processes and products. However, the hydration of alkali–activated steel slag has a shorter dormant stage, an earlier and smaller second exothermic peak, a lower cumulative heat, less and poorer crystallization of Ca(OH) 2 , a lower Ca–Si ratio and a similar Al–Si ratio in gels. Compared to the morphology of cement paste, looser microstructure, unhydrated particles and Ca(OH) 2 crystals in a single sheet can be seen in alkali–activated steel slag paste, forming a weak link in the matrix and damaging the strength development. The compressive strengths of alkali–activated steel slag hardened pastes are only 30–40% of the strengths of cement pastes due to poor hydration of former. Therefore, although its efficacy is lower than that of cement, steel slag could replace cement as a building material for certain engineering applications due to its more economic and environmental benefits. [ABSTRACT FROM AUTHOR]

[Display omitted] • The application of YPS in building materials is described. • The activation methods of YPS are introduced. • The effect of YPS on properties of materials is analyzed. • The existing problems and future research needs of YPS are pointed out. Yellow phosphorus slag (YPS) is a solid waste generated in the smelting of phosphorus ore, and its stockpiling pollutes the environment. YPS can be used as a possible raw material of cement, concrete and supplementary cementitious materials (SCM) and so on. YPS as building materials is the best way to achieve large-scale resource recycling of YPS, which can improve the utilization rate of YPS. It can produce economic and environmental benefits, which are conducive to sustainable development. This paper summarizes the research of YPS in building materials and discusses the effect of YPS in terms of mechanical properties, setting time, hydration kinetics, microstructure, workability, and durability. The main disadvantages of YPS in building materials are low early strength and long setting time, which can be improved by mechanical, chemical, thermal and composite activation. Some results of YPS in building materials have been found, but there are challenges in future research. Based on the existing problems of YPS in building materials, some suggestions are provided, and the research direction for further improving the recycling efficiency and cleaner production of YPS is given. [ABSTRACT FROM AUTHOR]

The hydration heat evolution rate and cumulative hydration heat of composite binder containing slag, fly ash or quartz powder and the reaction degrees of slag, fly ash and cement were determined to investigate the hydration heat of slag or fly ash in the composite binder at 25 °C, 45 °C and 60 °C. Results show that a certain amount of hydration heat of slag is observed at 25 °C, but the amount of hydration heat of fly ash is very small at 25 °C. Elevated temperature promotes the hydration of composite binder and increases the reaction degrees of slag and fly ash. Much more amount of hydration heat of slag or fly ash is determined at elevated temperature. The elevated temperature has greater promoting effect on the reaction of slag than fly ash. There is a good linear relationship between the reaction degree of slag (or fly ash) and the hydration heat of slag (or fly ash). The total hydration heats of per gram of slag and per gram of fly ash are 530 J and 285 J, respectively. The result is acceptable due to the slight deviation between the calculated value and experimental value of cumulative hydration heat of composite binder. [ABSTRACT FROM AUTHOR]

[Display omitted] • The utilization rate of CFA in CCM was increased to 40 wt% in this work. • CCM40 was a low-clinker cement because the proportion of clinker was only 30 wt%. • SO 3 and f-CaO in CFA were fully utilized to generate useful hydration products. • Performances of CCM40 were improved by utilization of f-CaO and SO 3. • CCM40 was a green cementitious material whose heavy metals were well consolidated. Circulating fluidized bed fly ash (CFA) is a byproduct that is discharged by circulating fluidized bed (CFB) boilers in coal-fired power plants. CFA is hard to be utilized on a large scale in cementitious materials because it contains many unstable components (SO 3 and f-CaO). This work aims to increase the utilization ratio of CFA in cementitious materials under the utilization of f-CaO and SO 3. In this work, the proportion of CFA in CFA-based low clinker cementitious materials (CCM) is increased to 40 wt% (CCM40), and the mix of cement clinker is only 30 wt%. The main hydration products are C-S-H gel, C-A-S-H gel, and ettringite, which are helpful to the performance development in CCM. Furthermore, the high polymerization of [SiO 4 ] and compact microtopography are reflected in CCM40. The concentrations of heavy metals leaching in CCM40 are the lowest, which meets the drinking water requirements of the World Health Organization (WHO). Therefore, this article offers a novel idea about the large-scale utilization of CFA in cement, and makes the CFA less pollution to the environment. [ABSTRACT FROM AUTHOR]

