Design Life Research Articles

Effect of scour on the fatigue life of offshore wind turbines and its prevention through passive structural control

Abstract. Offshore wind turbine (OWT) support structures are exposed to the risk of fatigue damage and scour, and this risk can be effectively mitigated by installing structural control devices such as tuned mass dampers (TMDs). However, time-varying scour altering OWTs' dynamic characteristics has an impact on the TMD design and fatigue life, which has rarely been studied before. In this paper, a simplified modal model is used to investigate the influence of scour and a TMD on the fatigue life evaluation of a 5 MW OWT's support structure, and a traditional method and a newly developed optimization technique are both presented to obtain TMD parameters. This optimization technique aims at finding optimal parameters of the TMD which maximize the fatigue life of a hotspot at the mudline, and the effect of time-varying scour can be considered. This study assumes that the TMD operates in the fore–aft (FA) direction, while the vibration in the side–side (SS) direction is uncontrolled. Results show that scour can decrease the fatigue life by about 24.1 % and that the TMD can effectively suppress vibration and increase the fatigue life. When the scour depth reaches 1.3 times the pile diameter, the TMD with a mass ratio of 1 % can increase the fatigue life of an OWT's support structure by about 64.6 %. Further, it is found that the fatigue life can be extended by 25 % with the TMD optimized by the proposed optimization technique rather than using a traditional design method which does not take the change in dynamic characteristics into account.

Study on creep characteristics and reduction coefficient of geomembrane under top pressure

A new top-pressure creep test device was developed to simulate the stress conditions of geomembrane in a real working state. CBR puncture and top pressure creep tests under different load levels were conducted using this device to study the creep characteristics of the geomembrane at top pressure. The top pressure creep reduction coefficients under different load levels and design lives were calculated and compared with the regular tensile creep reduction coefficients. Quantitative relationships between the creep-reduction coefficient, design life, and failure strain were established to predict the top-pressure creep-reduction coefficient. The results indicated that the top pressure creep reduction coefficient was greater than that of regular tensile creep. The creep reduction coefficient changed minimally with an increase in the design life. The top pressure creep reduction coefficient remained stable with an increase in the top pressure area strain for different design lives. Based on the results, to improve the safety and durability of engineering structures, the top pressure creep reduction coefficient should be used in the design of geosynthetics affected by the top pressure.

Framework for determining the safety distance of karst caves adjacent to tunnels

Karst caves pose safety issues for tunnels in karst areas. Karst caves at a certain distance from the tunnel must be treated fully to mitigate risks. A threshold of 3 m is typically adopted; caves within this threshold are fully treated, while those beyond are left untreated, regardless of the geological environment, cave features, tunnel design, operating conditions, etc. This poses risks to tunnel safety during construction and operation. This paper proposes a novel framework based on the aforementioned aspects to determine the treatment distance for caves from the perspective of uncertainty and risk. Geological conditions include the soil and rock type, weathering degree, underground water system, and pH. Karst caves primarily include the size, shape, distance, spatial distribution, density, and filling condition; the tunnel aspect refers to the tunnel diameter, construction method, design life, importance, lining, and tolerable criterion; and operation conditions refer to the vehicle speed, operation time, vehicle load, and maintenance. Herein, the parameters/indices for these aspects and methods to quantify their values are described. A decision-making process is illustrated to revive the mindset of risks in tunnel engineering. The proposed framework is effective for optimizing decision-making in karst cave treatment for tunnels in karst areas.

Cyclic response of laterally loaded pile after storm loading

Offshore wind farms in China are in tropical cyclone zones, where typhoons or tropical revolving storms will pass through every year and can produce huge loads on the offshore wind turbines. Therefore, the stability of OWT foundations after storm loading is critical to ensure the safe operation and design life of turbines. While monopile is the most used foundation type for offshore wind, little studies exist on the cyclic response of monopile after storm loading. To fill the gap, this study presents a unique centrifuge and numerical study on the cyclic deflection response of monopile in medium dense sand after extreme storm loading. The centrifuge test was performed at 100g on a typical monopile with a prototype diameter (D) and embedded depth (L) of 4 m and 60 m, respectively. Finite element (FE) simulations using the advanced hypoplastic model for sand were performed to back-analyze the centrifuge test and provide further insights into the test results. From the centrifuge test, a unique “self-healing” beahviour of monopile was observed for the first time, where the foundation exhibited a deflection recovery response and tilted back to its initial position under the small amplitude cyclic load after the storm loading. This “self-healing” beahviour was also replicated by the FE model. By looking into the computed pile-soil interaction and soil element states around the pile, it was found that the “self-healing” response is attributed to the “lock-in” bending moment after the storm loading. This “lock-in” bending moment generated significant compressive horizontal stress on the soil elements behind the pile and produced more compressive strain under cyclic loading. As a result, the pile exhibited the “self-healing” response and tilted back against the loading direction.

