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Fiber-Reinforced Geopolymer Composites (FRGCs) typically use mono-fiber reinforcement, often overlooking the potential benefits of hybrid fibers. This article examines the effects of different PVA fibers (thick and thin) and steel fibers (straight, hooked, and recycled tire wires) on the performance of one-part geopolymer composites. The study evaluates the impact of singular and hybridized PVA and steel fibers on slump flow, mechanical properties (compressive and flexural strength), and post-crack flexural behavior (first-crack strength, ductility index, and flexural toughness). Key parameters include the average number of fibers crossing a unit area (Ns) and the fibers' Young's modulus (YM). Findings reveal that Ns is crucial for enhancing post-crack behavior, while YM significantly improves compressive and flexural strength in FRGCs. Steel fibers increased compressive strength by 18% (straight), 12% (hooked), and 8% (recycled tire wires), whereas PVA fibers slightly reduced it by 4% (thick) to 14% (thin). However, hybrid fiber configurations balanced the compressive strength loss from PVA fibers. Flexural strength improved with fiber inclusion, regardless of type and geometry, ranging from 6.4 MPa (2% thick PVA fibers) to 10.25 MPa (1% thin PVA fibers & 1% straight steel fibers), a 23%–97% increase over control mixes. Composites with recycled steel fibers showed exceptional post-crack behavior, with mono Recycled Tire Wire (RTW) composites having superior ductility indices (13.3) compared to mono straight and hooked steel fibers. Additionally, RTW combined with thin PVA fibers demonstrated exceptional flexural toughness (21.13 N m) and ductility indices (28.6), indicating superior post-crack performance compared to virgin counterparts. This study underscores the potential of hybrid virgin and recycled fiber-reinforced FRGCs to enhance mechanical and post-crack performance, offering a sustainable pathway for construction materials with reduced environmental impact. The research also develops linear models predicting mechanical properties, providing valuable tools for optimizing FRGC formulations.

Geopolymer cement is being viewed as an environmentally sustainable substitute for Ordinary Portland Cement (OPC) in oilwell cement. The study examines the impact of varying graphene oxide (GO) concentrations on the mechanical properties of the geopolymer cement. The optimal sodium hydroxide molarity, alkaline activator ratio and GO’s concentration were optimized using Response Surface Methodology based on Central Composite Design to obtain maximize compressive strength formulation. The results show that the highest concentration of GO or the highest molarity of sodium hydroxide can yield the highest strength. Besides, the GO concentration of 0.2% by weight of fly ash (bwof) demonstrate a non-settling and time-independent fluid behaviors at the average test temperature. The formulation results in a 22.9% lower filtrate volume compared to the reference design without GO. The study highlights GO as potential sustainable performance enhancer in geopolymer cement for elevated oilwell condition.

Implementing Internet of things (IoT) technology in the context of intelligent buildings and infrastructure development has garnered significant attention within the construction sector. Nonetheless, the implementation of IoT could be improved by assessing various barriers. The purpose of this study was to examine the obstacles related to the adaptation of IoT techniques within the construction sector, as well as the effects on the advancement of intelligent building and infrastructure systems. The study employed a mixed-method approach involving exploratory factor analysis (EFA) and structural equation modeling (SEM) to determine six types of barriers: knowledge, technical, standardization, creativity, complexity, and economics. The study revealed that the implementation of IoT for developing smart construction and infrastructure in the construction sector was significantly influenced by all six constructs. The results of this study offer significant ramifications for the field. The study underscores the necessity for heightened consciousness and instruction regarding the advantages of implementing IoT. The study posits that the technical barriers, including interoperability, modernization of legacy infrastructure, and coordination and collaboration difficulties, require attention from the industry. The study highlights the significance of establishing industry-wide standards and protocols for implementing IoT and regulatory and legal frameworks. Finally, the study underscores the necessity for augmented funding and financing options for IoT endeavors. Subsequent study endeavors may expand upon the present findings by delving into the barriers encountered by alternative sectors and nations and assessing the efficacy of the suggested measures in this investigation.

A crucial aspect of the design approach for bar-reinforced concrete buildings is the proper transfer of loads between the concrete and steel reinforcement via bonding. Bar pull-out tests were done to see how graphene oxide (GO) affected the bond strength, bond energy, and bond stress–slip response of deformed reinforcing bars implanted in engineered cementitious composites (ECC). This was done to improve the bond strength of steel/concrete composites. This article examines the bonding behaviour of steel reinforcing bars in a mixture of GO-modified ECC. The findings of pull-out assessments conducted on two distinct diameters (12 and 16 mm) of reinforcement steel bar inserted in ECC are initially provided. The investigation's findings are then utilised to determine the bond-slip interactions that describes the relations between the ECC mixtures and steel reinforcement bars. According to the experiment results, the introduction of GO as a nano-reinforcement in the ECC mixture had a considerable positive effect on the bar-matrix interactions owing to its bridging function. After 28 days, the bond strength of steel bars with widths of 12 and 16 mm was increased by 54.80% and 26.70%, respectively, when 0.05 wt% of GO was added to 1% of PVA fibre. The response surface methodology (RSM) is employed for developing predictive algorithms, which are then utilised in performing multi-variate optimization on bond-slip parameters, including bond strength, bond slip and bond energy. The acquired actual and predicted findings suggest that the created models are adequate for interpreting the bond performance of reinforcement steel bars in the GO-ECC.

