Fires are considered one of the main risks leading to building collapse. Lightweight concrete comprises a variety of components, each of which has a distinct behavior under the effect of temperature change. A total of sixteen concrete mixtures were investigated in this paper. A reference mix of concrete comprising simply ordinary Portland cement and ten mixes having varying percentages of fine and coarse lightweight aggregates (pumice), which were replaced gravel and sand by fine pumice and coarse aggregates pumice by 20%, 40%, 60%, 80%, and 100%, respectively. In addition, the study focused on the effects of adding fibers to lightweight aggregate concrete mixtures. Polypropylene fibers, carbon fibers, and steel fibers were employed as fiber additions. The binary mixture had higher density than the remaining mixtures containing one substitute. The behavior of six concrete mixes in addition to the reference mix of ordinary concrete after exposure to temperatures 100, 250, 350 and 450 °C for two hours and then cooled in two ways (water and air) as well as examined directly and the results showed that the concrete mixes containing fiber better behavior compared to other mixtures, especially at high temperature. If left to cool in the air, the lightweight concrete containing Volcanic Pumice can recover its compression strength after being exposed to high temperatures.

Regarding the significance of binder quantity, alkali activator molarities, and thermal curing, this work was utilized to geopolymerize with a potassium-based alkaline activator to strengthen soils. Five different molarities of palm oil fuel ash (POFA) in four different amounts were utilized to activate the clayey soil. POFA admixtures have been used to test soils. The results showed that for mixtures with 10 and 12.5 molarities, the unconfined compressive strength (UCS) with 15 % and 20 % of POFA was stronger. Comparing the strengths of the blends with various POFA amounts and concentration molarities allowed for this determination. To increase the strength, it is crucial to consider how the geopolymerization method's temperature and curing time affect the UCS of the soil-POFA mixture with and without fibers. The UCS of the treated soil mixtures was changed by heating at 30, 50, 70, and 90 degrees C. The outcomes demonstrate that increasing the curing temperature will hasten the alkaline activation process. After seven days of heating, the treated soil specimens with and without fibers exhibit the best mechanical properties at a healing temperature of about 70 degrees C, with compressive strengths of 16.7 and 11.4 MPa. The interaction between the geo-polymeric matrix and the fiber surface, the molarities of the alkaline solution, and the heating temperature were the most important aspects, according to an investigation of the microstructures, in improving the behavior of the reinforced mixes. By offering an efficient approach for increasing the qualities of soil treated by the alkali activation of POFA through the inclusion of glass fibers with adequate molarities of reagent and cure heating temperature, the current work offers new insights into soil stabilization operations. This has advantages over conventional calcium-based binders due to their emission of carbon dioxide during manufacture, which is one of the major causes of global warming.

It has been established that using recycled materials to replace some of the fine aggregates is a viable solution. Most researchers focused on the durability aspect of wood sawdust concrete, while less information is available on its structural performance. Therefore, this article aimed to investigate the performance of reinforced concrete beams fabricated from concrete with a partially replaced fine aggregate (FA) by wood sawdust (WS) in the range of 5–45 % (by weight). Six beams underwent 4-point bending tests till collapse. The beams' slump, density, compressive strength, cracking and failure mode, energy absorption, and economic and environmental aspects were studied. The findings showed that the failure region of sawdust concrete was more significant than the reference samples. Despite the compressive strength of the concrete containing different ratios of sawdust being reduced by about 7–30 %, the target compressive strength still has a limit of low to normal concrete grade. The results show that the increase in sawdust percentages decreased the acquired absorbed energy of the subjected load to reach failure. A cost reduction of 9 % and a cost index of 61 % is achieved using wooden sawdust-based concrete. By substituting sawdust for fine aggregate, the sustainability of sawdust concrete in terms of cost and environmental advantages may be improved. In addition, it is well-known that harnessing the transformative potential of industrial waste in concrete production not only minimizes landfill usage, but also promotes resource efficiency, reduces carbon emissions, and advances the circular economy, propelling designers, engineering and builders towards a greener and more sustainable future in the construction industry. According to the test findings, wood sawdust may be utilized to produce normal and low-strength structural concrete.

The construction industry, increasingly prioritizing sustainability, necessitates an exploration of technology and management's role in mitigating material waste at construction sites. This study examines the impact of 3R, IBS, BIM, and MMA in enhancing Construction Site Performance (CSP) in the Malaysian construction sector. Seven hypotheses were formulated to assess the relationship between technology adoption, material management practices, and the moderating influence of Material Management Adoption (MMA) on CSP. Data were collected through an online survey from 295 valid responses in the Malaysian construction sector, focusing on professionals involved in solid waste management. Utilizing Partial Least Squares - Structural Equation Modeling (PLS-SEM) and Statistical Package for the Social Sciences (SPSS), the findings highlight the importance of technological integration, efficient material management, and competitive strategies in effective material waste mitigation. Furthermore, the qualitative aspect of the study, conducted among 6 solid waste organizations in Malaysia, enriches the findings by providing nuanced insights into local practices and challenges. Emphasizing the importance of contextual insights, the study addresses professionals involved in solid waste management within the Malaysian construction industry. The geographical specificity adds depth to the analysis, offering a comprehensive understanding of regional dynamics. Despite acknowledging limitations in technology and material usage, the study offers recommendations for refining waste mitigation and improving construction site performance. This research model offers actionable insights for construction site stakeholders, emphasizing the criticality of waste mitigation and CSP. The results, both quantitative and qualitative, underscore the potential of these practices within the Malaysian construction industry to foster innovation and drive positive change.

The present research employs new boosting-based ensemble machine learning models i.e., gradient boosting (GB) and adaptive boosting (AdaBoost) to predict the unconfined compressive strength (UCS) of geopolymer stabilized clayey soil. The GB and AdaBoost models were developed and validated using 270 clayey soil samples stabilized with geopolymer, with ground-granulated blast-furnace slag and fly ash as source materials and sodium hydroxide solution as alkali activator. The database was randomly divided into training (80%) and testing (20%) sets for model development and validation. Several performance metrics, including coefficient of determination (R2), mean absolute error (MAE), root mean square error (RMSE), and mean squared error (MSE), were utilized to assess the accuracy and reliability of the developed models. The statistical results of this research showed that the GB and AdaBoost are reliable models based on the obtained values of R2 (= 0.980, 0.975), MAE (= 0.585, 0.655), RMSE (= 0.969, 1.088), and MSE (= 0.940, 1.185) for the testing dataset, respectively compared to the widely used artificial neural network, random forest, extreme gradient boosting, multivariable regression, and multi-gen genetic programming based models. Furthermore, the sensitivity analysis result shows that ground-granulated blast-furnace slag content was the key parameter affecting the UCS.