Stochastic finite element-based reliability of corroded pipelines with interacting corrosion clusters

The performance of corroded carbon steel pipelines over the course of their design life is generally assessed by probabilistic variables with explicit limit state functions, rather than the realistic representation with stochastic spatial variability and implicit failure considerations. This could be due to the complexities associated with the uncertainty quantification and performance estimation approaches. The consideration of random process representation of corrosion defect propagation and material properties, along with computationally effective implicit formulation is expected to lead to accurate reliability outcomes. This paper proposes a stochastic-based reliability framework considering suitable failure modes represented with surrogate models, that lead to time-variant reliability estimation. The approach combines surrogate computational model with scalar random variables and random field discretisation of underlying characteristics to generate experimental designs and corresponding surrogate models over a time period, which are used to derive reliability estimates. The outcomes of this approach are compared with the results of explicit time-dependent functions. It was observed that reliability estimates of the corroded pipeline change rapidly after the fifth year, providing a much lesser probability of failure (of 3.08×10−3 at 30th-year) compared to the existing models (of 1.80×10−2 at 30th-year), thereby providing an effective pathway for risk-based maintenance and management.

Physical Modelling Of Rock Bags Under Wave Attack

In 1987, rock bags were developed by Kyowa in Japan to protect against erosion from hydraulic processes in riverine, lake, coastal and marine environments. Since 2020, rock bags have been used as a temporary or emergency coastal protection unit for seawalls on some beaches in Australia (e.g. Wamberal Beach and Collaroy Beach). These structures have typically been built against a pre-existing dune or eroded dune scarp for protection of landward coastal assets. While a limited amount of hydraulic scale modelling has been undertaken for some rock bag applications, their behaviour in shallow water, coastal environments under wave forces had not previously been quantitively evaluated. A two‑stage physical modelling program was carried out to assess the behaviour of rock bags when used in this emerging erosion protection application. As a result of the scale laboratory tests for shallow water seawalls constructed from rock bags, specific results were obtained for a proposed structure at Stockton Beach (Newcastle, Australia) as well as producing generic design information that could be applied at other locations. As expected, the design wave height for rock bag damage (displacement) was found to be inversely proportional to wave period. Preliminary design stability curves were developed for rock bags under monochromatic and irregular wave attack. In addition to displacement, settlement of the rock bags was observed during the modelling, and it is recommended that consideration should be given to vertical settlement over the design life of these structures. Wave runup was also found to be high; this is also an important consideration for future rock bag seawalls in either establishing the design crest level to prevent wave overtopping or adopting and managing a permissible amount of wave overtopping during a design event.

Analysis of Deterioration Characteristics of Service-Aged XLPE Cables According to Installation Location of Combined Heat and Power Plant

The number of XLPE cables being used near or beyond their design life is increasing. The importance of timely cable replacement is necessary. Therefore, research is actively being conducted using VLF Tan δ diagnostic technology to assess the insulation condition of cables. Present studies lack in measuring and analyzing the VLF Tan δ of service-aged XLPE cables. Additionally, there is a research gap considering the operating environment. Therefore, it is needed to diagnose and analyze the insulation condition of the same service-aged cable when it is operated in a different environment. This paper assesses and analyzes the insulation condition of cables installed in the BFP, cooling tower, and deaerator booster pump of a combined heat and power plant. Each cable was evaluated by measuring the VLF Tan δ, the dielectric breakdown test of the cable, and the tensile strength, elongation at break, crystallinity, and dielectric strength of the XLPE specimens. Additionally, the correlation between the VLF Tan δ and other characteristics was also analyzed. It was found that degradation progressed in the order of the BFP, the cooling tower, and the deaerator booster pump. Therefore, it was confirmed that even for the same cable, deterioration varies depending on the installation location.