Polyurea coatings are well recognized for their remarkable protective properties, making them highly appropriate for practical use in the field of concrete building. The use of polyurea coatings in the concrete building business is currently constrained, despite its prevalent application in industrialized nations. The limited use may be ascribed to ambiguities about the determinants of effective implementation in this particular setting, as well as the dearth of extensive study in the realm of new building materials. The primary objective of this research is to assess and conceptualize the key determinants linked to the use of polyurea coatings in concrete building endeavors. Utilizing a quantitative research approach, a comprehensive literature analysis was conducted to identify a total of 21 probable success variables. The reliability of the questionnaire was established by the administration of a pilot survey, and afterwards, an exploratory factor analysis (EFA) was performed to enhance the clarity and precision of the underlying components. The researchers used structural modeling (SEM) approaches to develop a robust model using the primary data obtained from the questionnaire survey. The EFA revealed the presence of five unique constructs that have an impact on the effectiveness of polyurea coatings in concrete building projects. These constructions comprise several characteristics, including environmental considerations, functional requirements, protective properties, execution processes, and creative elements. The significance and relevance of this research are shown by the validation of the study's results using SEM. The study makes a valuable contribution towards the progression of polyurea coating use within the concrete building sector.

The transformational potential of 3D printing within the manufacturing industry has been widely recognized. However, its widespread adoption faces significant practical challenges that extend beyond the technology itself, encompassing political, economic, social, and technical (PEST) factors. This research investigates the external variables impacting the successful implementation of 3D printing and proposes strategies to overcome these barriers. Through exploratory factor analysis (EFA) and structural equation modeling (SEM), we identified key external factors, including governmental regulations, economic conditions, societal acceptance, and technical readiness, that significantly influence the success of 3D printing deployment. Notably, addressing technological barriers emerged as a crucial factor. To address these implementation challenges, we recommend increased public awareness and stakeholder participation. Our findings indicate that these strategies can enhance the prospects of 3D printing adoption. These results hold significant implications for policymakers, practitioners, and researchers in the 3D printing industry. Understanding and mitigating external obstacles are critical for harnessing the benefits of 3D printing within a dynamic environment. This research sheds light on the multifaceted challenges surrounding 3D printing implementation, emphasizing the importance of proactive measures to overcome these hurdles.

In recent times, there has been a notable increase in the focus on the use of Building Information Modelling (BIM) within the Architecture, Engineering, and Construction (AEC) industry. This study aims to fill a notable void in the current body of literature by examining the connections between the implementation of BIM and the factors that influence it. Additionally, it investigates the resulting effects on collaboration, continuous improvement, data management, gradual adoption, standardisation, and the various dimensions of society, economy, politics, and technology. This study examines the impact of BIM adoption within the AEC sector, focusing on its external environment by using a Political, Economic, Social, and Technological (PEST) approach. Using a quantitative approach, data was gathered by means of a survey questionnaire that was delivered to a sample of 216 professionals in the AEC business, who were chosen using purposive selection. The results suggest that the deployment of BIM cooperation, continuous improvement, effective data management, gradual acceptance, and standardisation, leading to positive outcomes in several areas such as social, economic, political, and technical. These findings have significant consequences for professionals working in the field.

This study aimed to identify and evaluate the primary safety factors that contribute to accidents in downstream oil and gas construction projects in Malaysia. A quantitative approach was used, including a pilot survey and a main survey of individuals involved in these types of projects. Exploratory factor analysis (EFA) was performed on the pilot survey data, and structural equation modeling (SEM) was conducted on the main survey results. The study identified several critical safety factors, including inadequate safety training, insufficient safety procedures, and inadequate supervision. The findings provide insights into the significant safety elements in Malaysia's oil and gas construction industry and may aid in improving both theoretical and practical aspects of construction safety in this field. This research helps to fill a gap in knowledge regarding construction safety in Malaysia's oil and gas sector by highlighting the most important contributors to accidents in this industry.

Engineered cementitious composite (ECC) is a fiber-reinforced cementitious composite material that has garnered considerable attention from the building and scientific sectors. However, ECCs offer improved mechanical and durability characteristics compared to regular concrete. Fibers serve a crucial function in producing ultrahigh tensile ductility and autogenous fracture width control inside the micromechanical reinforcing system of ECC. This research discusses the various proportions of polyvinyl alcohol fibers (PVA) as reinforcing materials by total volume fraction in ECC in terms of mechanical properties performance, environmental consequences, and economic effects. A total of 60 ECC samples were cast to achieve the targeted compressive strength of 45 MPa of ECC mixture reinforced with 1%, 1.5%, and 2% of PVA fiber by the volume fraction. Though, the best compressive of ECC is calculated by 62.60 MPa at 1% of PVA fiber at 28 days. Besides, the tensile and flexural strengths are enhanced by 5.20 MPa, and 11.15 MPa at 1% of PVA fiber in ECC for 28 days respectively. In addition, the density of ECC is reduced with rises in the content of PVA fiber while water absorption is increased as the percentage of PVA fiber growths in the ECC after 28 days respectively. Moreover, the embodied carbon and energy are improved when the PVA fiber by the volume fraction increases in the mixture. It has been observed that the use of 1% PVA fiber by the volume fraction in cementitious composites is offering maximum strength and less embodied carbon and energy, therefore, it has been recommended for structural application.

