To address the inefficient utilization of electrolytic manganese residue(EMR)caused by its high inert content,this study developed a multifunctional solid waste cementitious material by replacing 50-60%of ordinary Por...To address the inefficient utilization of electrolytic manganese residue(EMR)caused by its high inert content,this study developed a multifunctional solid waste cementitious material by replacing 50-60%of ordinary Portland cement(PO 42.5)with wet-ground electrolytic manganese residue(WEMR),wetground granulated blast-furnace slag(WGBFS),and carbide slag(CS).The mechanical properties,hydration characteristics,microstructure,and carbon emissions of the material were systematically investigated with varying WEMR dosages.The experimental results demonstrates that the wet-grinding process significantly refines the particle size and enhances the reactivity of both EMR and GBFS.As the WEMR dosage increases,the 28-day compressive strength initially rise and then declines.Optimal mechanical performance was achieved with 24%WEMR and 6%CS,yielding a 28-day compressive strength of 48.2 MPa.Advanced analytical techniques,including XRD,TG-DTG,SEM,and MIP,were employed to examine the hydration products.The findings reveal that the wet-grinding-alkali-sulfur synergistic activation system in the multi-solid waste cementitious material effectively utilize EMR to generate abundant hydration products such as AFt and C-(A)-S-H.Additionally,the fine particles of WEMR fill the pores in the mortar,further enhancing compressive strength.The cost and carbon emissions of this multifunctional system are only 65.97%and 46.9% of those of PO 42.5,respectively.This study provides a feasible approach for the efficient utilization of EMR,contributing to sustainable construction practices.展开更多
To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated ...To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated salt composite phase change material(HSCPCM)with dual phase transition temperature zones has been proposed.This HSCPCM,denoted as SDMA10,combines hydrophilic modified expanded graphite,an acrylic emulsion coating,and eutectic hydrated salts to achieve leakage prevention,enhanced thermal stability,cycling stability,and superior phase change behavior.Battery modules incorporating SDMA10 demonstrate significant thermal control capabilities.Specifically,the cylindrical battery modules with SDMA10 can maintain maximum operating temperatures below 55°C at 4 C discharge rate,while prismatic battery modules can keep maximum operating temperatures below 65°C at 2 C discharge rate.In extreme battery overheating conditions simulated using heating plates,SDMA10 effectively suppresses thermal propagation.Even when the central heating plate reaches 300°C,the maximum temperature at the module edge heating plates remains below 85°C.Further,compared to organic composite phase change materials(CPCMs),the battery module with SDMA10 can further reduce the peak thermal runaway temperature by 93°C and delay the thermal runaway trigger time by 689 s,thereby significantly decreasing heat diffusion.Therefore,the designed HSCPCM integrates excellent latent heat storage and thermochemical storage capabilities,providing high thermal energy storage density within the thermal management and thermal runaway threshold temperature range.This research will offer a promising pathway for improving the thermal safety performance of battery packs in electric vehicles and other energy storage systems.展开更多
In order to adjust some properties of cement grout or concrete,some mineral admixtures are usually added in the preparation.Admixtures can reduce the cement consumption and save the cost,and also adjust the workabilit...In order to adjust some properties of cement grout or concrete,some mineral admixtures are usually added in the preparation.Admixtures can reduce the cement consumption and save the cost,and also adjust the workability of the material,improve the strength and durability of the cement stone,or reduce hydration heat of the composite cement.At present,the content of fly ash or slag is generally less than 50%among the composite cementitious materials that have been studied more,but there is little research on composite cementitious materials with large mineral admixture.In this paper,XRD,SEM,and adiabatic temperature rise tests were used to discuss hydration products and mechanism of composite cement grout with 90%content of fly ash and slag.The results show that the hydration of the composite cement grout is an alkali-activated hydration reaction,and the hydration products are mainly amorphous substances such as hydrated calcium silicate or hydrated calcium aluminate gel.The hydration reaction temperature rise is much lower than that of ordinary cement grout,and the time of the temperature peak is significantly delayed.展开更多
As the second most important solid waste produced by coal-fired power plants,the improper management of coal-fired slag has the potential to result in environmental pollution.It is therefore imperative that high-value...As the second most important solid waste produced by coal-fired power plants,the improper management of coal-fired slag has the potential to result in environmental pollution.It is therefore imperative that high-value utilization pathways for coal-fired slag should be developed.In this study,modified magnesium slag(MMS),produced by a magnesium smelter,was selected as the alkali activator.The activated silica-aluminum solid wastes,namely coal-fired slag(CFS)and mineral powder(MP),were employed as pozzolanic materials in the preparation of alkali-activated cementitious materials.The alkali-activated cementitious materials prepared with 50 wt%MMS,40 wt%CFS and 10 wt%MP exhibited favorable mechanical properties,with a compressive strength of 32.804 MPa in the paste sample cured for 28 d.Then,the activated silica-aluminum solid waste consisting of CFS-MP generated a significant amount of C-S(A)-H gels,AFt,and other products,which were observed to occupy the pore structure of the specimen.In addition,the secondary hydration reaction of CFS-MP occurs in high alkalinity environments,resulting in the formation of a mutually stimulated and promoted reaction system between CFS-MP and MMS,this will subsequently accelerate the hydrolysis reaction of MMS.It is important to emphasize that the amount of MMS in alkali-activated cementitious materials must be strictly regulated to avert the potential issue of incomplete depolymerization-repolymerization of active silica-aluminum solid waste containing CFS-MP.This in turn could have a deleterious impact on the late strength of the cementitious materials.The aim of this work is to improve the joint disposal of MMS,CFS and MP and thereby provide a scientific basis for the development of environmentally friendly and low-carbon modified magnesium slag alkali-activated coal-fired slag based cementitious materials for mine backfilling.展开更多