Test blanket modules piping systems calculation method according to RCC-MRx code

The ITER Test Blanket Modules (TBMs) are installed and operated inside the vacuum vessel (VV) at equatorial ports located within port plugs (PP). The Pipe Forest (PF) is a network of pipes connecting the Ancillary Equipment Unit (AEU) to the TBMs. Depending of the TBM, the Pipe Forest includes various piping system such as Water Coolant (350°, 188 bars), Helium Coolant (500°, 100 bars) Lithium Lead and Tritium Extraction System. During operating states, the Pipe Forest main function is to withstand loads in normal, incidental and accidental situations according to RCC-MRx code criteria (including design rules for mechanical components for fusion installations). It includes severe thermomechanical loadings due to the thermal expansion added to seismic and vertical displacements events. In addition, the PF layout must satisfy constructability in constraint environments and maximize the space available for man access, which constitutes a real challenge for design.Since no existing RCC-MRx post-processing tool exists off the shelves, a specific methodology for pipe stress analysis is being developed by ITER, CEA and ASSYSTEM. This methodology starts with a post-processing calculation tool of stresses and reaction forces for looping back into the structural calculation. Moreover, a specific extraction module from 3D model to processing tool allows the conversion of CAD data to calculation entry files. Finally, a feedback loop is also re-integrated into the core CAD model through an import module, enabling the tracking of displacements and evaluate the impact of incorporating pipe movements into the analysis.This paper describes the pipe stress analysis methodology and its application for Pipe Forest system design life cycle. It covers the historical evolution of the routing including introduction of expansion loops. More recently, it incorporates the integrated calculation of the entire port cell, spanning from the back of the TBM sets, up to the connection pipes of the vertical shaft.

Theoretical and simulation of central elliptical hole with rectangular plate

A study on design engineering components with slot, notches is very important, because there is a stress increases/failure region area, where the force/stress is concentrating more and more. The elastic stress concentration mainly depends on the mode of loading, materials, and geometry of the design engineering components. The design engineers, academicians, and researchers concentrated and focused on fail-safe design and safe life design. A Plate is considered with different slots, such as circular and elliptical. The main objective of this study is to find out the stress concentration factor in plates with various cutout shapes. This concept is used in design components/structures, for finding the elastic stress concentration. The methods compared are tabulated with their findings. Singularities of the circular hole and elliptical hole in rectangular plates are considered in the present study. The finite Element Method (FEM) was used for fine mesh and ANSYS WORKBENCH software was used for extracting the results and results were validated by analytical or experimental methods.

Cyclic shear testing of artificially corroded reinforced concrete short circular piers

Chloride-induced deterioration of reinforced concrete (RC) structures is an increasingly vital topic among asset management and structural maintenance fields, as many RC bridges and other structures are reaching the end of their initial design lives. Deterioration of the transverse reinforcement in RC piers leads to the direct loss of shear and confinement-related mechanical properties as degradation advances with time. This research investigates the seismic response of fourteen short RC circular piers subjected to artificial chloride-induced corrosion. Each pier is designed to trigger a shear-dominated failure and artificially corroded at two current densities. A maximum average mass loss of 10.5% and 43.0% was measured in the longitudinal and spiral reinforcement, respectively. The influence of confinement effectiveness, spiral diameter, and aspect ratio on the rate of shear capacity degradation are included as test parameters in this study. Results indicate that shear deformation begins to govern performance at moderate to severe deterioration, which precedes the onset of brittle shear-dominated failure modes. Ultimate deflection is more adversely affected by increasing corrosion than all other measured properties, with a maximum observed reduction of 70.9% compared to a maximum 37.5% reduction observed in peak shear capacity. Several existing theoretical models are introduced and evaluated on their ability to predict the shear capacity of the experimental tests. Based on the results, those models directly evaluating the circular section without needing an equivalent section transformation offer the most accurate and reliable predictions.