This study background highlights the increasing need for effective management of risks in tall buildings due to their complexity and potential hazards. BIM has been accepted as a potential solution for management of risks in tall buildings; however, its adaptation has been slow due to several obstacles. The purpose of this study is to identify and validate the impediments to the adaptation of BIM for management of risks. The study adopted a two-step methodology, consisting of exploratory factor analysis (EFA) and structural equation modelling (SEM). The data were collected through an online survey of professionals involved in design, construction, and management. Results of the study reveal six significant impediments: technical, integration, operational, creativity, privacy, and standardization. The findings provide theoretical contributions to the literature by identifying and validating the impediments to adaptation of BIM for risks in tall buildings. Practical implications suggest that organizations involved in design, construction, and management of tall buildings need to address the identified impediments to ensure successful adaptation of BIM for management of risks. This study contributes to the understanding of the obstacles to the adaptation of BIM for management of risks in tall buildings and provides insights for organizations to overcome these impediments.

Globally, large quantities of oily sludge are produced in petroleum refineries as wastes from petroleum refining processes. Petroleum refinery oily sludge (PROS) is a major by-product of the processes and a major contributor to pollution in the oil and gas industry. In this study, Response Surface Methodology (RSM) was used for optimising and modelling experimental work. Thermally treated PROS replaced fly ash (FA) at 5–20 % in geopolymer mortar mixes at a fixed combination of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). The visual observations and effects of PROS on the density and compressive strength of PROS geopolymer mortar (PGM) were studied. PGM with 10 % replacement of PROS had the maximum compressive strength of 38.17 MPa after 28 days. P-values obtained from the quadratic models developed for the synergistic effect of FA-PROS on density and compressive strength were less than 0.005. Optimisation of the synergistic effect of FA-PROS binder produced an optimal combination of both materials for maximum compressive strength and density of 2200 kg/m3 with desirability factor of 0.981. This investigation shows that replacing PROS with FA in geopolymer mortar can result in a new supply chain for greener binder materials in geopolymer mortar.

Industrialized construction continues to emerge globally. Developing countries like Malaysia are still unable to increase industrialized building system (IBS) implementation significantly, demonstrated by the low IBS percentage of less than 3%. Therefore, this research aims to determine the factors blocking IBS implementation through a mixed-methodological approach in the Malaysian construction industry. Using the data collected from 219 valid questionnaire responses, several statistical analyses were performed. Factor analysis was used to categorize the 25 factors into six main groups namely: “financial concerns,” “ineffective policies,” “technical and management worries,” “traditional stakeholders’ concerns,” “design restrictions” and “negative perception”. The top three critical factors are high initial capital cost, high initial cost of customized design, and transportation cost. Hence, adopting an innovative standardized design concept and increasing IBS manufacturers nationwide are recommended. The findings provide a useful guide to critical blocking factors and, thus, develop feasible solutions to achieve successful implementation of industrialized buildings.

Repair methods have been adopted to restore the integrity of structures and ensure their safety and longevity. Although jacketing is commonly adopted as a repair method, its implementation results in added loads and a reduction in dimensions and free spacing. In view of the challenges associated with the implementation of jacketing, the development of ultra-high-performance engineered cementitious composites (UHPECCs) are frequently discussed in research as this can enable jacketing to be performed using thin layers of repair material due to the higher strength-to-weight ratio of UHPECCs compared to conventional repair materials. Therefore, the adoption of UHPECCs for jacketing can reduce the overall weight and thickness of the repair material while ensuring the longevity of the repair. At the same time, graphene nanoplatelets (GnPs), which are carbon-derived nanoparticles, are well-known to be unique and advanced nanomaterials with superior properties. In light of the exceptional strength properties of GnPs, the effect of incorporating GnPs in engineered cementitious composites (ECCs) on strength was studied in an effort to further advance UHPECC research. Compressive and tensile strength tests were conducted on ECC samples that contain GnPs added in amounts ranging from 0.03 to 0.09% of the binder weight. The results reveal that the incorporation of GnPs improved strength: the strength of GnP-UHPECC increased as GnP content increased, and compressive and tensile strengths substantially increased by up to 32.9 and 64.6%, respectively.

This study explores the potential of antimicrobial agents in high-performance concrete (HPC) to combat biodeterioration without compromising compressive strength. Response surface methodology (RSM) was used to create 21 combinations of nanosized TiO2 and ZnO (ranging from 0–2% by weight of cement in HPC). Results show that ZnO negatively impacts compressive strength as its content increases from 0–2%, while TiO2 enhances it by up to 17% with 2% TiO2. By optimizing TiO2 and varying ZnO within the 0–2% range, compressive strengths between 81–100 MPa can be achieved. The quadratic model, with significant statistical values, accurately depicts the effects of nanoparticles on compressive strengths.

