This study presents a physics-informed modelling framework that combines finite element method(FEM)simulations and supervised machine learning(ML)to predict the self-healing performance of microbial concrete.A FEniCS-...This study presents a physics-informed modelling framework that combines finite element method(FEM)simulations and supervised machine learning(ML)to predict the self-healing performance of microbial concrete.A FEniCS-based FEM platform resolves multiphysics phenomena including nutrient diffusion,microbial CaCO_(3) precipitation,and stiffness recovery.These simulations,together with experimental data,are used to train ML models(Random Forest yielding normalized RMSE≈0.10)capable of predicting performance over a wide range of design parameters.Feature importance analysis identifies curing temperature,calcium carbonate precipitation rate,crack width,bacterial strain,and encapsulation method as the most influential parameters.The coupled FEM-ML approach enables sensitivity analysis,design optimization,and prediction beyond the training dataset(consistently exceeding 90%healing efficiency).Experimental validation confirms model robustness in both crack closure and strength recovery.This FEM–ML pipeline thus offers a generalizable,interpretable,and scalable strategy for the design of intelligent,self-adaptive construction materials.展开更多
Concrete production often relies on natural aggregates,which can lead to resource depletion and environmental harm.In addition,improper disposal of thermoplastic waste exacerbates ecological problems.Although signific...Concrete production often relies on natural aggregates,which can lead to resource depletion and environmental harm.In addition,improper disposal of thermoplastic waste exacerbates ecological problems.Although significant attention has recently been given to recycling various waste materials into concrete,studies specifically addressing thermoplastic recycled aggregates are still trending.This underscores the need to comprehensively review existing literature,identify research trends,and recognize gaps in understanding the mechanical performance of thermoplastic-based recycled aggregate concrete.Accordingly,this review summarizes recent investigations focused on the mechanical properties of thermoplastic-based recycled aggregate concrete,emphasizing aspects such as compressive strength,tensile behavior,modulus of elasticity,and durability characteristics.The primary aim is to consolidate scattered research findings,identify key parameters influencing mechanical behavior,and propose future research directions.Understanding the influence of recycled thermoplastic aggregates on concrete performance significantly supports sustainable construction practices by reducing dependency on virgin aggregates and mitigating environmental impacts associated with waste disposal.In addition,assessing mechanical performance contributes to confidence in the practical application,encouraging the broader adoption of thermoplastic-based recycled aggregate concrete in construction projects.Through this critical synthesis,the review guides researchers and industry practitioners toward informed decisions on the feasibility and reliability of integrating thermoplastic waste into concrete,thereby promoting sustainable infrastructure development.展开更多
This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw ...This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.展开更多
We investigated the effects of fly ash(FA)content on the mechanical properties of recycled aggregate concrete(RAC)and its regeneration potential under freeze and thaw(F-T)cycles.The physical properties of second-gener...We investigated the effects of fly ash(FA)content on the mechanical properties of recycled aggregate concrete(RAC)and its regeneration potential under freeze and thaw(F-T)cycles.The physical properties of second-generation recycled concrete aggregates(RCA)were used to analyze the regeneration potential of RAC after F-T cycles.Scanning electron microscopy was used to study the interfacial transition zone microstructure of RAC after F-T cycles.Results showed that adding 20%FA to RAC significantly enhanced its mechanical properties and frost resistance.Before the F-T cycles,the compressive strength of RAC with 20%FA reached 48.3 MPa,exceeding research strength target of 40 MPa.A majority of second-generation RCA with FA had been verified to attain class Ⅲ,which enabled their practical application in non-structural projects such as backfill trenches and road pavement.However,the second-generation RCA with 20%FA can achieve class Ⅱ,making it ideal for 40 MPa structural concrete.展开更多
The engineering application of low-alkali sulphoaluminate cement(L-SAC)is hindered due to the difficulty in adjusting the setting and hardening time.In this paper,lithium hydroxide and borax are mixed into L-SAC to re...The engineering application of low-alkali sulphoaluminate cement(L-SAC)is hindered due to the difficulty in adjusting the setting and hardening time.In this paper,lithium hydroxide and borax are mixed into L-SAC to regulate its setting and hardening process,so as to prepare a sulphoaluminate concrete material with high early strength and high fluidity.The effects of the ratio of lithium hydroxide to borax on the properties of L-SAC concrete were studied by hydration heat,XRD,TG-DTG,SEM and MIP.The experimental results show that the slump increases with the increase of borax content,and the early(3 h)strength increases with the increase of lithium hydroxide content.When 0.05% lithium hydroxide and 0.4% borax are added,the 0.5 h slump reaches 195 mm,and the 3 h compressive strength reaches 15.9 MPa.The increase of lithium hydroxide will promote the formation of early hydration products AFt and AH3 gel and accelerate the hydration process,while borax will inhibit the dissolution and hydration of cement and delay the setting and hardening process of concrete.The combination of the two ensures that the concrete has the characteristics of high early strength and high fluidity,and the early workability and mechanical properties can be controlled by the mix ratio.For long-term mechanical properties,the special concrete does not produce AFm,which can ensure the continuous development of strength.展开更多
Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse s...Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse shape,on achieving stress uniformity.After analysis,the paper provides actionable methods aimed at optimizing the conditions for stress uniformity within the cubic specimen.Finally,the lateral inertia effect of cubic specimen has been scrutinized to address the existing gap in this academic area.展开更多