Many researchers are interested in using natural fibres to treat due to recent advancements in polymer characteristics. The mechanical properties of three types of bars are studied in this paper: Cotton Fibre-Reinforced Polymer bars, Cotton/Carbon Fibre-Reinforced Polymer bars, and Cotton/Glass Fibre-Reinforced Polymer bars. The goal of the paper was to create low-cost bars with comparable mechanical performance and corrosion resistance to steel reinforcement. The bars were made using two methods: fibres immersed in polymer and fibres coated with polymer by repeated tension and relaxation of fibres. The second method produced better results in terms of the tensile strength of Cot.CFRP, Cot.GFRP, and Cot.FRP bars, which were 688, 477, and 284 MPa, respectively, and the stress–strain curve revealed brittle behaviour for all bars and modulus of elasticity of 43, 31 and 22 GPa. When sand was put on the bar’s surface, the bars demonstrated a good connection with the concrete. It also showed good resistance to moisture, alkaline solutions and acids, as well as heat resistance at temperatures below 200°C.

Automation technology in the construction industry is the use of advanced tools, devices, and processes that reduce manual labor and enhance efficiency in various construction activities. Automation technology can minimize waste, optimize resource utilization, and reduce the environmental impact of construction processes. This study aims to examine the relationship between automation technology adoptions (ATAs) utilizing reduce, reuse, and recycle (3R), building information modeling (BIM), industrialized building systems (IBSs), green building index (GBI), and Internet of Things (IoT) practices toward construction site performance (CSP) to measure their influences on material waste mitigation measures at Johor construction sites. To achieve these goals, five hypotheses were developed to explore the association between ATA and CSP. Data were gathered utilizing an online survey. The participants were contractors and expert practitioners in the Johor construction industry, including architects, project managers, and academicians/researchers. A total of 257 valid responses were used to investigate the assumptions. The partial least squares structural equation modeling (PLS-SEM) procedure was used. The findings revealed that ATA utilizing 3R, BIM, IBS, GBI, and IoT as material mitigation measures positively enhances CSP.

The construction business has always been at the forefront of technological advancements, and this trend has only accelerated in recent years as one of the important contexts among the other numerous new technologies. The current study aims to examine the relationship between Automation Technology Adoptions (ATA) and Construction Site Performance (CSP) and their influence on material waste mitigation measures in Johor construction sites. Data was gathered utilizing an online survey method, with the participants from the Johor construction industries representing contractors and experts. A total of 257 responses were valid to investigate the assumptions of the validations, and ‘Partial Lease Square - Structural Equation Modeling’ (PLS-SEM) procedure has been used. The adopted model may be used to help construction site managers and workers understand the importance of the ATA, CSP, and their utilization as material waste management approaches. The obtained results emphasize the relevance of automation technology adoption for mitigating construction material waste in construction sites with such a clear significance and clarity under the use of automation in construction sites. These findings will assist construction professionals to manage their materials on the job site and complete their projects.

In this study, different coating systems, including solvent-based epoxy and water-based acrylic resins, were evaluated for their potential as an alternative to chromate coatings in order to avoid Cr(VI) toxic hazards. The resins were used as either pigment-free coatings or were formulated with 20-wt% zinc/aluminum pigments. The coatings were subsequently applied on galvanized ST12 steel plates and their corrosion resistance was investigated by electrochemical impedance spectroscopy (EIS) evaluations. The effect of the binder and pigment type on the impact resistance of two different polymeric coatings was also evaluated. The results of impact tests revealed completely peeled film from the substrate for epoxy coatings. However, under the same experimental conditions, very few small cracks were created in water-based acrylic coatings for both pigmented and pigment-free cases. In addition, some other parameters such as drying time and coating cost were taken into account to select a good alternative to chromate coatings. The results of this work can facilitate the introduction of an inexpensive environmentally friendly acrylic coating as a promising self-healing alternative to chromate coating.

In this technology era, sustainable construction practices have become quite imperative. The exploration of alternative materials to reduce the environmental footprint is of paramount importance. This research paper delves into an exhaustive investigation concerning the utilization of recycled coarse aggregates (RCA) and rubber particles (RP) in concrete. It contributes to the growing body of knowledge aimed at fostering sustainable development in the construction industry by reducing waste, promoting recycling, and mitigating the environmental footprint of building materials. The objective of the study is to evaluate the potential benefits and limitations associated with incorporating these materials, thereby providing a sustainable alternative to conventional concrete. In this research, construction and demolition waste were recycled and used as RCA as a fractional switch of natural coarse aggregate (NCA) from 0% to 100%, with an increment of 20% replacement of NCA in concrete. The RP received from discarded tires generated as automobile industry waste were used as a volumetric fractional substitution of sand in concrete from 0% to 20%, with a 5% increment. No pre-treatment for RCA and RP was carried out before their utilization in concrete. A total of 26 mixes, including control concrete without NCA and RP, with a design strength of 40 MPa, were prepared and tested. Concrete mixes were examined for workability, density, mechanical, and durability properties. It was found that the concrete with 60% RCA and 10% RP showed satisfactory results in evaluation with the strength parameters of control concrete, as the compressive strength obtained for this concrete mix is 40.18 MPa, similar to the control mix. The optimization for RCA and RP was conducted using Response Surface Methodology (RSM). The major concern observed was a rise in water absorption with an increase in the percentage replacement of NCA and natural sand by RCA and RP. Findings from the investigation illustrate a promising prospect for the use of RCA and RP in concrete applications, displaying competent mechanical properties and enhanced durability under certain conditions, offering a viable option for environmentally friendly construction practices. However, the research also sheds light on some constraints and challenges, such as the variability in the quality of RCA and the necessity for meticulous quality control to ensure the reliability and consistency of the end product. It is discerned that further refinement in processing techniques and quality assurance measures is pivotal for mainstream adoption of RCA and RP in concrete construction.

A prestressed concrete bridge was built in 1963 with BBRV cables. It has three spans and a total length of 134.8 m. Due to mining activities the bridge was loaded with trucks with a total weight of 90 ton during 2012-2014 and from 2019. Crack development has been monitored manually and from 2020 with strain gauges and LVDTs.