Analysis of Offshore Wind Turbine by Considering Soil-Pile-Structure Interaction: Effect of Sea-Wave Load Duration

ABSTRACT Offshore Wind Turbines (OWTs) confront different types of environmental loads during their lifetime. One of the most significant loads is the cyclic sea-wave load which affects the OWT system during the approximate 25 years of design life. This lateral cyclic load can influence the response of the OWT system because of accumulated permanent displacement and excess pore water pressure generation in soil. This procedure can change pile-soil stiffness. However, the behavior of OWT and its foundations is mostly studied under short-term cyclic loading, and the effects of duration of the cyclic loads on pile-soil interaction and performance of the foundation are not well understood and documented. Therefore, there is a lack of guidance in codes for the duration effects of cyclic loads on the structural and geotechnical response of OWTs. In this regard, the current study considers the effects of duration of the cyclic loads on serviceability and performance of the OWT system by considering soil-foundation-structure interaction using a 2-D finite element method. The behavior of the OWT system is evaluated based on the internal forces and deformation of the monopile foundation, shear strain, and excess pore water pressure ratio in the surrounding soil. Besides, liquefaction susceptibility in the sandy soil layer at the vicinity of the monopile and its effect on the performance of the foundation is investigated. Finally, the results can provide guidance on estimation of the dynamic performance of the OWT system during long-term cyclic loads. They can be used to specify the need for consideration of the duration of cyclic lateral loads for the design of OWT structures.

Fatigue Behavior and Fracture Surface Analysis of Corroded High-Strength Bridge Cable Wires.

Bridge cable wires suffer from alternating stress and environmental erosion, leading to premature failure prior to its design life. This paper investigates the fatigue and mechanical behaviors of corroded bridge cable wires with a zinc-aluminum (Zn-Al) alloy coating. Based on the salt spray corrosion test and microstructure analysis, the anti-corrosion resistance and corrosion appearance characteristics of the Zn-Al alloy coating and galvanized coating were investigated. The Zn-Al alloy coating was superior in resistance to corrosion fatigue for the improvement in toughness and the generation of anti-corrosion Zn-Al and Fe-Zn-Al phases. Equations of the accelerated corrosion depth of the steel wires had been regressed to roughly estimate the corrosion life of the Zn-Al alloy coating, which can reach 29.1 years with a thickness of 70 μm. The fatigue and mechanical properties of the bare wires after the salt spray test were further studied based on tensile tests and fatigue tests. The fatigue properties of the bridge cable wire would decrease with the corrosion degree due to the deterioration and embrittlement of materials, where ductility characterized by the elongation rate was the most affected. Fracture surfaces of the wires were captured and analyzed based on a method for recognizing graphical contours. Insufficient fatigue life may occur in the steel wires after corrosion and increase with the degree of corrosion. The pit depth logarithmically weakened the fatigue life of steel wires for the weakening of fatigue toughness and the bearing area. The flat fracture was more common with a single fatigue source, while multiple fatigue sources led to step-like fractures for the generation of multiple dispersed crack propagation regions. Corrosion fatigue was more sensitive to the existence of fatigue sources than the reduction. Multiple initiation sources significantly reduced the fatigue life due to the cracking facilitation of the joint effect of multiple pits. The electrochemical reactions of corrosion can lead to material embrittlement and a reducing effect on the fracture toughness of the steel wires.

Investigating the Impact of Domestic Sewage on Asphalt Concrete Pavement Strength

This study evaluates the impact of exposing asphalt pavement to sewage and fresh water. In total, 87 samples were prepared, where half of them were immersed in sewage and the others were immersed in freshwater. The Marshall mix design method was adopted for the preparation of samples. Three immersed samples were tested for stability and flow every 24 hours in both fresh water and sewage, comparing the results with a control sample. The samples immersed in fresh water lost their stability and flow after 11 days, while the ones immersed in sewage water lost their stability and flow after 9 days. Furthermore, the loss in stability for samples immersed in fresh water and sewage after 14 days was found to be 38.8 and 55.6%, respectively. The results revealed that sewage water affects asphalt concrete pavement more severely than freshwater. Finally, it was concluded that proper drainage and adequate supplemental sewerage systems are necessary to maintain the desired strength of the pavement throughout its design life.