Accurate prediction of concrete compressive strength is fundamental for optimizing mix designs,improving material utilization,and ensuring structural safety in modern construction.Traditional empirical methods often f...Accurate prediction of concrete compressive strength is fundamental for optimizing mix designs,improving material utilization,and ensuring structural safety in modern construction.Traditional empirical methods often fail to capture the non-linear relationships among concrete constituents,especially with the growing use of supple-mentary cementitious materials and recycled aggregates.This study presents an integrated machine learning framework for concrete strength prediction,combining advanced regression models—namely CatBoost—with metaheuristic optimization algorithms,with a particular focus on the Somersaulting Spider Optimizer(SSO).A comprehensive dataset encompassing diverse mix proportions and material types was used to evaluate baseline machine learning models,including CatBoost,XGBoost,ExtraTrees,and RandomForest.Among these,CatBoost demonstrated superior accuracy across multiple performance metrics.To further enhance predictive capability,several bio-inspired optimizers were employed for hyperparameter tuning.The SSO-CatBoost hybrid achieved the lowest mean squared error and highest correlation coefficients,outperforming other metaheuristic approaches such as Genetic Algorithm,Particle Swarm Optimization,and Grey Wolf Optimizer.Statistical significance was established through Analysis of Variance and Wilcoxon signed-rank testing,confirming the robustness of the optimized models.The proposed methodology not only delivers improved predictive performance but also offers a transparent framework for mix design optimization,supporting data-driven decision making in sustainable and resilient infrastructure development.展开更多
Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of re...Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of recycled coral aggregate on concrete properties,this study performed a comprehensive analysis of the physical properties of recycled coral aggregate and the basic mechanical properties and microstructure of RCAC.The test results indicate that,compared to coral debris,the crushing index of recycled coral aggregate was reduced by 9.4%,while porosity decreased by 33.5%.Furthermore,RCAC retained the early strength characteristics of coral concrete,with compressive strength and flexural strength exhibiting a notable increase as the water-cement ratio decreased.Under identical conditions,the compressive strength and flexural strength of RCAC were 12.7% and 2.5% higher than coral concrete's,respectively,with porosity correspondingly reduced from 3.13% to 5.11%.This enhancement could be attributed to the new mortar filling the recycled coral aggregate.Scanning electron microscopy(SEM)analysis revealed three distinct interface transition zones within RCAC,with the‘new mortar-old mortar’interface identified as the weakest.The above findings provided a reference for the sustainable use of coral concrete in constructing offshore islands.展开更多
This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways,aiming to support the development of concrete capable of withstanding higher ope...This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways,aiming to support the development of concrete capable of withstanding higher operational speeds.Fatigue tests were conducted at loading frequencies ranging from 5 to 40 Hz,with a focus on fatigue life,damage evolution,energy dissipation,and residual fatigue strain in the concrete.The results indicate that between 5 and 15 Hz,the fatigue life and energy dissipation remain relatively stable,with minimal damage evolution and small residual strains.As the frequency increases to 15-20 Hz,the fatigue life and energy dissipation gradually decrease,while damage accumulation and residual strain increase.Beyond 20 Hz,both fatigue life and energy dissipation decrease rapidly,damage accumulation becomes more pronounced,and residual strain continues to rise.These phenomena are primarily attributed to the increased strain rate and load change rate at higher frequencies,which affect the microstructure evolution and lead to reduced fatigue performance.展开更多
Conventional low-carbon concrete design approaches have often overlooked carbonation durability and the progressive loss of cover caused by surface scaling,both of which can increase the long-term risk of reinforcemen...Conventional low-carbon concrete design approaches have often overlooked carbonation durability and the progressive loss of cover caused by surface scaling,both of which can increase the long-term risk of reinforcement corrosion.To address these limitations,this study proposes an improved design framework for low-carbon slag concrete that simultaneously incorporates carbonation durability and cover scaling effects into the mix proportioning process.Based on experimental data,a linear predictive model was developed to estimate the 28-day compressive strength of slag concrete,achieving a correlation coefficient of R=0.87711 and a root mean square error(RMSE)of 7.55 MPa.The mechanism-based equation exhibits strong physical interpretability,as each parameter corresponds to a clear physical process,satisfying the requirements of design codes for physical significance.By integrating the strength and carbon-emission models,the carbon-emission efficiency was further analyzed.Across all water–binder ratios(0.3,0.4,0.5),CO_(2) emissions per unit strength decreased steadily with increasing slag content,indicating that carbon efficiency is primarily governed by slag replacement rather than the water/binder ratio.Four design cases,all with a design strength of 30 MPa,were then evaluated to illustrate the combined effects of carbonation and scaling.In Case 1,without considering carbonation durability,the carbonation depth after 50 years exceeded the 25 mm cover,leading to potential corrosion.In Case 2,when carbonation durability was considered,the required actual strength increased to 31.28 MPa.When mild cover scaling of 3 mm was introduced(Case 3),the required strength rose to 34.59 MPa,and under severe scaling of 10 mm(Case 4),it increased to 45.73 MPa.These results indicate that intensified scaling demands higher strength and lower water/binder ratios to maintain durability.Overall,the proposed framework quantitatively balances strength,durability,and embodied carbon,supporting sustainable low-carbon concrete design.展开更多
To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),supe...To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),super absorbent resin(SAP).The erosion mode and internal deterioration mechanism under salt freeze-thaw cycle and dry-wet cycle were explored.The results show that the addition of enhancing materials can effectively improve the resistance of concrete to salt freezing and sulfate erosion:the relevant indexes of concrete added with X-AP and T-AP are improved after salt freeze-thaw cycles;concrete added with SBTTIA shows optimal sulfate corrosion resistance;and concrete added with AP displays the best resistance to salt freezing.Microanalysis shows that the increase in the number of cycles decreases the generation of internal hydration products and defects in concrete mixed with enhancing materials and improves the related indexes.Based on the Wiener model analysis,the reliability of concrete with different lithologies and enhancing materials is improved,which may provide a reference for the application of manufactured sand concrete and enhancing materials in Northwest China,especially for the study of the improvement effects and mechanism of enhancing materials on the performance of concrete.展开更多