Cracks normally vary between 0.1 to 0.3 mm in width and grow in length with time. In November 2020 some of the strain gauges on the concrete showed alarming growth and the bridge was closed for traffic. Additional strain gauges were installed on vertical reinforcement bars and an assessment was carried out of the fatigue capacity of the bridge. It was found that the new strain gauges did not indicate any growth in strain and that the fatigue capacity was sufficient. The bridge could be opened again for traffic after being closed for five weeks. Monitoring drift in the strain gauges and fatigue are discussed.

The backbone of European infrastructure was built after the end of the second World War and has reached, or is near to, the end of its nominal design life. This issue urges the development of structural assessment procedures that can provide infrastructure managers the information to make decisions for repairing, upgrading, or replacement. In this paper, a methodology based on load testing and Structural Health Monitoring (SHM) for the assessment of a 65- year-old prestressed concrete bridge located in Northern Sweden is presented. The retrieved data is used to develop and calibrate structural models with different levels of data completeness. The SHM procedure includes the evaluation of material properties by diagnostics, definition of the layout and installation of the instrumentation, test execution, and data analysis. A preliminary structural model is developed based only on the original design parameters, and it is sequentially updated with monitoring data retrieved during a performed proof loading test of the bridge.

The reduction of the structural capacity and eventual collapse of existing concrete bridges is often related to the loss of the initial prestressing forces. This loss can be associated to immediate or time dependent factors such as elastic shortening, creep, relaxation, loading, and cracking, among others. In addition, environmental factors can lead to corrosion of the strands with the subsequent reduction of their area, loss of bond with the concrete and additional cracking which in turn will influence the value of the residual prestress force and the bridge capacity. Therefore, the evaluation of such losses is critical in the decision-making process of defining a financial and environmental cost optimized intervention strategies (e.g., strengthening or replacement). In this paper, a detailed literature review regarding destructive and non-destructive methods for measuring the residual force in prestressed concrete bridges is carried out and used to develop a database of existing experimental tests.

Over the last decades, economic growth and sustained development have enforced the need to ensure reliable and long-lasting infrastructure network to guarantee serviceability and safety. Nevertheless, detrimental effects can lead over time to insufficient structural performance under increasing service loadings and extreme events. Hence, Structural Health Monitoring (SHM) arises as a solution to cope with the need of having timely and continuous data to assess the state of crucial structural assets, such as prestressed concrete bridges. On this matter, the validation of the retrieved data becomes essential for the risk-based decision making in the assessment of bridges, where selecting the most suitable monitoring system could allow to addressed main causes to the right phenomena of deterioration during the service life of the bridge. Consistently with these efforts, this paper deals with a comparative study between the data acquired by different strain-based sensors such as Fiber optic systems (FOS) and strain gauges that were installed to monitor a proof loading test developed on a 65-year-old balanced cantilever prestressed concrete bridge located in Northern Sweden. The monitored data led to establish main differences between emerging types of monitoring systems such as FOS to the well-based strain gauges when exposed to low temperature conditions. Conclusions regarding the influencing parameters between both retrieved data are drawn when evaluating the structural response under serviceability loading conditions is performed, supporting decision makers when different levels of structural assessment are required.

The transport infrastructure consists of roads, bridges, and tunnel networks. Among these, bridges, viaducts, and tunnels are particularly vulnerable due to structural degrad-ation caused by environmental conditions, overloading, and other factors. Ensuring the safety of these assets, especially at the network level, is a significant challenge. The emergence of Bridge Management Systems (BMS) addresses the need for comprehensive information in managing inspections, condition assessments, and optimizing investments in bridge maintenance. Despite the benefits, many countries face challenges in identifying high-risk bridges. Issues include the lack of high-quality data, mixed ownership of assets, diverse management system platforms, varying condition rating schemes, and the absence of a risk-based assessment. This review aims to highlight current practices and research efforts in evaluating bridge condition indices/ratings (BCI) for existing bridges. The identified knowledge gaps emphasize the need for national authorities to develop policies leading to a unified and functional approach for condition rating.

The direct socio-economic consequences of the deterioration of aging infrastructure systems have triggered a continuous process of revising and updating current design standards and guidelines for critical network components. Specifically, long-term degradation processes demand the analysis and evaluation of vital structural assets such as prestressed concrete bridges. It is crucial to develop theoretically consistent, user-friendly, and non-destructive methodologies that engineering professionals can employ to prevent and mitigate potential catastrophic outcomes during the service life of these bridges. This study provides a thorough review of the available testing methods employed over the years for prestressed concrete bridges and introduces a comprehensive framework for evaluating existing methods for residual prestress force assessment. Through a multi-criteria selection process, the three most feasible tests were designed and carried out on an existing 66-year-old balanced cantilever box girder bridge exposed to freezing temperatures that affected the instrumentation plan and test execution. Finally, predictive models compliant with standard codes were calibrated based on the experimental results and the life cycle loss of prestress forces was evaluated to assess relevant bounding intervals. Findings reveal limited on-site testing and discrepancies between calculated residual forces and predictions by standard codes. The saw cut method showed a 18% difference from the initial applied prestress according to the prestress protocol, suggesting the use of a cover meter and concrete modulus evaluation for improved accuracy. The strand cutting method resulted in a 14% difference, emphasizing the need for stress redistribution assessment. The second-order deflection method showed a 6% difference, indicating a focus on enhanced boundary conditions and thorough sensitivity analysis for future investigations.