Accident analysis is used to discover the causes of workplace injuries and devise methods for preventing them in the future. There has been little discussion in the previous studies of the specific elements contributing to deadly construction accidents. In contrast to previous studies, this study focuses on the causes of fatal construction accidents based on management factors, unsafe site conditions, and workers' unsafe actions. The association rule mining technique identifies the hidden patterns or knowledge between the root causes of fatal construction accidents, and one hundred meaningful association rules were extracted from the two hundred and fifty-three rules generated. It was discovered that many fatal construction accidents were caused by management factors, unsafe site circumstances, and risky worker behaviors. These analyses can be used to demonstrate plausible cause-and-effect correlations, assisting in building a safer working environment in the construction sector. The study findings can be used more efficiently to design effective inspection procedures and occupational safety initiatives. Finally, the proposed method should be tested in a broader range of construction situations and scenarios to ensure that it is as accurate as possible.

The objective of this study was to evaluate the effect of graphene nanoplatelets (GnP) on the mechanical properties of concrete as well as the flexural performance of reinforced concrete (GnP-RC) beams. In the experimental campaign, several dosages of GnP (0.00%, 0.02%, 0.05%, 0.10%, 0.30%, and 0.50% wt of cement) were included in the concrete mixtures. First, the mechanical properties of concrete (compressive, tensile, flexural, and modulus of elasticity) were studied. A further experimental investigation was conducted on the flexural behavior of GnP-RC beams. The failure mode of beams, crack patterns, moment-curvature relationship, and ductility properties are reported. According to the observed results, GnP addition is capable of significantly improving mechanical properties. By adding 0.02% of GnP, both the compressive and tensile strengths were improved by 20.82% and 30.05%, respectively. Additionally, 0.02% of GnP also enhanced the cracking, yielding, and ultimate loads of beams by 36%, 23%, and 15%, respectively. Further, for the same concentration of GnP, the energy absorption and post-cracking ductility were improved by 25% and 20%, respectively. This report also presents analytical and statistical models for predicting the ultimate moment capacity of RC beams containing nano-reinforcement materials. The models have been demonstrated to be accurate at predicting the present and independent data.

In oil well cementing, cement must flow through the casing before reaching the targeted annulus; hence, a retarder must be added to provide the cement with sufficient time to reach the targeted depth before setting. At the same time, in support of the Paris Agreement, the prospect of substituting ordinary Portland cement (OPC) with geopolymer cement as the well cement material has to be further explored. Although previous studies have found that retarders can delay the strength development of the cement, the studies were conducted either under ambient conditions or using OPC; hence, the findings do not apply to geopolymer cement that is exposed to wellbore conditions. In order to address the shortcomings of the studies, an addition of a hydroxycarboxylic acid-based retarder to a fly ash-based geopolymer cement, at concentrations of up to 3% by weight of the fly ash, was performed. The slurry of the cement was aged at 100 °C and 20.7 MPa for 8, 24 and 48 h. Compressive strength tests were conducted on samples of the cement. At the 8 h aging duration, retarder concentrations of 0.5–2.0% led to strength increases of 112.7–129.4% relative to that of 0%, or the control sample, whereas that of 3.0% led to a strength decrease of 84.2%. At the 24 h aging duration, all retarder concentrations led to strength decreases of 16.4–22.5%. At the 48 h aging duration, retarder concentrations of 1.0–3.0% led to strength increases of 18.1–24.4%, whereas that of 0.5% led to a strength decrease of 16.7%.

Abstract The potassium (K) and sodium (Na) elements in banana are needed for hydration reaction that can enhance the strength properties of concrete. This research aims (a) to determine the material engineering properties of banana skin ash (BSA) and concrete containing BSA, (b) to measure the strength enhancement of concrete due to BSA, and (c) to identify optimal application of BSA as supplementary cement materials (SCM) in concrete. The BSA characterization were assessed through X-ray fluorescence (XRF) and Blaine’s air permeability. The workability, compressive strength, and microstructures of concrete containing BSA were analysed using slump test, universal testing machine (UTM) and scanning electron microscope (SEM). A total of 15 oxides and 19 non-oxides elements were identified in BSA with K (43.1%) the highest and Na was not detected. At 20 g of mass, the BSA had a higher bulk density (198.43 ± 0.00 cm3) than ordinary Portland cement (OPC) (36.32 ± 0.00 cm3) indicating availability of large surface area for water absorption. The concrete workability was reduced with the presence of BSA (0% BSA: > 100 mm, 1% BSA: 19 ± 1.0 mm, 2%: 15 ± 0.0 mm, 3% BSA: 10 ± 0.0 mm). The compressive strength increased with the number of curing days. The concrete microstructures were improved; interfacial transition zones (ITZ) decreased with an increase of BSA. The optimal percentage of BSA obtained was at 1.25%. The established model showed significant model terms (Sum of Squares = 260.60, F value = 69.84) with probability of 0.01% for the F-value to occur due to noise. The established model is useful for application in construction industries.