Unbonded post-tensioned(PT)concrete systems are widely used in safety-critical structures,yet model-ing practices for prestress implementation and tendon-concrete interaction remain inconsistent.This study investigate...Unbonded post-tensioned(PT)concrete systems are widely used in safety-critical structures,yet model-ing practices for prestress implementation and tendon-concrete interaction remain inconsistent.This study investigates the effects of sheath(duct)implementation and confinement assumptions through nonlinear finite element analysis.Four modeling cases were defined,consisting of an explicit sheath without tendon-concrete confinement(S)and three no-sheath variants with different confinement levels(X,N,A).One-way beams and two-way panels were analyzed,and panel blast responses were validated against experimental results.In both beams and panels,average initial stress levels were similar across models,through local stress concentrations appeared when the sheath was modeled.Under blast loading,these local effects became critical,and the sheath-implemented model reproduced experimental behavior most accurately,whereas non-implemented models deviated.Reduced blast intensity diminished the differences among models,thereby reaffirming that sheath-induced localization and damage propagation are critical factors.These findings highlight the importance of explicit sheath implementation for realistic numerical assessment of unbonded PT structures under extreme loads.展开更多
In modern construction,Lightweight Aggregate Concrete(LWAC)has been recognized as a vital material of concern because of its unique properties,such as reduced density and improved thermal insulation.Despite the extens...In modern construction,Lightweight Aggregate Concrete(LWAC)has been recognized as a vital material of concern because of its unique properties,such as reduced density and improved thermal insulation.Despite the extensive knowledge regarding its macroscopic properties,there is a wide knowledge gap in understanding the influence of microscale parameters like aggregate porosity and volume ratio on the mechanical response of LWAC.This study aims to bridge this knowledge gap,spurred by the need to enhance the predictability and applicability of LWAC in various construction environments.With the help of advanced numerical methods,including the finite element method and a random circular aggregate model,this study critically evaluates the role played by these microscale factors.We found that an increase in the aggregate porosity from 23.5%to 48.5%leads to a drastic change of weakness from the bonding interface to the aggregate,reducing compressive strength by up to 24.2%and tensile strength by 27.8%.Similarly,the increase in the volume ratio of lightweight aggregate from 25%to 40%leads to a reduction in compressive strength by 13.0%and tensile strength by 9.23%.These results highlight the imperative role of microscale properties on the mechanical properties of LWAC.By supplying precise quantitative details on the effect of porosity and aggregate volume ratio,this research makes significant contributions to construction materials science by providing useful recommendations for the creation and optimization of LWAC with improved performance and sustainability in construction.展开更多
This study investigates the thermo–mechanical behavior of C40 concrete and reinforced concrete subjected to elevated temperatures up to 700℃by integrating experimental testing and advanced numerical modeling.A tempe...This study investigates the thermo–mechanical behavior of C40 concrete and reinforced concrete subjected to elevated temperatures up to 700℃by integrating experimental testing and advanced numerical modeling.A temperature-indexed Concrete Damage Plasticity(CDP)framework incorporating bond–slip effects was developed in Abaqus to capture both global stress–strain responses and localized damage evolution.Uniaxial compression tests on thermally exposed cylinders provided residual strength data and failure observations for model calibration and validation.Results demonstrated a distinct two-stage degradation regime:moderate stiffness and strength reduction up to~400℃,followed by sharp deterioration beyond 500℃–600℃,with residual capacity at 700℃reduced to~20%–25%of the ambient value.Strain–damage analyses revealed the formation of a peripheral tensile strain band,which thickened and propagated inward with increasing temperature,governing crack initiation and cover spalling.Supplemental analyses highlighted that transverse reinforcement improved ductility and damage distribution at moderate temperatures(~300℃),but bond deterioration and steel softening beyond~600℃substantially diminished confinement effectiveness.The proposed CDP model accurately reproduced experimental stress–strain curves(R^(2)≈0.94–0.98 up to 600℃;≈0.90 at 700℃),with peak stress errors within 7%–10%and energy absorption captured within~12%.These findings confirm the robustness of the temperature-indexed CDP framework for simulating fire-damaged reinforced concrete and provide practical guidelines for post-fire assessment,spalling detection,and fire-resilient design of structural members.展开更多
The current technical standards primarily relied on experience to judge the interfacial bonding properties between the self-compacting concrete filling layer and the steam-cured concrete precast slab in CRTS Ⅲ slab b...The current technical standards primarily relied on experience to judge the interfacial bonding properties between the self-compacting concrete filling layer and the steam-cured concrete precast slab in CRTS Ⅲ slab ballastless track structure.This study sought to enhance technical standards for evaluating interfacial bonding properties by suggesting the use of the splitting tensile strength to evaluate the impact of bubble defects.Specimens were fabricated through on-site experiment.The percent of each area of 6 cm^(2)or more bubble defect was 0 in most of specimens.When the cumulative area of all bub-ble defects reached 12%,the splitting tensile strength value was 0.67 MPa,which exceeded the minimum required value of 0.5 MPa for ensuring bonding interface adhesion.Furthermore,when the cumulative area of all bubble defects reached 8%,the splitting tensile strength value was 0.85 MPa,which exceeded the minimum required value of 0.8 MPa,thereby over-coming the negative impact of each area of 10 cm^(2) or more bubble defect.Additionally,keeping the cumulative area of each area of 6 cm^(2) or more bubble defect below 6%ensured adequate bonding strength and reduced the occurrence of specimens with lower splitting tensile strength values.展开更多
Many hydropower projects have been constructed in Southwest China with the strategic goal of achieving carbon neutrality.Most of these hydropower projects utilize concrete face rockfilldams(CFRDs)built on a deep overb...Many hydropower projects have been constructed in Southwest China with the strategic goal of achieving carbon neutrality.Most of these hydropower projects utilize concrete face rockfilldams(CFRDs)built on a deep overburden layer.The deep overburden layer causes uneven settlement between the overburden layer and the dam,which poses a serious threat to the safety of both the construction and operation of the dam.In this study,microseismic(MS)monitoring technology was employed for the firsttime in the fieldof dam fillingengineering,allowing for the real-time monitoring of microfracture in the bedrock during dam construction.The time-frequency analysis method was used to summarize the MS waveform characteristics induced by dam filling.The fracture mechanism of bedrock was revealed,and the relationships among slope deformation,dam settlement,and MS activity were analyzed.The following research results have been obtained.The MS signal induced by dam fillinghas low energy and amplitude,short duration,and high frequency.The fracture of the bedrock was mainly shear failure.MS monitoring can predict deformation during blasting excavation and capture the large settlement that may occur during dam fillingin advance.Research findingshave demonstrated the significantapplication value of MS monitoring technology in predicting the risk of dam settlement and provide a reference for similar projects.展开更多