The present study is aimed at investigating the effect of hybridisation on Kevlar/E-Glass based epoxy composite laminate structures. Composites with 4 mm thickness and 16 layers of fibre (14 layers of E-glass centred and 2 outer layers of Kevlar) were fabricated using compression moulding technique. The fibre orientation of the Kevlar layers had 3 variations (0, 45 and 60°), whereas the E-glass fibre layers were maintained at 0° orientation. Tensile, flexural, impact (Charpy and Izod), interlaminar shear strength and ballistic impact tests were conducted. The ballistic test was performed using a gas gun with spherical hard body projectiles at the projectile velocity of 170 m/s. The pre-and post-impact velocities of the projectiles were measured using a high-speed camera. The energy absorbed by the composite laminates was further reported during the ballistic test, and a computerised tomographic scan was used to analyse the impact damage. The composites with 45° fibre orientation of Kevlar fibres showed better tensile strength, flexural strength, Charpy impact strength, and energy absorption. The energy absorbed by the composites with 45° fibre orientation was 58.68 J, which was 14% and 22% higher than the 0° and 60° oriented composites. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

As emission regulations in the EU are becoming stricter, the reduction of greenhouse gas emissions from the construction industry has become a pressing need. As part of the efforts related to this issue, it has been found that Environmental Life Cycle Analysis (LCA) approaches are required to optimize the design, construction, operation, and maintenance of buildings and infrastructure assets. In this paper, The Institution of Structural Engineers guidance on how to calculate the embodied carbon in structures is used as LCA model and evaluated in a case study. The guidance divides the structure´s life cycle into five stages (A1-A3: Product, A4-A5: Construction process, B1-B7: Use, C1-C4: End of live and D: Benefits and loads beyond the system boundary) and the environmental impact is measured in terms of carbon dioxide equivalent emissions (kgCo2e) or global warming potential (GWP). The model was applied to an existing reinforced concrete trough bridge, which is a structure type commonly used in Swedish railways. Results show that that the model was effective and simple for investigating the environmental impact of the studied structure. 

Estimation of restraint is very important for accurately predicting the risk of early thermal and shrinkage cracking in concrete structures. The stress in young concrete is affected by changes in its dimensions during hydration and the restraint imposed by adjoining structures. In concrete culverts, the restraints from existing structures acting upon the first and second casting sections to be cast are different, causing them to exhibit different early cracking behaviour. This work presents a new method for predicting restraint in complex concrete structures using artificial neural networks (ANNs). Finite element calculations were performed to predict restraint in 108 slabs, 324 walls and 972 roofs from second sections of concrete culverts, and the results obtained were used to train and validate ANN models. The ANN models were then used to study the effects of varying selected parameters (the thickness and width of the roof and slab, the thickness and height of the walls, and the length of the culvert section) on the predicted restraint. Mathematical expressions for predicting restraint values in slabs, walls and roofs were derived based on the ANN models’ output and implemented in an Excel spreadsheet that provides a simple way of predicting restraint in practical applications. Restraint values predicted in this way agree well with the results of finite-element calculations

Concrete cracks in structures such as water tanks and nuclear power stations cause anxiety to owners, contractors and engineers. These cracks may significantly increase the structure’s permeability and thus increase leakage, reduce durability, and eventually lead to loss of structural functionality. Therefore it is important to minimize their occurrence and size. To identify effective ways of minimizing cracking in young concrete segments, a parametric study was conducted using the finite element method (FEM). Parameters considered include casting sequence, joint position, wall height, and cooling. The study examined continuous and jumped casting approaches to the casting of a cylindrical reinforced concrete tank for a sewage-treatment plant, with and without the application of the ‘kicker’ technique in which the lower part of the wall is cast with the slab. The main cause of cracking is thermal change and restraint imposed by adjacent older structures, and the FEM predictions agree well with experimental observations. Continuous casting is most effective at minimizing cracking because it creates only two contact edges between newly cast and existing structures producing the lowest level of restraint. The kicker technique is shown to be very effective for reducing restraint and consider rephasing.

Volumetric changes in early age concrete that are restrained might lead to cracks. The degree of restraint is influenced by the casting sequence and the dimensions of the castings. In the current study a new casting technique is proposed to reduce restraint in the newly cast concrete with a new arrangement of the structural joint to the existing old concrete. The proposed technique is valid for the typical structure wall-on-slab using one structural joint. This casting method means that lower part of the wall is cast together with the slab, and that part is called a kicker. Hereby, the behavior of the structure changes from a typical case wall-on-slab to a typical case wall-on-wall. It has been proven by the beam theory and demonstrated by numerical calculations that there is a clear reduction in the restraint from the slab to the wall using kickers. In the paper different kicker heights are studied with the aim of determining the minimum restraint in the upper part of the wall cast in contact with the kicker. The technique using kickers is compared with common measures used in the field to avoid cracking, such as cooling pipes in the new casting and/or heating cables in the adjoining old concrete. The presented method is both cost and time effective, as it opens the possibility to use larger structural length of each casting sequence.

In addition to cement, sand, gravel, and water, the current investigation of the influence ofadditives on the compressive strength of concrete at 28 days includes fly ash, silica fume, andslag. 315 concrete compositions with various amounts of additives are trained and tested using anartificial neural network. Concrete strength is largely affected by the specific gravity of cementand the specific gravity of fine and coarse particles, according to the studies. For greatercompressive strength, it is preferable to use materials with a higher specific gravity. Compressivestrength has grown as the amount of silica fumes has increased. Increased amounts of slag orsuper-plasticizer resulted in the same behavior. When the amount of fly ash was increased, thecompressive strength of the material decreased.

Reinforced concrete (RC) walls have been widely used in different types of civil engineering projects. Therefore, their behaviour under several kinds of loading is of utmost importance. In this study, the main objective is to investigate the behaviour of RC Vierendeel walls under the applied loads by employing numerical analyses for the studied walls. Several assumptions are adopted in these analyses to simulate the actual behaviour of Vierendeel walls, which were experimentally studied in previous investigations. The numerical results showed that the simulated numerical behaviour has a very good agreement with the experimental results of the tested models. Statically, this agreement is validated and verified in terms of the mean and standard deviation values. Therefore, the proposed numerical models and assumptions are the suitable ones to simulate the structural behaviour of these walls under the applied conditions. The structural behaviour is presented in terms of load capacity, crack pattern, deflection, and mode of failure. The results show that the reactive powder concrete (RPC) models have more resistance under the applied load in terms of deflection, cracks, and ductility index than the models of normal strength concrete (NSC). Also, the openings are the main reason for the diagonal cracking at the corners of the RC walls. The deflection in all models is a single curvature. The mode of failure for all models is shear.  

The addition of polymer to a base binder has been documented as a successful approach in terms of improving physical and rheological properties of the base bitumen. However, the main drawbacks of polymer-modified bitumen are incompatibility and degradation of polymer due to aging. This article aims to introduce a bibliometric analysis and review on modifying bitumen with polymers. Additionally, this article intent to highlight the significant gaps and recommendations for future work. Furthermore, another objective of this article is to provide a worth attempt regrading reducing the negative impact of polymer’s drawbacks on the performance of polymer-modified base binder. The findings of this article demonstrated that the test of storage stability for polymer-amended bitumen should be modified, in which the softening point of aluminum tube centerpiece should be measured to introduce a better evaluation for the storage stability of polymer-amended bitumen. In addition, the effects of kinetic factors (mixing sequence, viscosity of blend, shear rate, and time of mixing) on the compatibility of polymer-amended bitumen should be investigated. Moreover, the addition of compatibilizers and stabilizers to polymer-modified binder is recommended to improve compatibility and reduce the effect of aging on degradation of polymer.