Research on chloride ion permeability resistance of concretes bonded with CFRP sheets under dry-wet cycles

Considering the widespread application of carbon fibre-reinforced polymer (CFRP) as a protective material for reinforced concrete (RC) structures, this study focuses on the ability of CFRP laminates with different numbers of layers bonded to the concrete surface to reduce the ingress of chloride ions. Variations in the free chloride concentration distribution in concrete before and after CFRP bonding were explored systematically. Nonlinear fitting was applied to the experimental data to establish a calculation model for the diffusion of free chloride ions in concrete with CFRP bonded to the surface, which was subsequently validated. Based on the proposed model, the reduction in the surface chloride concentration of concrete after bonding different numbers of CFRP layers was quantified as the reduction value. Moreover, recommendations for the durable design of RC structures bonded with CFRP in wet-dry cyclic environments are provided. The results indicate that the surface chloride concentration in concrete increases continuously with increasing wet-dry cycles, eventually reaching a steady state. Compared with the concrete specimens without CFRP bonding, the bonding of one, two, or three layers of CFRP led to reductions in the stable surface chloride concentration of concrete by 70.8%, 82.6%, and 84.9%, respectively. And no obvious convection zone was observed in the concrete after CFRP bonding. The validation results of the proposed calculation model demonstrated its high accuracy, making it suitable for durable design and service life prediction.

Fatigue damage analysis method of offshore wind turbine foundation

The systems of offshore wind turbines are established in a complex marine environment, and are subjected to all kinds of ocean loadings such as waves, currents and wind for a long time. It is found that offshore wind turbine foundations are seldom damaged due to the problem of strength and stability under normal operation conditions. Most of the damages are caused by the fatigue damage under long-term loads. Aimed to this problem, the monopile foundation of offshore wind turbine is analyzed as an example in this study. The fatigue damage is analyzed systematically using the method of time-domain, combining the rain-flow counting method, S–N curve with linear and nonlinear fatigue damage models. In addition, a modified nonlinear fatigue damage model is proposed based on the Corten-Dolan and Manson-Halford nonlinear fatigue damage models, which can consider the modification of load interactions and the effect of loading sequence. In this way, the short-term fatigue damage value of offshore wind turbine foundation can be obtained. On the basis, the long-term probability distribution function of wind speed is obtained according to the actual monitoring results of wind load, and the fatigue damage value of the offshore wind turbine foundation in the design life can be obtained. Finally, a complete fatigue damage analysis method of offshore wind turbines is proposed, which is applicable to both short-term fatigue damage and long-term fatigue damage.

EXPERIMENTAL RESEARCH CONCERNING WATERSIDE CORROSION OF FUEL CLADDING IN CANDU REACTOR

EXPERIMENTAL RESEARCH CONCERNING WATERSIDE CORROSION OF FUEL CLADDING IN CANDU REACTOR

Planning for wastewater infrastructure adaptation under deep uncertainty

Infrastructure in low-lying coastal areas faces challenges from climate change, sea level rise, and the impact of compound hazards. Dynamic adaptive pathways planning (DAPP) is increasingly being applied as a way of planning under deep uncertainty. Stress testing for robustness is an integral part of DAPP which provides decision-makers with confidence. We outline a seven-step approach—combining scoping workshops, systems mapping, DAPP, exploratory modelling, robust decision-making, real options analysis and validation workshops—to support decision-making for infrastructure in low-lying coastal areas. We apply the seven steps to two wastewater treatment plant (WWTP) case studies in New Zealand to quantify indicators, signals, triggers and adaptation thresholds within DAPP plans and to identify adaptation pathways that are robust against future uncertainty. Case study one focuses on the implementation of an existing DAPP at Helensville WWTP. Our modelling enabled the challenge of quantifying indicators for adaptation thresholds and triggers to be overcome. We show that an adaptation threshold occurs at 31 cm of RSLR, the trigger point is sufficient lead time to enable relocation, and the indicator is the rate of observed RSLR. Case study one demonstrates in a quantitative way how an existing DAPP can be functionally implemented by a water management agency. Modelling for case study two, the Seaview WWTP, showed that 26 cm and 56 cm of RSLR are key thresholds. Nuisance flooding may occur after 26 cm of RSLR, which could happen as early as 2040 under a high emissions scenario. Inundation of plant assets may occur after 56 cm of RSLR, which could occur as early as 2060. Modelling showed that implementing changes to plant layout would allow the plant to remain on site for its design life (until 2080). Five adaptation archetypes were developed—sequences of adaptive actions that achieve the performance objective of continuing levels of service and avoid inundation of WWTPs. The seven-step approach is a way to stress-test a DAPP, to quantify signals, triggers and adaptation thresholds and to simulate implementation of a DAPP under a range of scenarios. This can facilitate more robust decision-making for wastewater infrastructure assets under future uncertainty.