Coal gasification slag (CGS) is a typical solid waste from the coal gasification process. Reusing CGS into building materials is a key means of realizing its large-scale utilization. This study aims to utilize CGS at a large dosage for the preparation of nonburnt bricks. The CGS, red mud, fly ash and desulfurization ash were utilized to synergistically prepare nonburnt bricks. The mechanical, durability and environmental performance of nonburnt bricks were analysed. Moreover, XRD, thermogravimetric analysis, FTIR, MIP and SEM were conducted to analyse the hydration products and microscopic morphology. The results revealed that when the CGS dosage reached 60%, the best performance of prepared nonburnt bricks was achieved. The unconfined compressive strength was 8.3 MPa at 3 d, 18.2 MPa at 7 d and 24.0 MPa at 28 d. Undergoing 25 cycles of freeze-thaw, the mass loss ratio was 0.9% and strength loss ratio was 10.67%. The alkaline solid wastes (red mud) have a promoting effect on the dissolution of active components in CGS, and the calcium content in blast furnace slag and desulfurization ash, as well as the sulfate in desulfurization ash, can enhance the formation of hydration products. The microstructures displayed the formed clustered C-S-H gels and reticulated C(N)-A-S-H gels tightly wrapped unreacted particles and filled the interstitial spaces of the materials, causing to an elevation in the compactness and a decline in the number of harmful pores. In addition, heavy metals (Cr, As, Cd and Pb) in CGS were well solidified. This study provides a rationale for the harmless and resourceful utilization of CGS. • The mechanical, durability and microscopic properties of CGS-based nonburnt bricks were studied. • The utilization rate of CGS in building materials was increased to 60 wt%. • A compound synergistic existed in nonburnt bricks prepared from CGS, RM, FA and DFA. • CGS-based nonburnt bricks was a green cementitious material whose heavy metals were well consolidated. [ABSTRACT FROM AUTHOR]

• Composite binder with high-volume slag and ITP shows low early compressive strength. • The addition of gypsum compensates for the poor early properties of composite binder. • The addition of gypsum negatively affects later-age properties of composite binder. • Adding gypsum increases Ca/Si ratio and S/Si ratio but doesn't affect Al/Si ratio. • High-volume slag and ITP can be used to produce high performance green concrete. The effect of gypsum on the properties of composite binder containing high-volume slag and iron tailing powder was studied by measuring compressive strength, hydration heat, bound water content, hydration products, pore structure and morphology. The addition of gypsum increases early-age compressive strength and bound water content, but the opposite trend is observed at later ages. A higher quantity of gypsum leads to a higher third exothermic peak and a higher total hydration heat. Although incorporating gypsum promotes early hydration of cement and slag, it limits their further hydration at later ages. Adding gypsum forms a large amount of ettringite and densifies early-age pore structure, but it coarsens later-age pore structure. The addition of gypsum increases Ca/Si and S/Si ratios of C-S-H, but it doesn't affect Al/Si ratio. The addition of gypsum compensates for the poor early-age properties of composite binder containing high-volume slag and iron tailing powder, and the later-age properties are acceptable. [ABSTRACT FROM AUTHOR]