In the fast-expanding construction industry worldwide, building information modelling (BIM) is a robust process. However, to date, developing countries are not very well adopting the techniques proven to help significantly produce effective management of construction projects. This study reviews numerous current studies conducted on the challenges and benefits of adopting BIM. It aims to identify the challenges and benefits of BIM. Additional focus was given to developing countries since fewer documented articles were found in the literature. However, many challenges are identified which hinder BIM adoption to full potential, particularly in developing countries. The most common findings proposed five critical benefits of BIM adoption, namely: i) improved data management (rich) information; ii) improved visualization of project execution; iii) clash detection; iv) reducing waste in the material; v) reducing the financial risk associated with the project in order by obtaining earlier reliable cost estimates. Likewise, the most common findings defined five major BIM adoption obstacles are: i) resilience to change industry culture; ii) high Investment cost; iii) lack of client demand; iv) absence of stakeholder collaboration; v) lack of awareness. It was found that there is a considerable benefit gained by those construction organizations already practicing the information modelling. Most of the organizations that adopted BIM are situated in European countries, followed by the united states of America. Thus, future work should focus on how to raise the level of awareness and general adaptability, especially in developing nations.

The production of concrete by incorporating a microorganism has emerged as a promising research area, offering potential benefits such as reduce carbon footprint, enhance durability and increased strength. The present study reported for the first time using a fungal strain (Aspergillus iizukae EAN605) in biocementation. The study aims to investigate the effectiveness of incorporating Aspergillus iizukae EAN 605 into foam concrete to improve its performance, particularly its strength. The study employs the response surface methodology (RSM) to explore the relationship between density, microorganism concentration and water /cement ratio (w/c) and their effects on compressive strength. Through a series of experiments,the highest recorded compressive strength was achieved with a density of 1800kg/m3, w/c ratio of 0.5, and Aspergillus iizukae EAN605 concentration of 0.5g/l, resulting in a remarkable 37.5% increase compared to foam concrete (FC). The variables of density, A. iizukae EAN 605 and their interaction density*fungi (D*F) significantly impacted compressive strength, with p-values of 0.000, 0.016, and 0.010, respectively.X-ray diffraction (XRD) analysis was employed to identify the crystalline composition of the precipitates formed on the fungal hyphae, providing insights into the mineralogical transformations occurring during the biocementation process. Additionally, scanning electron microscope (SEM) imaging was utilised to visualise the morphology and distribution of the calcite crystals, further supporting the evidence of fungal-mediated mineral precipitation in foam concrete. The findings of this study hold significant implications for the concrete industry, as the incorporation of Aspergillus iizukae EAN605 in foam concrete offers a sustainable solution to enhance compressive strength and contribute to environmental friendly construction practices. This study provides valuable insights for future research and practical applications in the field of bio-foamed concrete (B-FC).

This paper aims to elucidate the clear visibility of attenuating seismic waves (SWs) with forest trees as natural metamaterials known as forest metamaterials (FMs) arranged in a periodic pattern around the protected area. In analyzing the changeability of the FM models, five distinct cases of “metawall” configurations were considered. Numerical simulations were conducted to study the characteristics of bandgaps (BGs) and vibration modes for each model. The finite element method (FEM) was used to illustrate the generation of BGs in low frequency ranges. The commercial finite element code COMSOL Multiphysics 5.4a was adopted to carry out the numerical analysis, utilizing the sound cone method and the strain energy method. Wide BGs were generated for the Bragg scattering BGs and local resonance BGs owing to the gradual variations in tree height and the addition of a vertical load in the form of mass to simulate the tree foliage. The results were promising and confirmed the applicability of FEM based on the parametric design language ANSYS 17.2 software to apply the boundary conditions of the proposed models at frequencies below 100 Hz. The effects of the mechanical properties of the six layers of soil and the geometric parameters of FMs were studied intensively. Unit cell layouts and an engineered configuration for arranging FMs based on periodic theory to achieve significant results in controlling ground vibrations, which are valuable for protecting a large number of structures or an entire city, are recommended. Prior to construction, protecting a region and exerting control over FM characteristics are advantageous. The results exhibited the effect of the ‘trees’ upper portion (e.g., leaves, crown, and lateral bulky branches) and the gradual change in tree height on the width and position of BGs, which refers to the attenuation mechanism. Low frequency ranges of less than 100 Hz were particularly well suited for attenuating SWs with FMs. However, an engineering method for a safe city construction should be proposed on the basis of the arrangement of urban trees to allow for the shielding of SWs in specific frequency ranges.

The construction sector is a major contributor to global greenhouse gas emissions. Using recycled and waste materials in concrete is a practical solution to address environmental challenges. Currently, agricultural waste is widely used as a substitute for cement in the production of eco-friendly concrete. However, traditional methods for assessing the strength of such materials are both expensive and time-consuming. Therefore, this study uses machine learning techniques to develop prediction models for the compressive strength (CS) of rice husk ash (RHA) concrete. The ML techniques used in the present study include random forest (RF), light gradient boosting machine (LightGBM), ridge regression, and extreme gradient boosting (XGBoost). A total of 348 values of CS were collected from the experimental studies, and five characteristics of RHA concrete were taken as input variables. For the performance assessment of the models, multiple statistical metrics were used. During the training phase, the correlation coefficients (R) obtained for ridge regression, RF, XGBoost, and LightGBM were 0.943, 0.981, 0.985, and 0.996, respectively. In the testing set, the developed models demonstrated even higher performance, with correlation coefficients of 0.971, 0.993, 0.992, and 0.998 for ridge regression, RF, XGBoost, and LightGBM, respectively. The statistical analysis revealed that the LightGBM model outperformed other models, whereas the ridge regression model exhibited comparatively lower accuracy. SHapley Additive exPlanation (SHAP) method was employed for the interpretability of the developed model. The SHAP analysis revealed that water-to-cement is a controlling parameter in estimating the CS of RHA concrete. In conclusion, this study provides valuable guidance for builders and researchers to estimate the CS of RHA concrete. However, it is suggested that more input variables be incorporated and hybrid models utilized to further enhance the reliability and precision of the models.