Concrete is a widely utilized construction material globally; however, it is characterized by a fundamental deficiency in its tensile strength when it is not reinforced. The incorporation of diverse novel materials into concrete is being pursued with the aim of mitigating its limitations while concurrently enhancing its reliability and sustainability. Furthermore, it is noteworthy that concrete embodies a significant quantity of carbon. The primary cause of this phenomenon can be attributed to the utilization of cement as the principal binding component in concrete. Recent advancements in research have indicated that jute fiber, commonly referred to as JF, exhibits considerable potential as a novel material for enhancing the mechanical robustness of concrete. Although there is a significant body of literature on the application of jute fiber in concrete, there has been a dearth of research on the capacity of jute fiber (JF) to improve the mechanical strength of concrete and mitigate its carbon emissions. This study aims to cover a gap in the existing literature by analyzing and enhancing the application of JF in relation to its mechanical properties and environmental impact. The study involved conducting experiments wherein JF was added at varying weight percentages, specifically at 0%, 0.10%, 0.25%, 0.50%, and 0.75%. The investigation encompassed a number of examinations of both the fresh and hardened states of concrete, in addition to assessments of its durability. The fresh concrete tests included the slump test, while the hardened concrete tests involved measuring compressive strength (CS), split tensile strength (STS), and flexural strength (FS). Additionally, the durability tests focused on water absorption (WA). The study involved the computation of embodied carbon (EC) ratios for various mix combinations. The findings suggest that incorporating JF into concrete results in a decrease in environmental impact relative to alternative fiber types, as demonstrated by a rise in eco-strength efficiency (ESE). Based on the findings of the conducted tests, an optimal proportion of 0.10% JF has been determined to be conducive to enhancing the CS, STS, and FS by 6.77%, 6.91%, and 9.63%, respectively. The aforementioned deduction can be inferred from the results of the examinations. Using data obtained from extensive experimentation, the RSM (Response Surface Methodology) was used to construct a model. The model was optimized, resulting in the establishment of definitive equations that can be used to evaluate the effects of incorporating JF into concrete. Potential benefits have been identified for the advancement of concrete in the future through the utilization of JF.

Increasing attention was given to building information modeling (BIM) and multi-criteria decision-making (MCDM) globally due to their advantages for various stages of the life cycle of a building. The aim of this paper is to improve practitioners' understanding of the process for BIM and MCDM adoption towards sustainable construction through energy efficiency. A questionnaire survey is being conducted for construction professionals and building industry experts in Malaysia. With expert survey data, a multi-criteria decision model using analytical network process (ANP) was built to identify key factors affecting sustainable building by reducing both embodied and operational energy and carbon emissions. Data from the survey was analysed using descriptive statistics. Model developed consisted of three clusters with a total of six nodes, and the level of importance was compared pairwise with one another. Results shows that design optimisation, reduced material requirements are important factors for sustainable construction considered in the BIM application.

This paper presents a case study on the implementation of the construction and demolition waste management practices in the Malaysian construction sector. The scope was limited to the housing and high-rise buildings. Characterization of reuse and recycling potential was done using descriptive statistics. It is estimated that the waste generated by the housing sector is approximately 16% of the gross materials used, which is about 8.8 million tons/year, and 32% of such waste (approximately 2.8 million tons/year) has the potential for reuse and recycling. However, the high-rise building construction generates construction waste in a large quantity of more than 10 million tons/years (about 70% of the building construction waste), which shows a high potential for reusability and recycling. The reasons behind the low recycling potential for the construction and demolition (C&D) waste generates by the housing sector are found that its quality is low and contains some types of contaminants.

The Internet of Things is a comprehensive system of connected computing devices and sensors that provide extensive data sharing capability for any specific purpose. For the construction industry, the applications of the Internet of Things have been increasing over the past few years, and it is because technology can provide full support to construction projects in attaining significant efficiency. The most critical part of construction products where the internet of things can be adopted is safety management because hundreds of accidents happen every year that result in significant injuries to construction workers and even death in some cases. For small construction projects, the situation is much worse, as there are never enough resources to adopt the latest technology, such as the Internet of Things. This study is structured with the aim of identifying the critical implementation barriers of the internet of things that affect small construction projects in Malaysia specifically. A mixed methodology study design is followed in which, after identifying the implementation barriers of the internet of things from existing literature, they are filtered with expert opinion. A pilot survey was conducted on which exploratory factor analysis was applied to further identify the significant barriers relating to the Internet of Things in small construction projects in Malaysia. A main survey was conducted afterwards, on which the structural equation modelling was done to develop the model involving the final 16 barriers divided into 5 formative constructs. The most critical barriers are found to be related to databases and technology, while the least impact is created by management barriers. Positive theoretical and managerial implications are indicated for future researchers and construction workers, respectively, by which they can improve the implementation of internet of things in small construction projects in Malaysia.