Blast furnace slag (BFS) is commonly used as a substitute for cement clinker due to its hydration properties. However, the demand for BFS is outpacing the supply, and its price is rising steadily. Moreover, the significant accumulation of industrial waste with potential hydration properties poses a severe environmental threat. To address these challenges, this paper aimed to prepare high-performance composite blast furnace slag powder (CBFS) by incorporating red mud (RM), fly ash (FA), desulfurization gypsum (DG) and BFS, guided by the synergistic effects and the theory of medium-calcium systems. This paper reveals that the primary activation methods of the amorphous silicon-aluminum mineral phases in CBFS are alkali activation and sulfate activation. The optimal results demonstrate that the compressive strength of CBFS-cementitious material (50% CBFS + 50% cement) can reach 52.8 MPa, meeting the standards of Portland Cement PO 42.5. Additionally, RM, FA and DG account for 66% of CBFS and the hydration activity of CBFS is better than that of S95-grade BFS. Furthermore, the CBFS-cementitious material effectively immobilizes hazardous elements of the raw materials, and the leachate meets drinking water standards. The application of CBFS facilitates the recycling of industrial solid wastes, improves the quality of construction materials and reduces the construction industry's dependence on BFS. [Display omitted] • CBFS was prepared using RM, FA, DG, and BFS, aiming to achieve integrated clean production in multiple industries. • The total content of RM, FA and DG in CBFS reaches 66%, and its properties meet the requirements of S95-grade BFS. • RM, FA, DG and BFS showed a positive synergistic effect in CBFS, which enhanced the strength of the matrix (52.8 MPa). • CBFS can reduce carbon emissions in the cement industry and solidify the hazardous elements in the raw materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The physical and chemical properties of two types of CGS were compared. • The research status of CGS in construction materials and high value-added materials is summarized. • The future research needs of CGS in construction materials and high value-added materials are pointed out. Coal gasification slag (CGS) is a byproduct of the coal gasification process. According to the different particle sizes, CGS is generally divided into coarse slag and fine slag. The industrial recycling and reuse of CGS has the shortcomings of a low efficiency, high cost and poor scale effect. Generally, it is disposed via pile storage and landfills, which causes Significant environmental contamination and waste of land resources, adversely affecting the sustainable development of coal chemical industry enterprises. The resource utilization of CGS depends mainly on its two properties, the large amount of active amorphous silica-alumina and the loose porous structural properties. There are four general categories of uses for gasification, for construction materials, silica-based materials, activated carbon materials, and valued element extraction. In particular, the use for the preparation of construction materials is considered an effective strategy for the treatment and utilization of CGS in large quantities. While the synthesis of silica-based porous materials and activated carbon materials can improve the application value of CGS. This paper summarizes the physicochemical properties and morphological structure of CGS, and reviews its research progress in construction building materials and high value-added materials. It is also hoped that high value-added materials can be combined with building material preparation to prepare special building materials. Finally, the problems in the utilization of CGS resources and the prospects for efficient utilization in the future are discussed to facilitate subsequent researchers to better understand the properties and utilization directions of CGS. [ABSTRACT FROM AUTHOR]

Ferronickel slag (FNS) is a solid waste produced in the smelting of ferronickel alloys. FNS is classified as blast furnace ferronickel slag (BFS) and electric furnace ferronickel slag (EFS). They are useful in many fields, such as metal recovery and glass manufacturing. In fact, replacing cement or concrete aggregate is the best way to achieve large-scale resource recycling of FNS, while generating environmental and economic benefits, which is consistent with the concept of sustainable development. This paper summarizes the research papers of FNS as supplementary cementitious materials (SCMs), aggregates and precursors and comprehensively analyses of the sustainable utilization of FNS. The results suggest that BFS is suitable for use as SCMs with small replacement and relatively high activity, but it needs to be ground to 400–500 m2/kg. EFS is suitable for use as aggregate due to its high discharge and strong interlocking ability of particles. The influence of FNS on the performance of geopolymer concrete is mainly related to the types of precursor and activator. Combined with the results of this paper, the research direction of further improving the recycling efficiency and cleaner production of FNS is given. [ABSTRACT FROM AUTHOR]

[Display omitted] • Converter steelmaking slag (CSS) is utilized based on synergy of multi-solid waste. • Harmful elements in raw are consolidated by CSS-based cementitious material (RB). • Low-activity calcium silicate in CSS is activated to improve performances of RB. • RB is low-carbon cementitious materials because dosage of cement is reduced to 30%. This research aims to activate the low-activity calcium silicate in converter steelmaking slag (CSS) under the synergy of multiple solid wastes, and further increase the dosage of CSS in cementitious materials. In this work, the CSS-based cementitious material (RB) is composed by converter steelmaking slag (CSS), Bayer red mud (BRM), blast furnace slag (BFS), and pulverized coal furnace fly ash (PFA). More importantly, the low-activity calcium silicate in CSS is activated to generate extra C S H gel based on the synergy of CSS, BRM, BFS, and PFA in RB4 (RB4 is an RB with a mass ratio of (Ca + Na)/(Si + Al) is 1.33). Thus, the compressive strength of RB4 in 28 days grows to 53.40 MPa. In parallel, the dosage of CSS in RB is increased to 30 wt%. The main hydration products are C S H gel, ettringite, N A S H gel, and C A S H gel, which facilitate the performance growth of RBs. The dense microstructure and better pore structure of RB are presented when the mass ratio of (Ca + Na)/(Si + Al) is 1.33. Additionally, the consolidation of harmful elements in RB4 is improved by synergy of CSS, BRM, BFS, and PFA, and their leaching results meet the relevant standards of drinking water. This work is expected to provide an effective method for the synergistic utilization of CSS, BRM, BFS, and PFA in green cementitious materials. [ABSTRACT FROM AUTHOR]