Resin-based dental composites are promising tooth-resembling materials in restorative dentistry. The limited longevity of dental composite restorations due to the bulk/marginal fracture and secondary caries as well as possible health risks are the critical challenges faced by such materials. Therefore, developments of resin-based dental composites received considerable attention in academic researches for clinical applications. A comprehensive review of the recent developments in the scientific literature on resin-based dental composites is presented in this article. Firstly, in the article, the challenges in dental composites are introduced and then the chemical aspects of the systems are classified through a review of employed resins. Subsequently, the different characteristics related to the fillers employed for the development of the resin-based dental composites are described. Finally, conclusions are drawn and future insights are proposed. This article provides an insight that paves the way for tailoring and designing resin-based dental composites for clinical applications.

Polymer microcapsules containing cyanoacrylates have represented a promising option to develop self-healing biomaterials. This study aims to develop an electrospray method for the preparation of capsules using poly(methyl methacrylate) (PMMA) as the encapsulant and ethyl 2-cyanoacrylate (EC) as the encapsulate. It also aims to study the effect of the electrospray process parameters on the size and morphology of the capsules. The capsules were characterized using Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). Moreover, the effects of electrospray process parameters on the size were investigated by Taguchi experimental design. FTIR and TGA approved the presence of both PMMA and EC without further reaction. FE-SEM micrograph demonstrated that an appropriate choice of solvents, utilizing an appropriate PMMA:EC ratio and sufficient PMMA concentration are critical factors to produce capsules dominantly with an intact and spherical morphology. Utilizing various flow rates (0.3–0.5 ml/h) and applied voltage (18–26 kV), capsules were obtained with a 600–1000 nm size range. At constantly applied voltages, the increase in flow rate increased the capsule size up to 40% (ANOVA, p ≤ 0.05), while at constant flow rates, the increase in applied voltage reduced the average capsule size by 3.4–26% (ANOVA, p ≤ 0.05). The results from the Taguchi design represented the significance of solution flow rate, applied voltage, and solution concentration. It was shown that the most effective parameter on the size of capsules is flow rate. This research demonstrated that electrospray can be utilized as a convenient method for the preparation of sub-micron PMMA capsules containing EC. Furthermore, the morphology of the capsules is dominated by solvents, PMMA concentration, and PMMA:EC ratio, while the average size of the capsules can be altered by adjusting the flow rate and applied voltage of the electrospray process.

The extant body of literature articulates a noticeable disparity in the susceptibility to cracking and concomitant material degradation between alkali-activated composites (AAC) and ordinary Portland cement (OPC), predominantly attributable to shrinkage and subsequent drying phenomena. This divergence derives from the nanoscopic porosity of AAC binders, which is substantially finer than their OPC counterparts. However, experimental research validates that the judicious incorporation of alternative cementitious materials and fibrous reinforcements enriches the shrinkage characteristics of AAC, thereby enhancing its overall structural performance. Given the crucial role of shrinkage in defining the material integrity of AAC, especially under constrained environmental conditions, an in-depth understanding of shrinkage mechanisms materializes as a necessity for conceiving efficient shrinkage-mitigating strategies. In light of the growing interest in optimizing AAC through various material integrations and methodological innovations aimed at shrinkage diminution, this scholarly review undertakes an extensive synthesis of the laboratorial investigations focused on AAC shrinkage behavior and mitigation. However, this article critically evaluates widespread strategies for shrinkage mitigation, explicating their operative mechanisms. Moreover, it is outlined gaps in the existing research paradigm, promoting for targeted scholarly endeavors to yield a more clear understanding of shrinkage dynamics and to facilitate the advancement of environmentally sustainable AAC composites. Meanwhile, this study intended to consolidate existing research on developing trends in order to gain a comprehensive understanding of the possible uses of AACs and identify viable strategies for addressing AAC shrinkages. By addressing the challenges related to micro-cracking and shrinkage, the long-term durability of AACs may be improved, leading to increased adoption of these materials as sustainable building options in the construction industry today.

Four furnace tests have been performed using two different parametric fire curves and the results are compared with computer simulations and Eurocode calculations. What differentiates the parametric fire curve from other fire curves is in particular the cooling phase, something that has proven to be hard to model for timber structures.

A literature study and computer simulations were followed by experimental work performed at SP Wood Building Technology in Stockholm. The computer simulations were performed using the computer code TASEF. The predictions from TASEF were compared with measurements from the fire tests to evaluate how well the program can predict temperature distribution using a parametric fire curve.

The four fire tests were executed at SP Wood Building Technology, glued laminated timber beams were used in all tests. When preparing the test specimens thermocouples were installed to measure temperature distribution, the thermocouples were installed in drilled holes. A deviation study regarding these drill-holes was performed as a part of the preparations. The temperature distributions measured during the tests were compared with the temperature distribution predicted by TASEF.

Charring rate and charring depth were obtained from the fire tests, from the TASEF simulations but also by using equations given in the Eurocode. Since TASEF simulates temperature distribution and not charring depth, the 300 °C isotherm was assumed to represent the charring depth. The results from all three methods were compared and evaluated.

The agreement between experiments and TASEF predictions regarding temperature distribution and charring depth were in general very good. Parametric fire curves with opening factors of 0.02 m^1/2 and 0.04 m^1/2 were used in four fire tests. TASEF performed more accurate predictions regarding the temperature distribution for the small opening factor but looking at the charring depth the predictions were better for the bigger opening factor. It is recommended to perform further studies and find out the reason for this behaviour.

Comparing the charring depths measured at the tests with values calculated using Eurocode 5 there were some differences in charring depths. Charring depths for the horizontal direction of the beams were much alike, but when comparing the charring depths for the vertical direction there is a significant difference. The equations regarding charring depth for wood exposed to parametric fire curves in Eurocode 5 underestimate the charring depth. It is recommended to evaluate these equations further.

For one of the timber beams delamination occurred, this has previously been assumed not to occur to glued laminated beams. More studies should be performed regarding delamination of glued laminated beams exposed to fire.

In early 2020, cracks were discovered on the bridge crossing the Torne River at Autio. This resulted in an investigation being launched to determine the structural state of the bridge. In conjunction with this investigation, monitoring equipment was installed on the bridge, which enabled the collection of measured strain at four critical points on the bridge. 