As a top construction material worldwide, concrete has core weakness relating to low tensile resistance without reinforcement. It is the reason that a variety of innovative materials are being used on concrete to overcome its weaknesses and make it more reliable and sustainable. Further, the embodied carbon of concrete is high because of cement being used as the integral binder. Latest research trends indicate significant potential for carbon fiber as an innovative material for improving concrete mechanical strength. Although significant literature is available on the use of carbon fiber in concrete, a limited number of studies have focused on the utilization of carbon fiber for concrete mechanical strength improvement and the reduction of embodied carbon. Following the gap in research, this study aimed to investigate and optimize the use of carbon fiber for its mechanical characteristics and embodied carbon improvements. The use of carbon fiber in self-compacting concrete lowers sagging. The greatest quantity of carbon fiber is that it reduces the blockage ratio, forcing the concrete to solidify as clumps develop. With time, carbon fiber improves the durability of concrete. Self-compacting concrete with no carbon fiber has a poor tensile strength. Experiments were conducted by adding carbon fiber at 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% by weight. Fresh concrete tests including slump test and L-box test, hardened concrete tests involving compressive strength and splitting tensile strength, and durability tests involving water absorption and acid attack test were conducted. Embodied carbon ratios were calculated for all of the mix ratios and decreasing impact, in the form of eco-strength efficiency, is observed with changes in the addition of carbon fiber in concrete. From the testing results, it is evident that 0.6% carbon fiber is the ideal proportion for increasing compressive strength and split tensile strength by 20.93% and 59%, respectively, over the control mix. Response Surface Methodology (RSM) is then applied to develop a model based on results of extensive experimentation. Optimization of the model is performed and final modelled equations are provided in terms of calculating the impact of addition of carbon fiber in concrete. Positive implications are devised for the development of concrete in the future involving carbon fiber.

Abstract Ensuring oil-well-integrity is one of the challenging tasks when cementing is designed. It has been well established that cement tends to degrade when exposed to a corrosive environment and at elevated temperatures. This paper presents the results of the uniaxial compressive strength of the qualified mixes of geopolymer cement containing fly ash as the precursor. Geopolymer cement samples were cured in the potable water heated at 60 °C and 90 °C for 24 h before testing for uniaxial compressive strength. Uniaxial confined compressive strength test was performed for samples cured at a 60 °C, and results of the samples bearing density of 13, 15, and 17 ppg were obtained as 4.12, 9.21 and 17.68 kPa, respectively. For 90 °C, the compressive strengths were 4.43, 15.34 and 78.14 kPa, respectively, for the samples bearing the same density. Samples cured at 90 °C showed the higher value of UCS as compared to the samples cured at 60 °C, and it was because heat is required to stimulate the polymeric reaction.

Wind-induced loads and motions play a critical role in designing tall buildings and their lateral structural systems. Building configuration represented by its outer shape is a key parameter in determining these loads and structural responses. However, contemporary architecture trends towards creating taller buildings with more complex geometrical shapes to offer unique designs that become a signature on the map of the world. As a result, evaluating wind-induced motions on such structures becomes more challenging to be evaluated and predicted. This paper presents a computational performance-based aerodynamic optimization with minor imposed modifications that have little to no impact on architectural and structural design intent. The developed tool aims to assist both architects and engineers to seek a sustainable optimal design decision at the early stage of design by employing different computational technological tools in an automated manner. A computational optimization methodology consisting of a computational fluid dynamic coupled with finite element analysis and embedded within a radial basis function surrogate model is proposed to mitigate wind-induced loads on tall buildings. In addition, a numerical example implementing the proposed methodology on selected case study is presented and discussed. The proposed approach was able to achieve a minimization of 13.83% and 23.12% for along-wind and across-wind loads, respectively, which is translated to a reduction in structural response by 12.95% and 14.31% in maximum deflection for along-wind and across-wind directions, respectively.

In selecting the binder composition for oil well application, its stability is an important design parameter. This paper presents the results of an experimental study conducted for comparing the linear expansion characteristics of geopolymer cement with the traditionally used ASTM Class G cement system. The expansion test was done in a water bath at 60 °C subjected to different curing intervals. The linear expansion of a cement system defines as the dimensional changes occur in the system, which is sometimes required to avoid the cement shrinkage during the hydration phase. In the case when the desired level of expansion is not achieved in the system, then the commercially available expandable materials are added in the class G cement system that enables the system to expand to the desired level. Shrinkage in the cementing system causes the formation of a microannulus or induces a gap that may allow the migration of fluid, hence the integrity of the system could be lost. This experimental study has revealed that the geopolymer cement tends to expand 0.15%–0.2% without the addition of any admixture, whereas the ASTM Class G cement has shown a lower value of linear expansion, which was obtained less than 0.1% after 18 days of curing. In the case of Class G cement, the addition of expandable material helped to increase the expansion; in the case of a geopolymer system, the additive has further accelerated the expansion.

The present study aimed to investigate the effect of an expandable additive on the compressive strength and linear expansion of geopolymer cement, which is an alternative to ordinary Portland cement, for oil-well cementing. Fly-ash-based geopolymer cement samples, with the addition of slag cement as a strength enhancer, were prepared by using an elastomeric expandable additive (R-additive), which consists of styrene–butadiene rubber with a specific gravity of 0.945, at concentrations of 10%, 15%, 20% and 25% by weight of the solid blend, and cured in a water bath at 60 °C and atmospheric pressure, and a curing chamber at 90 °C and 3000 psi, or approximately 20.68 MPa. Mixability, amount of free water and slurry density were studied, and the effects of the concentration of R-additive on the compressive strength (F) and linear expansion (∆l/l0) of the samples were analyzed. When cured at 60 °C and atmospheric pressure, the highest F of 15.01 MPa was obtained when the concentration of R-additive was 10%, while the highest ∆l/l0 of 0.9985% was obtained when the concentration of R-additive was 25%. An increase in the curing temperature and pressure to 90 °C and 3000 psi (≈20.68 MPa) resulted in the reduction of F from 15.01 to 14.62 MPa and from 10.33 to 9.61 MPa, and the increase in ∆l/l0 from 0.52% to 0.63%, and from 0.99% to 1.32%, when the concentrations of R-additive were 10% and 25%, respectively. The findings suggest that the formulations adopted, which contain R-additive at concentrations ranging from 10% to 25%, fulfilled the requirements of the oil and gas industry.