The detection of surface defects in concrete bridges using deep learning is of significant importance for reducing operational risks,saving maintenance costs,and driving the intelligent transformation of bridge defect...The detection of surface defects in concrete bridges using deep learning is of significant importance for reducing operational risks,saving maintenance costs,and driving the intelligent transformation of bridge defect detection.In contrast to the subjective and inefficient manual visual inspection,deep learning-based algorithms for concrete defect detection exhibit remarkable advantages,emerging as a focal point in recent research.This paper comprehensively analyzes the research progress of deep learning algorithms in the field of surface defect detection in concrete bridges in recent years.It introduces the early detection methods for surface defects in concrete bridges and the development of deep learning.Subsequently,it provides an overview of deep learning-based concrete bridge surface defect detection research from three aspects:image classification,object detection,and semantic segmentation.The paper summarizes the strengths and weaknesses of existing methods and the challenges they face.Additionally,it analyzes and prospects the development trends of surface defect detection in concrete bridges.展开更多
Marine infrastructure is increasingly vulnerable to harsh environmental conditions that accelerate the degradation of traditional materials such as Portland cement concrete and carbon steel.This review systematically ...Marine infrastructure is increasingly vulnerable to harsh environmental conditions that accelerate the degradation of traditional materials such as Portland cement concrete and carbon steel.This review systematically investigates recent advancements in sustainable alternatives,including geopolymer concrete,engineered innovacementitious composites(ECC),bio-concrete,fiber-reinforced polymers(FRPs),and bamboo,stainless steel,and steel-CFRP hybrid bars.Each material is evaluated based on marine durability,mechanical performance,environmental impact,and cost feasibility using life cycle assessment,durability modelling,and a multi-criteria decisionsupport framework.The results reveal that geopolymer concrete and FRP reinforcement’s exhibit superior corrosion resistance and environmental benefits,while ECC and steel-CFRP composites offer structural resilience with moderate environmental trade-offs.However,challenges remain in long-term performance validation,standardization,and market integration.The review concludes that a combined approach involving innovative materials,computational tools,and sustainability assessment is essential for advancing marine infrastructure.Outlook recommendations include focused field studies,development of regulatory guidelines,and interdisciplinary collaboration to drive the practical adoption of eco-efficient materials in coastal and offshore construction.展开更多
When the upper chord beam of the beam-string structure(BSS)is made of concrete-filled steel tube(CFST),its overall stiffness will change greatly with the construction of concrete placement,which will have an impact on ...When the upper chord beam of the beam-string structure(BSS)is made of concrete-filled steel tube(CFST),its overall stiffness will change greatly with the construction of concrete placement,which will have an impact on the design of the tensioning plans and selection of control measures for the BSS.In order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of composite BSS during con-struction,the influence of some factors such as height-width ratio,wall thickness of steel tube,elasticity modulus of concrete,and friction coefficient on the bending stiffness are analyzed parametrically by the numerical simula-tion technology based on an actual project.The calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical simulation.Then,the equivalent bending stiffness is introduced into the construction and use stages of the composite BSS,respectively,and the mechanical properties such as prestress-tensioning control value,structural deformation,and internal force of key members are comparatively analyzed when adopting two different construction plans.Moreover,the optimal construction plan of concrete placementfirst and then prestress-tensioning is proposed.展开更多
Concrete is one of the key component in the construction field.The importance of concrete is because of its strength and long lasting properties.The incorporation of nano materials in concrete helps to improve the cha...Concrete is one of the key component in the construction field.The importance of concrete is because of its strength and long lasting properties.The incorporation of nano materials in concrete helps to improve the characteristics of conventional concrete.Titanium dioxide(TiO_(2))is one such nanomaterial that helps to increase the performance of concrete by enhancing self-cleaning,anti-microbial and anti-bacterial activities.This paper briefly explains about the reaction of titanium dioxide nano particle N-TiO_(2) on cement materials which in turn changes the mechanical and physical properties of concrete against chemical,climatic changes and abrasion.The review presented here includes the features of titanium dioxide nano particles basically,its dosage in concrete,its impact on concrete on both fresh and hardened properties,photo catalytic effect and anti-microbial.This review explores the photo catalytic degradation of concrete enhanced with N-TiO_(2),which presents a promising method for improving the durability and sustainability of concrete structures.The addition of N-TiO_(2),recognized for its photo catalytic properties when exposed to UV light,has demonstrated potential in tackling various environmental and structural challenges associated with concrete.The paper provides a detailed analysis of the mechanisms involved in the photo catalytic process,the way N-TiO_(2) particles aid in breaking down pollutants(including organic compounds,NOx,and CO₂),and its contributions to self-cleaning,antimicrobial functions,and the degradation of harmful pollutants.展开更多
基金funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Grant Agreement No.945478(SASPRO2)supported by the ReBuilt project:Circular and Digital Renewal of Central Europe Construction and Building Sector CE0100390 ReBuiltthe Slovak Research and Development Agency under APVV-23-0383 and the Slovak Grant Agency VEGA No.2/0080/24.
文摘This study presents a physics-informed modelling framework that combines finite element method(FEM)simulations and supervised machine learning(ML)to predict the self-healing performance of microbial concrete.A FEniCS-based FEM platform resolves multiphysics phenomena including nutrient diffusion,microbial CaCO_(3) precipitation,and stiffness recovery.These simulations,together with experimental data,are used to train ML models(Random Forest yielding normalized RMSE≈0.10)capable of predicting performance over a wide range of design parameters.Feature importance analysis identifies curing temperature,calcium carbonate precipitation rate,crack width,bacterial strain,and encapsulation method as the most influential parameters.The coupled FEM-ML approach enables sensitivity analysis,design optimization,and prediction beyond the training dataset(consistently exceeding 90%healing efficiency).Experimental validation confirms model robustness in both crack closure and strength recovery.This FEM–ML pipeline thus offers a generalizable,interpretable,and scalable strategy for the design of intelligent,self-adaptive construction materials.