The effects of ultrafine slag on the hydration heat, fluidity, rheological properties and setting time of Portland cement paste were investigated. The exothermic rate and total hydration heat of composite binder containing ultrafine slag are much higher than that of composite paste containing ordinary slag. The addition of ultrafine slag significantly reduces the fluidity of composite paste. The fluidity loss rate of paste containing ultrafine slag is evidently high compared to the paste containing the same amount of ordinary slag. The addition of ultrafine slag have an adverse effect on the rheological behavior of paste. The yield stress and plastic viscosity of paste containing ultrafine slag increase significantly with increasing the ultrafine slag content and rest time. The addition of ultrafine slag reduces the setting time of composite paste, while adding ordinary slag prolongs the setting time. Reducing water/binder ratio significantly shortens the setting time of paste containing ultrafine slag. [Display omitted] • Adding UFS obviously promotes the early hydration of composite binder. • The hydration heat of composite paste containing UFS increases significantly. • Composite binder with UFS has poor fluidity and large fluidity loss rate. • The addition of UFS negatively affects rheological property of composite paste. • The addition of UFS can reduce the setting time of the composite paste. [ABSTRACT FROM AUTHOR]

• Ferronickel slag reduces the exothermic rate and cumulative hydration heat at 25°C. • The high temperature greatly promotes the hydration of binder with ferronickel slag. • The hydration kinetics process at 60°C is different from that at 25°C and 45°C. • Ferronickel slag has a smaller effect on the overall hydration than slag. • Ferronickel slag has a greater effect on the overall hydration than fly ash. The hydration heat of composite binder containing up to 70 % blast furnace ferronickel slag (BFFS) was determined at 25°C, 45°C and 60°C. The hydration kinetics process and parameters were simulated and analysed. BFFS shows pozzolanic activity in a strong alkaline solution. Increasing the BFFS content retards hydration and reduces the exothermic rate. The high temperature dramatically promotes hydration, especially for the composite binder containing no more than 30 % BFFS. The hydration kinetics process involves nucleation and crystal growth (NG) → interactions at phase boundaries (I) → diffusion (D) at 25°C and 45°C. However, this process becomes NG → D at 60°C. The addition of BFFS decreases the overall hydration rate. BFFS has a smaller effect on the overall hydration of the composite binder than ground granulated blast furnace slag, but has a greater effect than fly ash. [ABSTRACT FROM AUTHOR]

• High-volume iron tailing powder (HVITP) concrete has lower total temperature rise. • Properties of HVITP concrete are poor compared with high-volume fly ash concrete. • Later-age properties of HVITP concrete are adversely affected by high temperature. • Reducing water/binder ratio or adding slag improves the properties of HVITP concrete. • The use of HVITP concrete in massive concrete engineering should pay more attention. The mechanical properties, microstructure and permeability of high-volume iron tailing powder (HVITP) concrete and high-volume fly ash (HVFA) concrete were comparatively investigated by measuring the adiabatic temperature rise, rate of temperature rise, compressive strength, splitting tensile strength and chloride permeability grade of concrete and determining the pore structure, bound water content and morphology of paste. The total adiabatic temperature rise of HVITP concrete are lower than that of HVFA concrete. But the early higher rate of temperature rise of HVITP concrete is obtained. The HVITP concrete shows low compressive strength and splitting tensile strength, coarse pore structure, loose microstructure and high chloride permeability compared with HVFA concrete with the same water/binder ratio. The early temperature matching curing (TMC) adversely affects the later-age properties development of HVITP concrete, but it promotes the properties development of HVFA concrete. The decrease in water/binder ratio or the partial replacement of ITP with slag improves the properties of HVITP concrete, especially for the early properties under TMC condition. But these two means still lead to properties difference between HVITP concrete and HVFA concrete due to the low reactivity of ITP. [ABSTRACT FROM AUTHOR]