The rheological and mechanical properties of high-strength anchorage grouting materials for highway slope were investigated to optimize the mix proportion. The experimental results showed that the optimized mix propor...The rheological and mechanical properties of high-strength anchorage grouting materials for highway slope were investigated to optimize the mix proportion. The experimental results showed that the optimized mix proportion of high-strength anchorage grouting material （HAGM） was C3 （FA：SP-SF= 1：2：2; AGI：AG2=3：7 and 0.03% FC）, which is agreement with the limitation of JCT 986-2005. Moreover, the XRD and FTIR results showed the addition of expansive components was in favor of the formation of ettringite. The intensity of AFt oeak of the samnles increased with the increasing of hydration time.展开更多
To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of ...To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of the Krstulovi？-Dabi？ model. An isothermal calorimeter was used to characterize the hydration heat evolution. The results show that the hydration of RGC is controlled by the processes of nucleation and crystal growth（NG）, interaction at phase boundaries（I）, and diffusion（D） in order, and the pozzolanic reactions of slag and compound-activated red mud-coal gangue are mainly controlled by the I process. Slag accelerates the clinker hydration during NG process, whereas the compound-activated red mud-coal gangue retards the hydration of RGC and the time required for I process increases with increasing dosage of red mud-coal gangue in RGC.展开更多
The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration product...The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak.展开更多
By means of low-field nuclear magnetic resonance(LF-NMR),the transverse relaxation time(T_(2))signals of physically bound water in cement paste were monitored to indicate water content change and characterize the earl...By means of low-field nuclear magnetic resonance(LF-NMR),the transverse relaxation time(T_(2))signals of physically bound water in cement paste were monitored to indicate water content change and characterize the early-age hydration process.With the curves of the T_(2)signals and hydration time obtained,the hydration process could be divided into four typical periods using the null points of the second derivative curve,and the influences of water-cement ratio(w/c)and hydration heat regulating materials(HHRM)on hydration process were analyzed.The experimental results showed that the hydration rate of pure cement paste in accelerated period presented a positive correlation with w/c.Compared to pure cement paste,the addition of HHRM extended all four periods,and led to a much faster hydration rate in initial period as well as a slower rate in accelerated period.Finally,according to the LFNMR test results,the early-age hydration model of cementitious materials was proposed considering w/c and HHRM content.展开更多
The morphologies and hydration properties of MgO expansive material at different curing temperatures were investigated.When the curing temperature varies from 25℃to 50℃,the conductivity of MgO rises from 40 to 80μs...The morphologies and hydration properties of MgO expansive material at different curing temperatures were investigated.When the curing temperature varies from 25℃to 50℃,the conductivity of MgO rises from 40 to 80μs/cm,the hydration product of MgO expansive material curing in water for 28 days is from 1.5—2 mm to 2—2.5μm in length through SEM observation,and the expansion of pastes with 5%of the magnesium oxide is from 0.36%up to 1.01%,it is increased by 2.78 times.When the content of cement paste increases to 95%and cured in water for 90 days,the brucite forms as hexaflaggy?shaped crystal,which is less than 0.1μm and tends to aggregates.The effect of curing temperature on the hydration of MgO expansive material is obvious.展开更多
To obtain the compositions and microstructure of hydration products of cementitious material in different hydration ages and its growth law of filling strength, the optimal proportion of composite cementitious materia...To obtain the compositions and microstructure of hydration products of cementitious material in different hydration ages and its growth law of filling strength, the optimal proportion of composite cementitious material was determined according to the chemical composition of cement clinker which was composed of the Portland cement 32.5R, CSA 42.5 sulphoaluminate cement and two gypsum（CS）. The characterization of composite cementitious materials in different hydration ages was conducted by NMR, XRD and SEM techniques. The mechanism of hydration was explored. It is shown that the compressive strength of the test block increases gradually with the increase of hydration age. The microstructure of composite cementitious material can be changed from Al-O octahedron into Al-O tetrahedron in the hydration process. The hydrated alkali alumi niumsilicate formed with Si-O tetrahedron and Al-O tetrahedron. The degree of polymerization of Si-O tetrahedron gradually increased, and the structural strength of cementitious materials continued to increase. The diffraction peak of clinker minerals gradually decreased with the extension of hydration age. The CaSO4 completely hydrated to produce Aft during hydration which resulted in high early strength of cementitious material. The early hydration product of composite cementitious materials was Aft with a needle bar structure. The main middle and last hydration products were CSH gel and CH gel with dense prismatic shape. The microscopic pore of composite cementitious material gradually decreased and improved the later strength of filling block. The strong support was provided for mined-out area.展开更多