Influence of thermomechanical treatment on mechanical properties of CLAM steel

To enhance the creep resistance of CLAM steel and thus elevate its maximum service temperature, in our prior research, a superior thermomechanical treatment process was developed based on thermal simulation experiments conducted. This study employed forging to achieve the desired thermal deformation in accordance with the superior thermomechanical treatment process, followed by mechanical property testing post tempering. Comparative analysis with normalized and tempered CLAM steel (N + T CLAM steel) revealed notable improvements in yield strengths ranging from 31–55 %, ultimate tensile strengths from 30–46 %, and a reduction in total elongations by 12–21 % at both room temperature and elevated temperatures. Additionally, the ductile-to-brittle transition temperature (DBTT) increased from -65 °C to -27 °C. Creep behavior of N + T CLAM steel exhibited similarities to other RAFM steels, with stress exponents measured at 500 °C, 550 °C, 600 °C, and 650 °C recorded as 16.5, 15.0, 10.2, and 7.8, respectively. The creep activation energy was determined to be 556 kJ/mol, closely aligning with results from Eurofer 97 steel and F82H steel, and approximately twice the self-diffusion activation energy of iron. The Larson-Miller parameter method was employed to forecast stress-rupture limits under various conditions, with a predicted result of 120 MPa under typical design life conditions (550 °C / 100,000 h) for the cladding module, comparable to Eurofer 97 steel and F82H steel. TMT CLAM steel exhibited a stress exponent of 16.7 at 550 °C, with a creep activation energy of 578 kJ/mol. Under typical design life conditions (550 °C / 100,000 h) for the cladding module, the predicted stress-rupture limit increased to 176 MPa, representing a 47 % improvement over N+T CLAM steel. Moreover, under the same conditions (550 °C / 230 MPa), the rupture time of TMT CLAM steel was 54 times longer than that of N+T CLAM steel.

Estimating the useful life of the sempor reservoir using erosion modelling

Sedimentation determines how optimal a reservoir functions throughout its design life. The Sempor Reservoir in Central Java, Indonesia, will be 45 years old in 2023. At least 15 million m3 of particles have been sedimented in the reservoir for >30 years, reducing its function as an irrigation water source to only 60%. Therefore, assessing its performance in providing irrigation water and generating hydropower electricity is essential, given that its design life ends in 2028. This study was conducted to analyse the sedimentation and estimate the useful life of the Sempor Reservoir based on the erosion potential in its catchment area. The potential sedimentation rate was formulated from erosion potential assessed using the universal soil loss equation (USLE) model, sediment delivery ratio (SDR) and trap efficiency (TE). By contrast, the actual sedimentation rate was determined from changes in the dead storage capacity from 2013 to 2023. The interpolation performance evaluation of the bathymetric survey results was tested using the coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), and mean absolute percentage error (MAPE) which resulted in values of 0.917; 0.87; and 13.03%, respectively. The results show that the catchment area had an erosion potential of 3,405,353.86 t∙a−1, resulting in a potential sedimentation rate of 309,106.63 m3∙a−1. The calculated actual sedimentation rate was 33,903.28 m3∙a−1. Therefore, the useful life of the Sempor Reservoir was estimated to end in 0.5 years and 4.59 years based on the potential and actual sedimentation rates, respectively.

The role of additives in estimating service life of self-compacting concrete mix design using FIB modelling

The purpose of this study is to examine the influence of additives on estimating the useful service life of self-compacting concrete (SCC). For that, durability tests were performed on 43 SCC mix designs to estimating the service life of SCC based on the FIB model. The investigated supplementary materials included xanthan gum at concentrations of 0.2% and 0.25% by weight of cement, microsilica at concentrations of 5%, 7% and 10% by weight of cement, and nanosilica at concentrations of 2%, 3% and 4% by weight of cement. All 43 designs met the reliability index of the model, thereby obtaining the estimated service life for each design. The findings revealed that in chloride-rich environments, the control sample exhibited greater penetration depth compared to the concretes incorporating xanthan gum, microsilica and nanosilica additives. This observation suggests that the inclusion of xanthan gum extends the service life of SCC due to the formation of a denser and more cohesive structure in the hydration products of xanthan gum-modified concrete. Additionally, the investigations conducted indicate that the presence of nano and micro additives effectively reduces voids, while xanthan gum plays a significant role in minimising cracking and enhancing the thickening properties of the concrete.