文摘Concrete production often relies on natural aggregates,which can lead to resource depletion and environmental harm.In addition,improper disposal of thermoplastic waste exacerbates ecological problems.Although significant attention has recently been given to recycling various waste materials into concrete,studies specifically addressing thermoplastic recycled aggregates are still trending.This underscores the need to comprehensively review existing literature,identify research trends,and recognize gaps in understanding the mechanical performance of thermoplastic-based recycled aggregate concrete.Accordingly,this review summarizes recent investigations focused on the mechanical properties of thermoplastic-based recycled aggregate concrete,emphasizing aspects such as compressive strength,tensile behavior,modulus of elasticity,and durability characteristics.The primary aim is to consolidate scattered research findings,identify key parameters influencing mechanical behavior,and propose future research directions.Understanding the influence of recycled thermoplastic aggregates on concrete performance significantly supports sustainable construction practices by reducing dependency on virgin aggregates and mitigating environmental impacts associated with waste disposal.In addition,assessing mechanical performance contributes to confidence in the practical application,encouraging the broader adoption of thermoplastic-based recycled aggregate concrete in construction projects.Through this critical synthesis,the review guides researchers and industry practitioners toward informed decisions on the feasibility and reliability of integrating thermoplastic waste into concrete,thereby promoting sustainable infrastructure development.
基金Funded by the Science and Technology Program of Gansu Province(Nos.25JRRA497,23ZDFA017)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0950000)High-level Talent Funding of Kashi。
文摘This study introduces superabsorbent polymers(SAP)into recycled concrete and,through freeze-thaw cycle tests,unconfined compressive strength tests,and nuclear magnetic resonance(NMR)analysis,evaluates the freeze-thaw resistance and durability of recycled concrete samples under varying freeze-thaw cycles.The results indicate that an appropriate addition of SAP significantly enhances the freeze-thaw resistance of recycled concrete.After 200 freeze-thaw cycles,the RS0.6 sample retained good surface integrity,demonstrating the best performance.Compared to NAC,its mass loss decreased by 1.16%,the relative dynamic modulus improved by 7.01%,and the compressive strength loss rate decreased by 5.41%.Additionally,T2 spectrum analysis revealed that adding SAP optimized the pore structure of recycled concrete and mitigated pore development during freeze-thaw cycles.As the number of freeze-thaw cycles increased,the RS0.3 and RS0.6 samples demonstrated superior frost resistance compared to NAC.However,an excessive amount of SAP increased pore expansion during subsequent freeze-thaw cycles,ultimately weakening frost resistance.
基金Funded by the Natural Science Foundation of Jiangsu Province(No.BK20220626)the National Natural Science Foundation of China(No.52078068)+2 种基金Science and Technology Innovation Foundation of NIT(No.KCTD006)Jiangsu Marine Structure Service Performance Improvement Engineering Research CenterKey Laboratory of Jiangsu"Marine Floating Wind Power Technology and Equipment"。
文摘We investigated the effects of fly ash(FA)content on the mechanical properties of recycled aggregate concrete(RAC)and its regeneration potential under freeze and thaw(F-T)cycles.The physical properties of second-generation recycled concrete aggregates(RCA)were used to analyze the regeneration potential of RAC after F-T cycles.Scanning electron microscopy was used to study the interfacial transition zone microstructure of RAC after F-T cycles.Results showed that adding 20%FA to RAC significantly enhanced its mechanical properties and frost resistance.Before the F-T cycles,the compressive strength of RAC with 20%FA reached 48.3 MPa,exceeding research strength target of 40 MPa.A majority of second-generation RCA with FA had been verified to attain class Ⅲ,which enabled their practical application in non-structural projects such as backfill trenches and road pavement.However,the second-generation RCA with 20%FA can achieve class Ⅱ,making it ideal for 40 MPa structural concrete.
基金Funded by the National Natural Science Foundation of China(No.52568032)Guangxi Key Research and Development Program(GKNos.AB24010020,AB23026071,and AD24010062)。
文摘The engineering application of low-alkali sulphoaluminate cement(L-SAC)is hindered due to the difficulty in adjusting the setting and hardening time.In this paper,lithium hydroxide and borax are mixed into L-SAC to regulate its setting and hardening process,so as to prepare a sulphoaluminate concrete material with high early strength and high fluidity.The effects of the ratio of lithium hydroxide to borax on the properties of L-SAC concrete were studied by hydration heat,XRD,TG-DTG,SEM and MIP.The experimental results show that the slump increases with the increase of borax content,and the early(3 h)strength increases with the increase of lithium hydroxide content.When 0.05% lithium hydroxide and 0.4% borax are added,the 0.5 h slump reaches 195 mm,and the 3 h compressive strength reaches 15.9 MPa.The increase of lithium hydroxide will promote the formation of early hydration products AFt and AH3 gel and accelerate the hydration process,while borax will inhibit the dissolution and hydration of cement and delay the setting and hardening process of concrete.The combination of the two ensures that the concrete has the characteristics of high early strength and high fluidity,and the early workability and mechanical properties can be controlled by the mix ratio.For long-term mechanical properties,the special concrete does not produce AFm,which can ensure the continuous development of strength.
基金Funded by the National Natural Science Foundation of China(Nos.52278518 and 51938011)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.24KJB560021)。
文摘Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse shape,on achieving stress uniformity.After analysis,the paper provides actionable methods aimed at optimizing the conditions for stress uniformity within the cubic specimen.Finally,the lateral inertia effect of cubic specimen has been scrutinized to address the existing gap in this academic area.