Silica aerogel possesses an ultra-low thermal conductivity by virtue of its nano-structure. Owing to the fragility of monolithic aerogel, the development and production of aerogel-based insulation materials involve the incorporation of granular aerogel with other materials to form composite materials. In the present study, the application of silica-aerogel-incorporated composite cement paste as render on the roof-top surface is coupled with the installation of a novel silica-aerogel-incorporated composite insulation board below the roof tiles. Control and silica-aerogel-incorporated samples of the composite cement paste and insulation were prepared. Thermal conductivity and strength tests were performed on the samples. A simulation study was performed on a Building Information Model subjected to a tropical climate to project the resultant impact of the cement render coupled with the insulation board on the thermal-energy-efficiency of the roof. For optimization of thermal and strength performances, silica aerogel contents of 4 wt.% and 3 wt.% were selected for the cement render and insulation board, respectively. The projected annual cooling load and energy savings revealed that the application of a 20-mm cement render, coupled with the installation of a 100-mm thick insulation board, is recommended as the optimum roof configuration.

This experimental study investigated the effects of polyvinyl alcohol (PVA) and copper-coated steel (CCS) on the mechanical properties and the post cracking behavior of fiber reinforced concrete (FRC). In designing high-performance concrete mixes, cement replacement materials are the essential ingredients. Therefore, the research objective was to investigate PVA and CCS fiber’s post-cracking performance in 100% cement concrete and concrete with 80% cement and 20% fly ash. The fiber content was fixed as a 0.3% volumetric fraction. CSS fibers required 15% more superplasticizer to achieve the desired slump of fresh concrete than the PVA fibers. Simultaneously, CCS fibers showed a 10% higher compressive strength than the concrete made of PVA fibers. Both fibers exhibited a similar effect in developing tensile and flexural strength. PVA fibers showed a value of 47 Gpa of secant modulus, and CCS fibers resulted in 37 Gpa in 100% cement concrete. In post-cracking behavior, CCS fibers showed better performance than the PVA fibers. The reason for this is that CCS showed 2.3 times the tensile strength of the PVA fibers. In comparing the two concretes, fly ash concrete showed about 10% higher compressive strength at 56 days and about 6% higher tensile and flexural strength. Similarly, fly ash concrete showed more than 15% first crack strength and flexural toughness than the 100% cement concrete in post-cracking behavior. Fiber-reinforced concrete containing PVA or CCS fibers showed enhanced post-cracking characteristics and its use could be preferred in structural applications.

This paper presents an experimental investigation on geopolymer cement formulations for enhancing oil-well integrity. Fresh slurry properties, mixability, density, free-water, and rheology were determined for possible field applications. The compressive strength and expansion characteristics were studied for the durability and integrity of the well system. Mix formulations complied with the requirements of API RP 10B-2. All formulations showed homogeneous mixability, rheological properties, the plastic viscosity (PV), and yield point (YP) were increased from 48 cP to 104 cP and 3.8 N/m2 12.4 N/m2, respectively, with the increase of the dosage of elastomeric type expandable material (R additive). The highest compressive strength of 15 MPa was obtained using 10% R additive in the mix-blend after 60 days of curing. Increasing the amount of R additive provides the optimum strength at 10.4 MPa with design 2, 3, and 4. The linear expansion was increased to about 1% at 60 days with 20% and 25% of the R additive dosage. Design of Experiment (DOE) was performed for setting three factors: curing time (A), curing temperature (B), and concentration of R additive (C) to optimize the linear expansion (response).

This paper presents the experimental analysis of the effects of simulated hydrocarbon fire exposure on the mechanical properties and the heat transmission in fiber-reinforced self-compacting concrete, FR-SCC. For that purpose, 300-mm thick, and 1200-mm square-shaped slabs were cast. Basalt and polyvinyl alcohol (PVA) fibers were added using the content of 1, 1.5, and 2% in self-compacting concrete. For investigating the heat transmission within 300-mm thick slabs, five external thermocouples were installed at the unexposed face to the fire of the slabs. Similarly, eleven internal thermocouples were installed at an interval of 25 mm throughout the slab thickness. It has been found that fibers have shown better insulation than the controlled concrete; the unexposed to fire surface of FR-SCC showed temperatures lower by ten degree Celcius than the controlled concrete. Compressive strength results showed that fiber addition caused a higher reduction in strength because of softening and stiffness reduction due to high-temperature exposure. After 120 min of fire exposure, basalt fibers caused an average reduction of 30% in the compressive strength, and PVA fibers caused an average reduction of 25%. Whereas, the addition of fibers improved the split cylindrical tensile strength even after exposure to 120 min of fire exposure in comparison with the unreinforced samples.