This paper studied the effects of different retarders on the performance of the"one-step"alkali-activated composite cementitious material(ACCM)which is composed of ground granulated blast slag(GGBS)and fly a...This paper studied the effects of different retarders on the performance of the"one-step"alkali-activated composite cementitious material(ACCM)which is composed of ground granulated blast slag(GGBS)and fly ash(FA),and analyzed its mechanical properties,hydration mechanism,and retardation mechanism.The effects of retarders on the hydration products,mechanical properties,and hydration kinetics of ACCM were investigated using XRD,SEM,FTIR,EDS,and thermoactive microcalorimetry.The results showed that Na_(2)B_(4)O_(7)·10H_(2)O(B)delayed the exotherm during the alkali activation process and could effectively delay the setting time of ACCM,but the mechanical properties were slightly decreased.The setting time of ACCM increased with the increase in SG content,but the mechanical properties of ACCM decreased with the increase in SG content.C1_(2)H_(22)O_(11)(CHO)could effectively delay the hydration reaction of ACCM and weakly enhanced the compressive strength.H_(3)PO_(4)(HP)at a concentration of 0.05 mol/L had a certain effect on ACCM retardation,but HP at a concentration of 0.07 and 0.09 mol/L had an effect of promoting the setting and hardening time of ACCM.展开更多
The dielectric permittivity of cementitious materials during 24 hours hydration period at a frequency of 2.45 GHz using a network analyzer with open-ended probe technique was measured. Influences of water-to-cementiti...The dielectric permittivity of cementitious materials during 24 hours hydration period at a frequency of 2.45 GHz using a network analyzer with open-ended probe technique was measured. Influences of water-to-cementitious ratios, cement types, pozzolans and aggregate types are taken into consideration. The results show that dielectric permittivity is strongly affected by initial water-to-cementitious ratio and the rate of hydration reaction which can be changed by fineness of cement (Types 1 and 3), pozzolan materials and aggregates (river sand with/without crushed limestone rock). Dielectric permittivity is relatively high and remains constant during the dormant period, after that it decreases rapidly when the hydration reaction resumes and continues to decrease during the acceleratory period.展开更多
In order to realize the full resource utilization of ferronickel slag(FNS)in cement-based materials,this paper studied the influences of mechanical grinding activation on the physical and chemical properties and react...In order to realize the full resource utilization of ferronickel slag(FNS)in cement-based materials,this paper studied the influences of mechanical grinding activation on the physical and chemical properties and reactivity of ferrous extraction tailing of nickel slag(FETNS).Four grinding processes of 5,10,20 and 30 min were set up to evaluate the influence of grinding process on the physical and chemical properties of FETNS with the aid of BET,XRD,Rietveld analysis and particle size distribution.The cement-FETNS composite cementitious material was prepared by replacing cement with 0%,10%,15%,20%,25%and 30%FETNS.The influence of FETNS fineness and content on the properties of composite cementitious system were characterized by mechanical properties,reaction products,early hydration process and pore structure characteristics.The results show that the grinding process can effectively improve the pozzolanic activity of FETNS.The compressive strength of FETNS-M_(30)paste is higher than that of FETNS-M_(5) paste in the early and late stages,and the later strength is higher than that of the baseline group when the content of FETNS-M_(30)is 10%-25%.The pozzolanic activity of FETNS-M_(30)powder is significantly improved and higher than that of FETNS-M_(5) powder.Under the same content,the Ca/Si ratio of C-S-H gel in FETNS-M_(30)paste is small,and the degree of silicate polymerization is higher.When the FETNS-M_(30)content is 10%,the proportions of favorable pores d<50 nm(harmless pores and less-harmful pores)of FETNS-M_(5) paste and FETNS-M_(30)paste is 95.3%and 95.4%,respectively,indicating a denser pore structure of the FETNS-M_(30)paste.展开更多
AC impedance is a new method to study the changes of pore structure and the hydration degree during the hydration and hardening process of cement paste by the change of the electrochemical parameters. Employing AC imp...AC impedance is a new method to study the changes of pore structure and the hydration degree during the hydration and hardening process of cement paste by the change of the electrochemical parameters. Employing AC impedance method, we studied the hydration and hardening process of cement paste with fly ash and slag, and analyzed the influence of different hydration age, water-binder ratio and mineral admixture on the impedance parameters. Moreover, we compared the results with those by the conventional porosity testing method and X-ray diffraction method. The results showed that AC impedance could be taken as a new technology in cement and concrete research.展开更多
As a byproduct of water treatment,drinking water treatment aluminum sludge(DWTAS)has challenges related to imperfect treatment and disposal,which has caused potential harm to human health and the environment.In this p...As a byproduct of water treatment,drinking water treatment aluminum sludge(DWTAS)has challenges related to imperfect treatment and disposal,which has caused potential harm to human health and the environment.In this paper,heat treatment DWTAS as a supplement cementitious material was used to prepare a green cementing material.The results show that the 800℃ is considered as the optimum heat treatment temperature for DWTAS.DWTAS-800℃ is fully activated after thermal decomposition to form incompletely crystallized highly activeγ-Al_(2)O_(3) and active SiO_(2).The addition of DWTAS promoted the formation of ettringite and C-(A)-S-H gel,which could make up for the low early compressive strength of cementing materials to a certain extent.When cured for 90 days,the compressive strength of the mortar with 30% DWTAS-800℃ reached 44.86 MPa.The dynamic process was well simulated by Krstulovi′c-Dabi′c hydration kinetics model.This study provided a methodology for the fabrication of environmentally friendly and cost-effective compound cementitiousmaterials and proposed a“waste-to-resource”strategy for the sustainable management of typical solid wastes.展开更多