文摘Accurate prediction of concrete compressive strength is fundamental for optimizing mix designs,improving material utilization,and ensuring structural safety in modern construction.Traditional empirical methods often fail to capture the non-linear relationships among concrete constituents,especially with the growing use of supple-mentary cementitious materials and recycled aggregates.This study presents an integrated machine learning framework for concrete strength prediction,combining advanced regression models—namely CatBoost—with metaheuristic optimization algorithms,with a particular focus on the Somersaulting Spider Optimizer(SSO).A comprehensive dataset encompassing diverse mix proportions and material types was used to evaluate baseline machine learning models,including CatBoost,XGBoost,ExtraTrees,and RandomForest.Among these,CatBoost demonstrated superior accuracy across multiple performance metrics.To further enhance predictive capability,several bio-inspired optimizers were employed for hyperparameter tuning.The SSO-CatBoost hybrid achieved the lowest mean squared error and highest correlation coefficients,outperforming other metaheuristic approaches such as Genetic Algorithm,Particle Swarm Optimization,and Grey Wolf Optimizer.Statistical significance was established through Analysis of Variance and Wilcoxon signed-rank testing,confirming the robustness of the optimized models.The proposed methodology not only delivers improved predictive performance but also offers a transparent framework for mix design optimization,supporting data-driven decision making in sustainable and resilient infrastructure development.
基金Funded by Natural Science Foundation of Guangxi(No.2025GXNSFBA069565)Guangxi Science and Technology Program(No.AD25069101)Guangxi Bagui Scholars Fund。
文摘Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of recycled coral aggregate on concrete properties,this study performed a comprehensive analysis of the physical properties of recycled coral aggregate and the basic mechanical properties and microstructure of RCAC.The test results indicate that,compared to coral debris,the crushing index of recycled coral aggregate was reduced by 9.4%,while porosity decreased by 33.5%.Furthermore,RCAC retained the early strength characteristics of coral concrete,with compressive strength and flexural strength exhibiting a notable increase as the water-cement ratio decreased.Under identical conditions,the compressive strength and flexural strength of RCAC were 12.7% and 2.5% higher than coral concrete's,respectively,with porosity correspondingly reduced from 3.13% to 5.11%.This enhancement could be attributed to the new mortar filling the recycled coral aggregate.Scanning electron microscopy(SEM)analysis revealed three distinct interface transition zones within RCAC,with the‘new mortar-old mortar’interface identified as the weakest.The above findings provided a reference for the sustainable use of coral concrete in constructing offshore islands.
基金sponsored by the National Natural Science Foundation of China(Grant No.52438002)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘This study investigates the influence of loading frequency on the fatigue behavior of ballastless track concrete for high-speed railways,aiming to support the development of concrete capable of withstanding higher operational speeds.Fatigue tests were conducted at loading frequencies ranging from 5 to 40 Hz,with a focus on fatigue life,damage evolution,energy dissipation,and residual fatigue strain in the concrete.The results indicate that between 5 and 15 Hz,the fatigue life and energy dissipation remain relatively stable,with minimal damage evolution and small residual strains.As the frequency increases to 15-20 Hz,the fatigue life and energy dissipation gradually decrease,while damage accumulation and residual strain increase.Beyond 20 Hz,both fatigue life and energy dissipation decrease rapidly,damage accumulation becomes more pronounced,and residual strain continues to rise.These phenomena are primarily attributed to the increased strain rate and load change rate at higher frequencies,which affect the microstructure evolution and lead to reduced fatigue performance.
基金supported by the National Natural Science Foundation of China(No.52463034)supported by the Korea Institute of Energy Technology Evaluation and Planning funded by the Ministry of Trade,Industry and Energy(No.2025-02314098)of the Republic of Koreasupported by the Regional Innovation System&Education(RISE)program through the Gangwon RISE Center,funded by the Ministry of Education(MOE)and the Gangwon State(G.S.),Republic of Korea(2025-RISE-10-002).
文摘Conventional low-carbon concrete design approaches have often overlooked carbonation durability and the progressive loss of cover caused by surface scaling,both of which can increase the long-term risk of reinforcement corrosion.To address these limitations,this study proposes an improved design framework for low-carbon slag concrete that simultaneously incorporates carbonation durability and cover scaling effects into the mix proportioning process.Based on experimental data,a linear predictive model was developed to estimate the 28-day compressive strength of slag concrete,achieving a correlation coefficient of R=0.87711 and a root mean square error(RMSE)of 7.55 MPa.The mechanism-based equation exhibits strong physical interpretability,as each parameter corresponds to a clear physical process,satisfying the requirements of design codes for physical significance.By integrating the strength and carbon-emission models,the carbon-emission efficiency was further analyzed.Across all water–binder ratios(0.3,0.4,0.5),CO_(2) emissions per unit strength decreased steadily with increasing slag content,indicating that carbon efficiency is primarily governed by slag replacement rather than the water/binder ratio.Four design cases,all with a design strength of 30 MPa,were then evaluated to illustrate the combined effects of carbonation and scaling.In Case 1,without considering carbonation durability,the carbonation depth after 50 years exceeded the 25 mm cover,leading to potential corrosion.In Case 2,when carbonation durability was considered,the required actual strength increased to 31.28 MPa.When mild cover scaling of 3 mm was introduced(Case 3),the required strength rose to 34.59 MPa,and under severe scaling of 10 mm(Case 4),it increased to 45.73 MPa.These results indicate that intensified scaling demands higher strength and lower water/binder ratios to maintain durability.Overall,the proposed framework quantitatively balances strength,durability,and embodied carbon,supporting sustainable low-carbon concrete design.
基金Funded by the National Natural Science Foundation of China(No.52178216)the Research on the Durability and Application of High-performance Concrete for Highway Engineering in the Cold and Arid Salt Areas of Northwest China(No.2022-24)the Construction Project of the Scientific Research Platform of Provincial Enterprises Supported by the Capital Operating Budget of Gansu Province(No.2023GZ018)。
文摘To study the durability of concrete in harsh environments in Northwest China,concrete was prepared with various durability-improving materials such as concrete anti-erosion inhibitor(SBT-TIA),acrylate polymer(AP),super absorbent resin(SAP).The erosion mode and internal deterioration mechanism under salt freeze-thaw cycle and dry-wet cycle were explored.The results show that the addition of enhancing materials can effectively improve the resistance of concrete to salt freezing and sulfate erosion:the relevant indexes of concrete added with X-AP and T-AP are improved after salt freeze-thaw cycles;concrete added with SBTTIA shows optimal sulfate corrosion resistance;and concrete added with AP displays the best resistance to salt freezing.Microanalysis shows that the increase in the number of cycles decreases the generation of internal hydration products and defects in concrete mixed with enhancing materials and improves the related indexes.Based on the Wiener model analysis,the reliability of concrete with different lithologies and enhancing materials is improved,which may provide a reference for the application of manufactured sand concrete and enhancing materials in Northwest China,especially for the study of the improvement effects and mechanism of enhancing materials on the performance of concrete.