In this thesis the measured strain was used to approximate stresses in the prestressing cables and thereby calculate the effects of fatigue on the bridge. Two different structural standards were used to calculate the results: Eurocode 2, and fib Model Code 2010. Likewise, two different cycle-counting methods were used to calculate the results: the Rainflow-algorithm, and the largest-magnitude approach. 

Regardless of structural standard or cycle-counting method, the results indicate that the effects of fatigue are neither an issue for the bridge, currently, nor will it be in the expected lifetime of the bridge.

Steel is a material commonly used in various constructions such as high-rise buildings, sport arenas, ships etc. Steel is a versatile building material due to its isotropic characteristics, e.g. both high tensile- and compressive strength. This allows steel to be formed into open section profiles which reduces material usage but simultaneously allows the tensile- and compressive stress resistance to be high in directions were loads are applied. Although steel has a high stress resistance its sensitivity to fire is larger than other building materials due to its high thermal conductivity. The strength of the material is reduced at higher temperatures and thereby makes the dimensioning of beams in fire cases vital in fire safety design of structural elements.

An aspect to consider when dimensioning open section building elements in steel is the shadow effect. The shadow effect is the result of the open cross-section geometrical shape of beams and columns, e.g. H-profiles. The interior of the profile is screened from thermal radiation caused by fire which makes the characteristics of the thermal exposure different from closed cross-section profiles. A common way to estimate the temperatures of steel after a certain time of fire exposure is to use numerical calculations described in Eurocode. In these calculations the shadow effect is applied as a reduction of the total heat exchange, i.e. both convection and thermal radiation, from the fire exposure.

A more realistic approach is to separate these boundary conditions and treat them as independent quantities. Wickström (2001) argues that a void is created within the flanges and that reduction factor thereby only should be applied to the radiative part of the total heat exchange, acting as a reduction of surface emissivity within the profile. This, since the convection is not affected by the shadow effect. Wickströms (2001) suggestion of application has been investigated in this thesis and has showed a better correlation than the approach suggested in Eurocode when compared to experimental tests.

Shadow effects calculated on the premises of separated boundary conditions for the total heat exchange has of yet only been investigated in detail with TASEF+-simulations, but these simulations predicts steel temperatures with satisfactory results. It is possible to reproduce a similar setup in the program COMSOL Multiphysics in two-dimensional simulations, and further three-dimensional simulations. This possibility has been investigated in this thesis.

COMSOL Multiphysics has proven to be an adequate tool when it comes to simulate fire exposure on slender steel beam with shadow effects considered. Both three- and two-dimensional models produced simulation results correlating well to simulations conducted in TASEF. Additionally, adequate correlations with experimental tests were obtained for COMSOL Multiphysics as well. Further work regarding fire simulations with the utilisation of COMSOL Multiphysics is thereby suggested.

A pre-flashover fire is very different from a post-flashover fire. The main difference is that in a pre-flashover fire the gas temperature and the radiation temperature differ. One thing that makes it a lot different is that the thermal exposure induced by a pre-flashover fire is largely affected by the smoke gas layer. These smoke gases can be very hot and therefore they emit heat radiation to their surroundings. The theory used, to calculate the thermal exposure of a pre-flashover fire, in this thesis relies on using thermal resistances to describe the heat transfer from the smoke gases. By doing so it is possible to calculate the temperatures of the smoke gases and the surfaces in touch with the smoke gases. Another approach is to use CFD software to numerically calculate the temperatures and in this thesis the two-zone model are compared to FDS, a CFD software. The two-zone model are also compared to a reduced-scale test. The comparisons gave good results, the two-zone model produced similar results compared to re reduced-scale test and FDS. This method of calculating thermal exposure can thereby be used to evaluate evacuation safety and save a lot of calculation time compared to calculating the thermal exposure with CFD software such as FDS.

Nowadays there is a main concern that should always be present in our minds; it is important to integrate and reconcile the economic, social and environmental aspects within a holistic and balanced sustainable development framework.Therefore, the construction sector has been facing a profound change in the materials used, new processes and approaches. According to this new aim, a new concept of structures had been born; the Affordable Houses.A concept is more often seen as an abstract idea of something, being it materialization always faced as a challenge. Therefore the challenge of this thesis is to create a system that could be able to erect, literally, a structure and, simultaneously, create conditions for the construction of a building, through the appliance of the concept of Modular Houses and Top Down Construction.For the implementation of these new concepts two case studies were created for the construction of a student residential building in Coimbra and Luleå. These case studies are integrated in different environments and socio-economic conditions, which will allow the assessment of this study to a more global application.This study was developed within the scope of a partnership between the University of Coimbra and Luleå University of Technology and was supervised by Professor Luís Simões da Silva (UC) and Professor Milan Veljkovic( LTU).

Having in mind the topic of industrialised construction and the benefits of modular construction, sandwich panels are investigated to be utilised as load-bearing wall elements. To assess its full potential, the present paper tackles the linear elastic buckling response of axially loaded angle sandwich panels, by means of numerical and analytical calculations, as the upper bound of its load bearing capacity. The failures modes are obtained and framed for concentrically loaded angle panels with fixed and pin-ended supports. A parametric study of the angle panel comprising a series of finite element models is undertaken where responses are compared with analytical calculations based on the theory of sandwich panels. Boundaries for local and global buckling are identified and framed.

This paper introduces a novel joint based on a friction connection designed for column-splices. The jointwas developed within the scope of modular construction to improve the fast assembly of prefabricatedframes and to accommodate eventual misalignments. Gaps at the connection are considered on the jointhorizontal and vertical axis to accommodate misalignments whether they are rotations and/ordisplacements and so to allow for the easy fit of the columns. The efficiency of the joint resistance basedon different connection gaps subjected to uniform compression is assessed.

Sweden has a strong demand on the construction of student accommodations and consequently significant efforts have been taken to increase and streamline construction methods. In addition, the fluctuation on the number of students admitted at each year, in each university, lead to periods of house shortage or, in opposition to that, to eventual surplus on the housing market. For these reasons urges finding a fast execution process in construction to fulfil the market needs, together with a housing mechanism of control which balances the students’ needs with the housing availability. In this sense, the Frameup system arises as a solution to solve both problems by combining a modular construction with an innovative execution process.

The FRAMEUP buildings uses a steel frame in combination with prefabricated 3D modules - fully equipped and suitable for student accommodations – which are assembled by starting from the roof to the 1^st floor. The existence of the lifting system permits the erection of the building, promoting each time the building is lifted, a clearance of one-floor-height, at ground level, for the assembly of a new floor. The procedure is repeated several times, according to the number of floors, until the 1^st floor of the building, the last floor of the execution sequence, is assembled.