In this study, we have focused our investigations on effect of adding hydrated lime on a locally made composite material, based on clayey earth (soil) and Hibiscus sabdariffa fibres, for envelope (walls) in the buildi...In this study, we have focused our investigations on effect of adding hydrated lime on a locally made composite material, based on clayey earth (soil) and Hibiscus sabdariffa fibres, for envelope (walls) in the building. Prior to sample’s formulation, we selected an appropriate mineral (soil) material based on criteria as: plasticizer power for good workability, dense coarse particles to withstand loads and finally porous structure to take advantage of air insulating character. We then formulated, following a mixing process by shearing and compaction by vibration that we recommend, two composite materials (A), (B) which contain respectively 1% Fibres plus 1% lime, 1% Fibres plus 3% lime. We determined thermal properties by the mean of KD2 Pro thermal analyzer, compression strength accordingly to the standard NF P 18-406, porosity following volumetric and gravimetric methods and pH of soil-hydrated lime solution. As results, up to 5% of hydrated lime, the measured pH is inferior to 12: mineralization of vegetal fibres is highly unlikely. Moreover, we observe that the addition of hydrated lime resulted in a reduction in the number of cracks and their depths;Samples (A) and (B) have a rather compact appearance than the case 1% Fibres without lime (material (C)). Furthermore, with lime stabilization, the insulating potential is improved while the thermal inertia has been deteriorated compared to material (C). However, compressive strength decreases with lime, which could be due to the presence of fibres that would inhibit the hardening of the lime. At last, with 3.39% ± 3.07% MPa, 2.27% ± 11.30% MPa for samples (A), (B) respectively, the minimum required by CRATerre-EAG (guide of CDI, 1996) for construction of envelope (walls) of single storey (ground floor) buildings is met.展开更多
The interaction of Si anions with Al sites during the hydration process was observed by NMR, IR and SEM to understand the reaction mechanism of the hydrates formation mixed with oil shale calcined at different tempera...The interaction of Si anions with Al sites during the hydration process was observed by NMR, IR and SEM to understand the reaction mechanism of the hydrates formation mixed with oil shale calcined at different temperatures. As the reaction progressed, the coordination of Al （Ⅳ, Ⅴ, and Ⅵ） changed almost completely to Ⅳ, when mixed with oil shale calcined at 700 ℃. However, when mixed with oil shale calcined at 400 ℃, some 6-coordination of Al still remained in the hydrates. Under the function of alkaline solutions, which were produced with the hydration of clinker, a certain amount of Si and Al atoms dissolved or hydrolyzed from aluminosilicate, formed geomonomers in solutions, and then polycondensed to form networks.展开更多
Magnesia-calcium materials have stable hot performance,good resistance to the erosion and corrosion of liquid steel and steel slag,and a special role in purifying liquid steel,so they are widely used in iron and steel...Magnesia-calcium materials have stable hot performance,good resistance to the erosion and corrosion of liquid steel and steel slag,and a special role in purifying liquid steel,so they are widely used in iron and steel industry.However,hydration of magnesia-calcium materials seriously restricts their use,so researches have been done to improve their hydration resistance,obtaining a series of achievements.In this paper,the improvements on the hydration resistance of magnesia-calcium materials by additives in recent 20 years were presented,and their mechanisms were summarized.展开更多
The rational design of high-performance electrochemical energy storage devices critically depends on a fundamental understanding of ion-electrode interactions at the molecular scale.Herein,we employ interpretable mach...The rational design of high-performance electrochemical energy storage devices critically depends on a fundamental understanding of ion-electrode interactions at the molecular scale.Herein,we employ interpretable machine learning(ML)to reveal electrolyte hydration energy as a universal descriptor governing ion-specific capacitance in two-dimensional(2D)materials.Through explainable ML,we elucidate how ion hydration shell stability and size critically influence charge transport and storage at the electrode-electrolyte interface.Our analysis identifies hydration energy-not ionic size-as the primary factor dictating capacitance,challenging prevailing assumptions and providing quantifiable design rules for electrolyte selection.These insights offer a data-driven pathway to optimize 2D materials for supercapacitors and beyond,including batteries and electrocatalytic systems.This work demonstrates the power of explainable artificial intelligence in uncovering molecular-level mechanisms that accelerate the discovery and development of next-generation energy storage technologies.展开更多
Main performance of the cement grouting materials made up by Portland cement（PC） and sulphoaluminate cement（SAC） was investigated in this program, a kind of expanding agent（EA） which was mainly constituted by me...Main performance of the cement grouting materials made up by Portland cement（PC） and sulphoaluminate cement（SAC） was investigated in this program, a kind of expanding agent（EA） which was mainly constituted by metakaolin and alunite was utilized for the compensation of the shrinkage, the hydration products and micro structure of the grouting materials were researched by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that a high expansion rate of the grouting materials could be reached as the expanding agent mixed in 6% of PC mass; the addition of SAC in the S2（PC：SAC：EA=34：6：2.25） brought a further improvement of the expansion rate of the grouting materials, the analysis of XRD and SEM showed that due to the reaction of expanding agent and SAC in the grouting materials, more ettringite crystal was generated, which resulted in a higher early strength, the addition of SAC played an expansion and strength reinforcement role in the grouting materials.展开更多
基金Funded by the Guangxi Key Research and Development Program(Nos.GK AB24010020,and GK AB23026071)the Key Project of Guangxi Natural Science Foundation(No.2025GXNSFDA090046)the Guangxi Science and Technology Base and Talent Special Project(No.GK AD24010062)。