基金supported by the Nuclear Safety Research Program through the Korea Foundation of Nuclear Safety(KoFONS)using the financial resource granted by the Nuclear Safety and Security Commission(NSSC)of the Republic of Korea[RS-2025-02310881]the Korea Institute of Energy Technology Evaluation and Planning[KETEP]grant funded by the Ministry of Trade,Industry and Energy(MOTIE)[RS-2025-25447272].
文摘Unbonded post-tensioned(PT)concrete systems are widely used in safety-critical structures,yet model-ing practices for prestress implementation and tendon-concrete interaction remain inconsistent.This study investigates the effects of sheath(duct)implementation and confinement assumptions through nonlinear finite element analysis.Four modeling cases were defined,consisting of an explicit sheath without tendon-concrete confinement(S)and three no-sheath variants with different confinement levels(X,N,A).One-way beams and two-way panels were analyzed,and panel blast responses were validated against experimental results.In both beams and panels,average initial stress levels were similar across models,through local stress concentrations appeared when the sheath was modeled.Under blast loading,these local effects became critical,and the sheath-implemented model reproduced experimental behavior most accurately,whereas non-implemented models deviated.Reduced blast intensity diminished the differences among models,thereby reaffirming that sheath-induced localization and damage propagation are critical factors.These findings highlight the importance of explicit sheath implementation for realistic numerical assessment of unbonded PT structures under extreme loads.
基金supported by National Science Foundation of China(10972015,11172015)the Beijing Natural Science Foundation(8162008).
文摘In modern construction,Lightweight Aggregate Concrete(LWAC)has been recognized as a vital material of concern because of its unique properties,such as reduced density and improved thermal insulation.Despite the extensive knowledge regarding its macroscopic properties,there is a wide knowledge gap in understanding the influence of microscale parameters like aggregate porosity and volume ratio on the mechanical response of LWAC.This study aims to bridge this knowledge gap,spurred by the need to enhance the predictability and applicability of LWAC in various construction environments.With the help of advanced numerical methods,including the finite element method and a random circular aggregate model,this study critically evaluates the role played by these microscale factors.We found that an increase in the aggregate porosity from 23.5%to 48.5%leads to a drastic change of weakness from the bonding interface to the aggregate,reducing compressive strength by up to 24.2%and tensile strength by 27.8%.Similarly,the increase in the volume ratio of lightweight aggregate from 25%to 40%leads to a reduction in compressive strength by 13.0%and tensile strength by 9.23%.These results highlight the imperative role of microscale properties on the mechanical properties of LWAC.By supplying precise quantitative details on the effect of porosity and aggregate volume ratio,this research makes significant contributions to construction materials science by providing useful recommendations for the creation and optimization of LWAC with improved performance and sustainability in construction.
文摘This study investigates the thermo–mechanical behavior of C40 concrete and reinforced concrete subjected to elevated temperatures up to 700℃by integrating experimental testing and advanced numerical modeling.A temperature-indexed Concrete Damage Plasticity(CDP)framework incorporating bond–slip effects was developed in Abaqus to capture both global stress–strain responses and localized damage evolution.Uniaxial compression tests on thermally exposed cylinders provided residual strength data and failure observations for model calibration and validation.Results demonstrated a distinct two-stage degradation regime:moderate stiffness and strength reduction up to~400℃,followed by sharp deterioration beyond 500℃–600℃,with residual capacity at 700℃reduced to~20%–25%of the ambient value.Strain–damage analyses revealed the formation of a peripheral tensile strain band,which thickened and propagated inward with increasing temperature,governing crack initiation and cover spalling.Supplemental analyses highlighted that transverse reinforcement improved ductility and damage distribution at moderate temperatures(~300℃),but bond deterioration and steel softening beyond~600℃substantially diminished confinement effectiveness.The proposed CDP model accurately reproduced experimental stress–strain curves(R^(2)≈0.94–0.98 up to 600℃;≈0.90 at 700℃),with peak stress errors within 7%–10%and energy absorption captured within~12%.These findings confirm the robustness of the temperature-indexed CDP framework for simulating fire-damaged reinforced concrete and provide practical guidelines for post-fire assessment,spalling detection,and fire-resilient design of structural members.
基金supported by a grant from China railway corporation science and technology research and development plan project(Grant No.2017G005-B)funding support by Wuyi University’s Hong Kong and Macao Joint Research and Development Fund(Grants No.2021WGALH15)funding support by the Innovation and Technology Commission of Hong Kong SAR Government to the Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center(Grant No.K-BBY1).
文摘The current technical standards primarily relied on experience to judge the interfacial bonding properties between the self-compacting concrete filling layer and the steam-cured concrete precast slab in CRTS Ⅲ slab ballastless track structure.This study sought to enhance technical standards for evaluating interfacial bonding properties by suggesting the use of the splitting tensile strength to evaluate the impact of bubble defects.Specimens were fabricated through on-site experiment.The percent of each area of 6 cm^(2)or more bubble defect was 0 in most of specimens.When the cumulative area of all bub-ble defects reached 12%,the splitting tensile strength value was 0.67 MPa,which exceeded the minimum required value of 0.5 MPa for ensuring bonding interface adhesion.Furthermore,when the cumulative area of all bubble defects reached 8%,the splitting tensile strength value was 0.85 MPa,which exceeded the minimum required value of 0.8 MPa,thereby over-coming the negative impact of each area of 10 cm^(2) or more bubble defect.Additionally,keeping the cumulative area of each area of 6 cm^(2) or more bubble defect below 6%ensured adequate bonding strength and reduced the occurrence of specimens with lower splitting tensile strength values.