Alongside with its advantage on the fast execution, the Frameup system allows to efficiently increase or decrease the number of the floors and consequently its exchangeability with other buildings of same nature. Thus, assuming a net of FRAMEUP buildings at each university, its exchangeability system would create the necessary conditions so that the number of floors at each campus would follow the fluctuations of the students’ population among the different universities on different periods of time, so to suppress the needs for housing or to avoid the surplus on construction.

Rice husk biochar was added to polylactic acid (PLA) to create a biocomposite filament suitable for the extrusion-based 3D printing process of fused deposition modelling (FDM). Taguchi L16 was used for experiment design, and the significance of process parameters was determined using variance analysis (ANOVA). For a 0.3-mm layer thickness, the addition of 5 wt.% biochar resulted in ultimate tensile strength and a modulus of elasticity of 36 MPa and 1103 MPa, respectively. The addition of biochar had a negative influence on flexural strength. The maximum flexural modulus was obtained with 3 % biochar, 100 % infill density, and 0.1 mm layer thickness. Particularly, 1 % biochar resulted in a considerable increase in impact strength, while a subsequent rise in biochar resulted in a decrease, probably due to the agglomeration effect. For 3D printed neat PLA, the average tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength observed were 19 MPa, 550 MPa, 54 MPa, 1981 MPa, and 25 KJ/m2, respectively. Additionally, considering the output of each test, a multicriteria decision-making model, namely, TOPSIS, has been utilized for ranking the mechanical performance. In order to optimise the mechanical properties of three-dimensional printed objects, the study suggests a layer thickness of 0.2 mm, an infill density of 100 %, and raster angle of 0° as the FDM process parameters.

EFLA og Luleå Tekniska Universitet har bistått Agder fylkeskommune med forsterkning av to gamle stålbjelkebruer i Agder fylke, som dannet en flaskehals for vegtransport i området. I prosjekteringen er det brukt en metode som aldri har vært brukt i Norge før, og den har vist seg å være effektiv i forhold til kostnad, gjennomførbarhet og miljøpåvirkning. Prosjektet er et eksempel på vellykket nordisk samarbeid, og kan ha overføring til fremtidige prosjekter

A requirement for heavier vehicular transport on the Norwegian road network has resulted in a demand for increased bearing capacity for many of the older bridges in the country. Many of the bridges that have been found to have insufficient capacity against present-day demands are steel girder bridges with concrete slabs without a shear connection between steel and concrete. There is a large number of bridges of this type in Norway and the paper presents strengthening of two of those, in Aust-Agder county in the south of the country. These bridges are approximately 30 m long, single span. The bearing capacity has been upgraded by installing composite action between the steel girders and the concrete slab using coiled pins, in conjunction with thickening of the bottom flange of the steel girders. To obtain composite action, the pins are fitted to tightly drilled holes through the top flange of girders up into the concrete slab. Coiled pins have not been used much for bridge applications. In the work presented, the method has been found to have advantages in terms of cost and workability. Furthermore, the method has benefits when viewed from an environmental standpoint, since it allows strengthening of existing non-composite bridges using relatively little new material, and minimizes traffic disruptions.

This paper examines the reaction-to-fire behaviour of building materials containing phase change materials by predicting their fire classification according to the European reaction-to-fire classification system (Euroclasses). While various building materials containing PCMs exist today, their application in buildings has been somewhat limited due to the fire behaviour of these building materials. Existing research has focused on small scale testing which does not allow determination of the Euroclass of the material. In this application, large scale performance is predicted based on previously published small scale data to provide some valuable insights into the expected fire performance of these materials. As a starting point, a systematic literature review on phase change materials (PCM) and fire behaviour was conducted, with the purpose of identifying all existing literature concerning experimental investigation of the fire behaviour of building materials containing PCMs. In total, 816 articles were selected from the literature search. After screening of these papers, 51 articles were fully reviewed and included in the next step of the study. In the next step, the reaction-to-fire behaviour of the building materials with PCMs that were identified from the literature was predicted using the ConeTools simulation program. The input data required for ConeTools was obtained from the identified literature. Initially, 27 of the 51 studies used cone calorimetry as a fire testing method and could therefore be considered for the Euroclass assessment. However, of the 27 studies, only 17 studies provided information on both the heat release rates (HRR) and time to ignition (TTI) and were selected for use in the ConeTools program. The ConeTools program predicted Euroclasses for all the building materials containing PCMs from the selected 17 studies. The predicted Euroclasses for most materials was low (i.e. fire classes ‘D' or ‘E or worse') which confirms that materials containing PCMs generally have a low react-to-fire behaviour even with addition of flame retardants (FR). Our findings indicate that the fire behaviour, typically Euroclass ‘D' or ‘E or worse', of the building materials containing PCMs is indeed a barrier to their implementation in the building applications where Euroclass C or higher is required, e.g. in evacuation pathways or certain public spaces. The predictions of the Euroclasses based on ConeTools need to be confirmed using Single Burning Item tests (EN 13823) and/or Room Corner tests (ISO 9705) in the future, to enable a better understanding of fire behaviour of these building materials.

Using rice husk ash (RHA) as a cement substitute in concrete production has potential benefits, including cement consumption and mitigating environmental effects. The feasibility of RHA on concrete strength was investigated in this research by predicting the split tensile strength (SPT) and flexural strength (FS) of RHA concrete (RHAC). The study used machine learning (ML) methods such as ensemble stacking and gene expression programming (GEP). The stacking model was improved using base learner configurations ML models, such as, random forest (RF), support vector regression, and gradient boosting regression. The proposed models were validated by statistical tests and external validation criteria. Moreover, the effect of input parameters was investigated using Shapley adaptive exPlanations (SHAP) for RF and parametric analysis for GEP-based models. The analysis revealed that the stacking ensemble integrates base learner predictions and demonstrated superior performance, with R values greater than 0.98 and 0.96. Mean absolute error and root mean square error values for both SPT and FS were 0.23, 0.3, 0.5, and 0.7 MPA, respectively. The SHAP analysis demonstrated water, cement, superplasticizer, and age as influential parameters for the RHAC strength. Furthermore, the SPT and FS of RHAC can be predicted with an acceptable error using the GEP expressions in the standard design procedure.