文摘To address the inefficient utilization of electrolytic manganese residue(EMR)caused by its high inert content,this study developed a multifunctional solid waste cementitious material by replacing 50-60%of ordinary Portland cement(PO 42.5)with wet-ground electrolytic manganese residue(WEMR),wetground granulated blast-furnace slag(WGBFS),and carbide slag(CS).The mechanical properties,hydration characteristics,microstructure,and carbon emissions of the material were systematically investigated with varying WEMR dosages.The experimental results demonstrates that the wet-grinding process significantly refines the particle size and enhances the reactivity of both EMR and GBFS.As the WEMR dosage increases,the 28-day compressive strength initially rise and then declines.Optimal mechanical performance was achieved with 24%WEMR and 6%CS,yielding a 28-day compressive strength of 48.2 MPa.Advanced analytical techniques,including XRD,TG-DTG,SEM,and MIP,were employed to examine the hydration products.The findings reveal that the wet-grinding-alkali-sulfur synergistic activation system in the multi-solid waste cementitious material effectively utilize EMR to generate abundant hydration products such as AFt and C-(A)-S-H.Additionally,the fine particles of WEMR fill the pores in the mortar,further enhancing compressive strength.The cost and carbon emissions of this multifunctional system are only 65.97%and 46.9% of those of PO 42.5,respectively.This study provides a feasible approach for the efficient utilization of EMR,contributing to sustainable construction practices.
基金financially supported by Natural Science Foundation of Guangdong province(2024A1515010228)CATARC Automotive Inspection Center Excellent Engineer Program(2023B0909050007).
文摘To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated salt composite phase change material(HSCPCM)with dual phase transition temperature zones has been proposed.This HSCPCM,denoted as SDMA10,combines hydrophilic modified expanded graphite,an acrylic emulsion coating,and eutectic hydrated salts to achieve leakage prevention,enhanced thermal stability,cycling stability,and superior phase change behavior.Battery modules incorporating SDMA10 demonstrate significant thermal control capabilities.Specifically,the cylindrical battery modules with SDMA10 can maintain maximum operating temperatures below 55°C at 4 C discharge rate,while prismatic battery modules can keep maximum operating temperatures below 65°C at 2 C discharge rate.In extreme battery overheating conditions simulated using heating plates,SDMA10 effectively suppresses thermal propagation.Even when the central heating plate reaches 300°C,the maximum temperature at the module edge heating plates remains below 85°C.Further,compared to organic composite phase change materials(CPCMs),the battery module with SDMA10 can further reduce the peak thermal runaway temperature by 93°C and delay the thermal runaway trigger time by 689 s,thereby significantly decreasing heat diffusion.Therefore,the designed HSCPCM integrates excellent latent heat storage and thermochemical storage capabilities,providing high thermal energy storage density within the thermal management and thermal runaway threshold temperature range.This research will offer a promising pathway for improving the thermal safety performance of battery packs in electric vehicles and other energy storage systems.
文摘In order to adjust some properties of cement grout or concrete,some mineral admixtures are usually added in the preparation.Admixtures can reduce the cement consumption and save the cost,and also adjust the workability of the material,improve the strength and durability of the cement stone,or reduce hydration heat of the composite cement.At present,the content of fly ash or slag is generally less than 50%among the composite cementitious materials that have been studied more,but there is little research on composite cementitious materials with large mineral admixture.In this paper,XRD,SEM,and adiabatic temperature rise tests were used to discuss hydration products and mechanism of composite cement grout with 90%content of fly ash and slag.The results show that the hydration of the composite cement grout is an alkali-activated hydration reaction,and the hydration products are mainly amorphous substances such as hydrated calcium silicate or hydrated calcium aluminate gel.The hydration reaction temperature rise is much lower than that of ordinary cement grout,and the time of the temperature peak is significantly delayed.
基金Projects(52222404,52074212)supported by the National Natural Science Foundation of ChinaProject(2023-LL-QY-07)supported by the Two-chain Integration Key Projects in Shaanxi Province,China。
文摘As the second most important solid waste produced by coal-fired power plants,the improper management of coal-fired slag has the potential to result in environmental pollution.It is therefore imperative that high-value utilization pathways for coal-fired slag should be developed.In this study,modified magnesium slag(MMS),produced by a magnesium smelter,was selected as the alkali activator.The activated silica-aluminum solid wastes,namely coal-fired slag(CFS)and mineral powder(MP),were employed as pozzolanic materials in the preparation of alkali-activated cementitious materials.The alkali-activated cementitious materials prepared with 50 wt%MMS,40 wt%CFS and 10 wt%MP exhibited favorable mechanical properties,with a compressive strength of 32.804 MPa in the paste sample cured for 28 d.Then,the activated silica-aluminum solid waste consisting of CFS-MP generated a significant amount of C-S(A)-H gels,AFt,and other products,which were observed to occupy the pore structure of the specimen.In addition,the secondary hydration reaction of CFS-MP occurs in high alkalinity environments,resulting in the formation of a mutually stimulated and promoted reaction system between CFS-MP and MMS,this will subsequently accelerate the hydrolysis reaction of MMS.It is important to emphasize that the amount of MMS in alkali-activated cementitious materials must be strictly regulated to avert the potential issue of incomplete depolymerization-repolymerization of active silica-aluminum solid waste containing CFS-MP.This in turn could have a deleterious impact on the late strength of the cementitious materials.The aim of this work is to improve the joint disposal of MMS,CFS and MP and thereby provide a scientific basis for the development of environmentally friendly and low-carbon modified magnesium slag alkali-activated coal-fired slag based cementitious materials for mine backfilling.