基金support from the Joint Funds of the National Natural Science Foundation of China(Grant No.42177143)the National Natural Science Foundation of China(Grant No.U23A2060).
文摘Many hydropower projects have been constructed in Southwest China with the strategic goal of achieving carbon neutrality.Most of these hydropower projects utilize concrete face rockfilldams(CFRDs)built on a deep overburden layer.The deep overburden layer causes uneven settlement between the overburden layer and the dam,which poses a serious threat to the safety of both the construction and operation of the dam.In this study,microseismic(MS)monitoring technology was employed for the firsttime in the fieldof dam fillingengineering,allowing for the real-time monitoring of microfracture in the bedrock during dam construction.The time-frequency analysis method was used to summarize the MS waveform characteristics induced by dam filling.The fracture mechanism of bedrock was revealed,and the relationships among slope deformation,dam settlement,and MS activity were analyzed.The following research results have been obtained.The MS signal induced by dam fillinghas low energy and amplitude,short duration,and high frequency.The fracture of the bedrock was mainly shear failure.MS monitoring can predict deformation during blasting excavation and capture the large settlement that may occur during dam fillingin advance.Research findingshave demonstrated the significantapplication value of MS monitoring technology in predicting the risk of dam settlement and provide a reference for similar projects.
基金supported by the Key Research and Development Program of Shaanxi Province-International Science and Technology Cooperation Program Project (No.2020KW-001)the Contract for Xi'an Municipal Science and Technology Plan Project-Xi'an City Strong Foundation Innovation Plan (No.21XJZZ0074)the Key Project of Graduate Student Innovation Fund at Xi'an University of Posts and Telecommunications (No.CXJJZL2023013)。
文摘The detection of surface defects in concrete bridges using deep learning is of significant importance for reducing operational risks,saving maintenance costs,and driving the intelligent transformation of bridge defect detection.In contrast to the subjective and inefficient manual visual inspection,deep learning-based algorithms for concrete defect detection exhibit remarkable advantages,emerging as a focal point in recent research.This paper comprehensively analyzes the research progress of deep learning algorithms in the field of surface defect detection in concrete bridges in recent years.It introduces the early detection methods for surface defects in concrete bridges and the development of deep learning.Subsequently,it provides an overview of deep learning-based concrete bridge surface defect detection research from three aspects:image classification,object detection,and semantic segmentation.The paper summarizes the strengths and weaknesses of existing methods and the challenges they face.Additionally,it analyzes and prospects the development trends of surface defect detection in concrete bridges.
文摘Marine infrastructure is increasingly vulnerable to harsh environmental conditions that accelerate the degradation of traditional materials such as Portland cement concrete and carbon steel.This review systematically investigates recent advancements in sustainable alternatives,including geopolymer concrete,engineered innovacementitious composites(ECC),bio-concrete,fiber-reinforced polymers(FRPs),and bamboo,stainless steel,and steel-CFRP hybrid bars.Each material is evaluated based on marine durability,mechanical performance,environmental impact,and cost feasibility using life cycle assessment,durability modelling,and a multi-criteria decisionsupport framework.The results reveal that geopolymer concrete and FRP reinforcement’s exhibit superior corrosion resistance and environmental benefits,while ECC and steel-CFRP composites offer structural resilience with moderate environmental trade-offs.However,challenges remain in long-term performance validation,standardization,and market integration.The review concludes that a combined approach involving innovative materials,computational tools,and sustainability assessment is essential for advancing marine infrastructure.Outlook recommendations include focused field studies,development of regulatory guidelines,and interdisciplinary collaboration to drive the practical adoption of eco-efficient materials in coastal and offshore construction.
基金supported by the Project on Excellent Post-Graduate Dissertation of Hohai University,Nanjing,China(422003508)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(SJCX23_0187+2 种基金422003287)the National Natural Science Foundation of China(52250410359)Young Elite Scientists Sponsorship Program by Jiangsu Provincial Association for Science and Technology(TJ-2023-043).
文摘When the upper chord beam of the beam-string structure(BSS)is made of concrete-filled steel tube(CFST),its overall stiffness will change greatly with the construction of concrete placement,which will have an impact on the design of the tensioning plans and selection of control measures for the BSS.In order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of composite BSS during con-struction,the influence of some factors such as height-width ratio,wall thickness of steel tube,elasticity modulus of concrete,and friction coefficient on the bending stiffness are analyzed parametrically by the numerical simula-tion technology based on an actual project.The calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical simulation.Then,the equivalent bending stiffness is introduced into the construction and use stages of the composite BSS,respectively,and the mechanical properties such as prestress-tensioning control value,structural deformation,and internal force of key members are comparatively analyzed when adopting two different construction plans.Moreover,the optimal construction plan of concrete placementfirst and then prestress-tensioning is proposed.
文摘Concrete is one of the key component in the construction field.The importance of concrete is because of its strength and long lasting properties.The incorporation of nano materials in concrete helps to improve the characteristics of conventional concrete.Titanium dioxide(TiO_(2))is one such nanomaterial that helps to increase the performance of concrete by enhancing self-cleaning,anti-microbial and anti-bacterial activities.This paper briefly explains about the reaction of titanium dioxide nano particle N-TiO_(2) on cement materials which in turn changes the mechanical and physical properties of concrete against chemical,climatic changes and abrasion.The review presented here includes the features of titanium dioxide nano particles basically,its dosage in concrete,its impact on concrete on both fresh and hardened properties,photo catalytic effect and anti-microbial.This review explores the photo catalytic degradation of concrete enhanced with N-TiO_(2),which presents a promising method for improving the durability and sustainability of concrete structures.The addition of N-TiO_(2),recognized for its photo catalytic properties when exposed to UV light,has demonstrated potential in tackling various environmental and structural challenges associated with concrete.The paper provides a detailed analysis of the mechanisms involved in the photo catalytic process,the way N-TiO_(2) particles aid in breaking down pollutants(including organic compounds,NOx,and CO₂),and its contributions to self-cleaning,antimicrobial functions,and the degradation of harmful pollutants.