基金Funded by the National Natural Science Foundation of China(No.41202226)the Program for Department of Communications of Yunnan Province(No.2009(A)1-09)
文摘The rheological and mechanical properties of high-strength anchorage grouting materials for highway slope were investigated to optimize the mix proportion. The experimental results showed that the optimized mix proportion of high-strength anchorage grouting material （HAGM） was C3 （FA：SP-SF= 1：2：2; AGI：AG2=3：7 and 0.03% FC）, which is agreement with the limitation of JCT 986-2005. Moreover, the XRD and FTIR results showed the addition of expansive components was in favor of the formation of ettringite. The intensity of AFt oeak of the samnles increased with the increasing of hydration time.
基金financially supported by the National Natural Science Foundation of China(Nos.51302012 and 51234008)the China Postdoctoral Science Foundation(No.2016M590046)
文摘To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of the Krstulovi？-Dabi？ model. An isothermal calorimeter was used to characterize the hydration heat evolution. The results show that the hydration of RGC is controlled by the processes of nucleation and crystal growth（NG）, interaction at phase boundaries（I）, and diffusion（D） in order, and the pozzolanic reactions of slag and compound-activated red mud-coal gangue are mainly controlled by the I process. Slag accelerates the clinker hydration during NG process, whereas the compound-activated red mud-coal gangue retards the hydration of RGC and the time required for I process increases with increasing dosage of red mud-coal gangue in RGC.
基金Project(51208391) supported by the National Natural Science Foundation of China
文摘The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak.
基金Funded by National Natural Science Foundation of China(Nos.U1965105,51878245)National Key R&D Program of China(No.2021YFF0500802)。
文摘By means of low-field nuclear magnetic resonance(LF-NMR),the transverse relaxation time(T_(2))signals of physically bound water in cement paste were monitored to indicate water content change and characterize the early-age hydration process.With the curves of the T_(2)signals and hydration time obtained,the hydration process could be divided into four typical periods using the null points of the second derivative curve,and the influences of water-cement ratio(w/c)and hydration heat regulating materials(HHRM)on hydration process were analyzed.The experimental results showed that the hydration rate of pure cement paste in accelerated period presented a positive correlation with w/c.Compared to pure cement paste,the addition of HHRM extended all four periods,and led to a much faster hydration rate in initial period as well as a slower rate in accelerated period.Finally,according to the LFNMR test results,the early-age hydration model of cementitious materials was proposed considering w/c and HHRM content.
基金the Research Center on Levee Safety Disaster Prevention, MWR (No. 2019004)High-level Talent Project Funding Scheme of Jiangsu (No. XCL-CXTD-007)+3 种基金China Postdoctoral Science Foundation (No. 2018M630559)the National Natural Science Foundation of China (No. 51908285)the Fundamental Research Nantong Metro Group Co., Ltdthe traffic construction science and technology project of Shanxi (No. 16-2-08) for its financial support in this project
文摘The morphologies and hydration properties of MgO expansive material at different curing temperatures were investigated.When the curing temperature varies from 25℃to 50℃,the conductivity of MgO rises from 40 to 80μs/cm,the hydration product of MgO expansive material curing in water for 28 days is from 1.5—2 mm to 2—2.5μm in length through SEM observation,and the expansion of pastes with 5%of the magnesium oxide is from 0.36%up to 1.01%,it is increased by 2.78 times.When the content of cement paste increases to 95%and cured in water for 90 days,the brucite forms as hexaflaggy?shaped crystal,which is less than 0.1μm and tends to aggregates.The effect of curing temperature on the hydration of MgO expansive material is obvious.
基金Funded by the National Natural Science Foundation of China(No.51574055)the Natural Science Foundation of Liaoning Province(No.20170540143)
文摘To obtain the compositions and microstructure of hydration products of cementitious material in different hydration ages and its growth law of filling strength, the optimal proportion of composite cementitious material was determined according to the chemical composition of cement clinker which was composed of the Portland cement 32.5R, CSA 42.5 sulphoaluminate cement and two gypsum（CS）. The characterization of composite cementitious materials in different hydration ages was conducted by NMR, XRD and SEM techniques. The mechanism of hydration was explored. It is shown that the compressive strength of the test block increases gradually with the increase of hydration age. The microstructure of composite cementitious material can be changed from Al-O octahedron into Al-O tetrahedron in the hydration process. The hydrated alkali alumi niumsilicate formed with Si-O tetrahedron and Al-O tetrahedron. The degree of polymerization of Si-O tetrahedron gradually increased, and the structural strength of cementitious materials continued to increase. The diffraction peak of clinker minerals gradually decreased with the extension of hydration age. The CaSO4 completely hydrated to produce Aft during hydration which resulted in high early strength of cementitious material. The early hydration product of composite cementitious materials was Aft with a needle bar structure. The main middle and last hydration products were CSH gel and CH gel with dense prismatic shape. The microscopic pore of composite cementitious material gradually decreased and improved the later strength of filling block. The strong support was provided for mined-out area.
基金Funded by Key Laboratory for Comprehensive Energy Saving of Cold Regions Architecture of Ministry of Education(No.JLJZHDKF202204)。
文摘This paper studied the effects of different retarders on the performance of the"one-step"alkali-activated composite cementitious material(ACCM)which is composed of ground granulated blast slag(GGBS)and fly ash(FA),and analyzed its mechanical properties,hydration mechanism,and retardation mechanism.The effects of retarders on the hydration products,mechanical properties,and hydration kinetics of ACCM were investigated using XRD,SEM,FTIR,EDS,and thermoactive microcalorimetry.The results showed that Na_(2)B_(4)O_(7)·10H_(2)O(B)delayed the exotherm during the alkali activation process and could effectively delay the setting time of ACCM,but the mechanical properties were slightly decreased.The setting time of ACCM increased with the increase in SG content,but the mechanical properties of ACCM decreased with the increase in SG content.C1_(2)H_(22)O_(11)(CHO)could effectively delay the hydration reaction of ACCM and weakly enhanced the compressive strength.H_(3)PO_(4)(HP)at a concentration of 0.05 mol/L had a certain effect on ACCM retardation,but HP at a concentration of 0.07 and 0.09 mol/L had an effect of promoting the setting and hardening time of ACCM.
文摘The dielectric permittivity of cementitious materials during 24 hours hydration period at a frequency of 2.45 GHz using a network analyzer with open-ended probe technique was measured. Influences of water-to-cementitious ratios, cement types, pozzolans and aggregate types are taken into consideration. The results show that dielectric permittivity is strongly affected by initial water-to-cementitious ratio and the rate of hydration reaction which can be changed by fineness of cement (Types 1 and 3), pozzolan materials and aggregates (river sand with/without crushed limestone rock). Dielectric permittivity is relatively high and remains constant during the dormant period, after that it decreases rapidly when the hydration reaction resumes and continues to decrease during the acceleratory period.
基金Funded by the Science and Technology Program of Gansu Province(Nos.25CXGA070,24JRRA213)the National Natural Science Foundation of China(Nos.52468036,52178216,U21A20150)。
文摘In order to realize the full resource utilization of ferronickel slag(FNS)in cement-based materials,this paper studied the influences of mechanical grinding activation on the physical and chemical properties and reactivity of ferrous extraction tailing of nickel slag(FETNS).Four grinding processes of 5,10,20 and 30 min were set up to evaluate the influence of grinding process on the physical and chemical properties of FETNS with the aid of BET,XRD,Rietveld analysis and particle size distribution.The cement-FETNS composite cementitious material was prepared by replacing cement with 0%,10%,15%,20%,25%and 30%FETNS.The influence of FETNS fineness and content on the properties of composite cementitious system were characterized by mechanical properties,reaction products,early hydration process and pore structure characteristics.The results show that the grinding process can effectively improve the pozzolanic activity of FETNS.The compressive strength of FETNS-M_(30)paste is higher than that of FETNS-M_(5) paste in the early and late stages,and the later strength is higher than that of the baseline group when the content of FETNS-M_(30)is 10%-25%.The pozzolanic activity of FETNS-M_(30)powder is significantly improved and higher than that of FETNS-M_(5) powder.Under the same content,the Ca/Si ratio of C-S-H gel in FETNS-M_(30)paste is small,and the degree of silicate polymerization is higher.When the FETNS-M_(30)content is 10%,the proportions of favorable pores d<50 nm(harmless pores and less-harmful pores)of FETNS-M_(5) paste and FETNS-M_(30)paste is 95.3%and 95.4%,respectively,indicating a denser pore structure of the FETNS-M_(30)paste.
基金Funded the Major Sate Basic Research Development Program of China(973 Program)(No.2009CB23201)Beijing Natural Science Foundation(No.8100001)National Natural Science Foundation of China(No.51278014)
文摘AC impedance is a new method to study the changes of pore structure and the hydration degree during the hydration and hardening process of cement paste by the change of the electrochemical parameters. Employing AC impedance method, we studied the hydration and hardening process of cement paste with fly ash and slag, and analyzed the influence of different hydration age, water-binder ratio and mineral admixture on the impedance parameters. Moreover, we compared the results with those by the conventional porosity testing method and X-ray diffraction method. The results showed that AC impedance could be taken as a new technology in cement and concrete research.
基金This work is supported by the National Key Research and Development Program of China(No.2022YFC3203203)the Outstanding Youth Science Foundation of Shaanxi Province(No.2023-JC-JQ-36)the National Natural Science Foundation of China(No.52300121).
文摘As a byproduct of water treatment,drinking water treatment aluminum sludge(DWTAS)has challenges related to imperfect treatment and disposal,which has caused potential harm to human health and the environment.In this paper,heat treatment DWTAS as a supplement cementitious material was used to prepare a green cementing material.The results show that the 800℃ is considered as the optimum heat treatment temperature for DWTAS.DWTAS-800℃ is fully activated after thermal decomposition to form incompletely crystallized highly activeγ-Al_(2)O_(3) and active SiO_(2).The addition of DWTAS promoted the formation of ettringite and C-(A)-S-H gel,which could make up for the low early compressive strength of cementing materials to a certain extent.When cured for 90 days,the compressive strength of the mortar with 30% DWTAS-800℃ reached 44.86 MPa.The dynamic process was well simulated by Krstulovi′c-Dabi′c hydration kinetics model.This study provided a methodology for the fabrication of environmentally friendly and cost-effective compound cementitiousmaterials and proposed a“waste-to-resource”strategy for the sustainable management of typical solid wastes.
文摘In this study, we have focused our investigations on effect of adding hydrated lime on a locally made composite material, based on clayey earth (soil) and Hibiscus sabdariffa fibres, for envelope (walls) in the building. Prior to sample’s formulation, we selected an appropriate mineral (soil) material based on criteria as: plasticizer power for good workability, dense coarse particles to withstand loads and finally porous structure to take advantage of air insulating character. We then formulated, following a mixing process by shearing and compaction by vibration that we recommend, two composite materials (A), (B) which contain respectively 1% Fibres plus 1% lime, 1% Fibres plus 3% lime. We determined thermal properties by the mean of KD2 Pro thermal analyzer, compression strength accordingly to the standard NF P 18-406, porosity following volumetric and gravimetric methods and pH of soil-hydrated lime solution. As results, up to 5% of hydrated lime, the measured pH is inferior to 12: mineralization of vegetal fibres is highly unlikely. Moreover, we observe that the addition of hydrated lime resulted in a reduction in the number of cracks and their depths;Samples (A) and (B) have a rather compact appearance than the case 1% Fibres without lime (material (C)). Furthermore, with lime stabilization, the insulating potential is improved while the thermal inertia has been deteriorated compared to material (C). However, compressive strength decreases with lime, which could be due to the presence of fibres that would inhibit the hardening of the lime. At last, with 3.39% ± 3.07% MPa, 2.27% ± 11.30% MPa for samples (A), (B) respectively, the minimum required by CRATerre-EAG (guide of CDI, 1996) for construction of envelope (walls) of single storey (ground floor) buildings is met.
基金Supported by the National Science and Technology (2006BAE03A11)the National Natural Science Foundation of China(50674062)
文摘The interaction of Si anions with Al sites during the hydration process was observed by NMR, IR and SEM to understand the reaction mechanism of the hydrates formation mixed with oil shale calcined at different temperatures. As the reaction progressed, the coordination of Al （Ⅳ, Ⅴ, and Ⅵ） changed almost completely to Ⅳ, when mixed with oil shale calcined at 700 ℃. However, when mixed with oil shale calcined at 400 ℃, some 6-coordination of Al still remained in the hydrates. Under the function of alkaline solutions, which were produced with the hydration of clinker, a certain amount of Si and Al atoms dissolved or hydrolyzed from aluminosilicate, formed geomonomers in solutions, and then polycondensed to form networks.
文摘Magnesia-calcium materials have stable hot performance,good resistance to the erosion and corrosion of liquid steel and steel slag,and a special role in purifying liquid steel,so they are widely used in iron and steel industry.However,hydration of magnesia-calcium materials seriously restricts their use,so researches have been done to improve their hydration resistance,obtaining a series of achievements.In this paper,the improvements on the hydration resistance of magnesia-calcium materials by additives in recent 20 years were presented,and their mechanisms were summarized.
基金supported by Iran National Science Foundation(INSF)under project No.4022382Facilities were provided by the Condensed Matter National Laboratory at the Institute for Research in Fundamental Sciences(IPM)in Tehran,Iran.Additionally,financial support for equipment purchase was granted by the INSF under project number 4022382.
文摘The rational design of high-performance electrochemical energy storage devices critically depends on a fundamental understanding of ion-electrode interactions at the molecular scale.Herein,we employ interpretable machine learning(ML)to reveal electrolyte hydration energy as a universal descriptor governing ion-specific capacitance in two-dimensional(2D)materials.Through explainable ML,we elucidate how ion hydration shell stability and size critically influence charge transport and storage at the electrode-electrolyte interface.Our analysis identifies hydration energy-not ionic size-as the primary factor dictating capacitance,challenging prevailing assumptions and providing quantifiable design rules for electrolyte selection.These insights offer a data-driven pathway to optimize 2D materials for supercapacitors and beyond,including batteries and electrocatalytic systems.This work demonstrates the power of explainable artificial intelligence in uncovering molecular-level mechanisms that accelerate the discovery and development of next-generation energy storage technologies.
基金Funded by the National Key Technology R&D Program in the12th Five Year Plan of China(No.2011BAE14B06)the National High Technology ResearchDevelopment Program of China(No.2015AA034701)
文摘Main performance of the cement grouting materials made up by Portland cement（PC） and sulphoaluminate cement（SAC） was investigated in this program, a kind of expanding agent（EA） which was mainly constituted by metakaolin and alunite was utilized for the compensation of the shrinkage, the hydration products and micro structure of the grouting materials were researched by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that a high expansion rate of the grouting materials could be reached as the expanding agent mixed in 6% of PC mass; the addition of SAC in the S2（PC：SAC：EA=34：6：2.25） brought a further improvement of the expansion rate of the grouting materials, the analysis of XRD and SEM showed that due to the reaction of expanding agent and SAC in the grouting materials, more ettringite crystal was generated, which resulted in a higher early strength, the addition of SAC played an expansion and strength reinforcement role in the grouting materials.