The concept of a sustainable environment generally refers to the development that creates a balance between the resources consumption pattern and the rate of depletion of natural resources. For determining the level of sustainability of any project, three types of impacts are assessed: economic, environmental, and social. This paper presents an analytical study that focused on establishing a correlation of eco-efficiency index for low-rise reinforced concrete residential housing in Malaysia. A statistical technique using the response surface method was performed, with the help of design expert software. The data was verified using regression analysis and represented by R2 value, standard deviation, and coefficient of variation. By using economic factors, environmental factors, and the eco-efficiency index, 3D model graphs were developed for structural concrete containing fly ash, and blast furnace slag (BFS), which was assigned to the structural members in a single and double story housing. The study has concluded that the correlations established between the cost and carbon emission, economic & environmental scores, and the eco-efficiency index have shown a linear trend for single story housing and a cubic for the double story housing.

Roller compacted concrete (RCC) pavement is subjected to continues traffic loading from vehicular activities which can results to fatigue cracking. Fatigue is one of the commonest defects affecting pavement which affect the cost of maintenance, and shortens pavement design life. To carter for these factors, higher deformation resistant pavements with longer design life need to be designed. Therefore, in this study, crumb rubber was used as a partial replacement to fine aggregate in RCC pavement to improve its fatigue life. Five mixtures were considered; one control mixture, two mixtures with fine aggregate replaced using crumb rubber at 10 and 20% by volume; one mixture containing 20% crumb rubber as partial replacement to fine aggregate 1% nano silica added by weight of cementitious materials. Lastly, one high volumefly ash (HVFA) RCC pavement mixture where 50% cement was replaced with fly ash, and 20% fine aggregate replaced with crumb rubber. The results showed that both crumb rubber and nano silica increases the bending resistance and fatigue life of RCC pavement. While HVFA decreases both flexural strength and fatigue performance of RCC pavement. The double logarithmic-equation can best be used to determine the stress level–number of cycles (S–N) fatigue behavior and relation for RCC pavement mixtures.

Roller compacted concrete (RCC) pavement usage is limited to low-speed roads due to its low skid resistance, caused by the smooth surface texture that makes it unsuitable for use in high-speed traffic pavements. If used in high-speed roadways will lead to increased skid related accidents. In this study, crumb rubber was used as partially replaced with fine aggregate at levels 10, 20, and 30% by volumeto produce roller compacted rubbercrete (RCR) so as to improve the skid resistance of RCC pavement, and nano silica was added at 0, 1, 2 and 3% by weight of cementitious materials to mitigate loss of strength with incorporation of crumb rubber. The British Pendulum Number (BPN) was used to measure the skid resistance. Incorporating up to 20% crumb rubber and 2% nano silica increases both skid and impact resistance. The findings showed that RCR with 20% CR and 2% NS can be used for motorways, trunk, and class 1 roads. Finally, response surface methodology was used to develop the relationship between BPN in wet/dry conditions and crumb rubber/nano-silica. The analysis of variance for response surface methodology analysis shows that the quadratic models developed has a very good degree of correlation, and can be used to predict the skid resistance of RCR. The results of multi-objective optimization showed that an optimum mixture can be achieved with a 17.20% volumereplacement of fine aggregate and 1.87% nano silica addition by weight of cementitious materials to have the highest skid resistance RCR for pavement applications.

There is a global outcry over the speedy deterioration of structures in oil and gas facilities. While marine environment is considered the leading factor in the deterioration of offshore structures, there is no single factor considered as the main cause of the problem in onshore structures. Therefore, the aim of this paper is to present the result of global survey on the major factors causing the deterioration of concrete structures in onshore oil and gas facilities. To realize the objectives of the paper, an e-questionnaire was administered through two International LinkedIn groups with a membership mainly dominated by experts in onshore oil and gas facilities. 159 respondents completed the questionnaires, and the reliability of the responses was calculated to be 0.950 which is considered excellent. Relative importance index was used in ranking the factors, and it was observed that environmental factors ranked as the dominant factors causing the deterioration of concrete structures in onshore process plants. Another important finding in the study is the role that experience plays on the perception of experts on the causes of defects on concrete structures.

A flexural capacity model for fibre-reinforced concrete (FRC) beams reinforced with PVA and basalt fibres is suggested for the rectangular beam sections. The proposed models are based on the concept of equivalent stress block parameters for both compressive and tensile stresses, similar to Eurocode and ACI code. The parameters are defined by allowing the conversion of the stress-strain models into equivalent rectangular stress blocks, similar to Eurocode 2. The flexural model is suggested to determine the loading capacity of 21 FRC beams containing up to 3% volume fraction of PVA and basalt fibres without reinforcing bars. In order to investigate the accuracy of the proposed flexure models, finite element analysis (FEA) of the same beams was carried out using the compressive and tensile stress-strain curves. Furthermore, 21 FRC beams subjected to three-point bending were tested. The results of the flexural models showed good agreement with the load-carrying capacity of the tested FRC beams, and the results of FEA of all beams showed a good correlation with the experimental results in terms of the maximum load, load versus midspan deflection patterns, and the maximum tensile strains.

This paper reports the results of the laboratory tests conducted to investigate the effect of sodium hydroxide concentration on the fresh properties and compressive strength of self-compacting geopolymer concrete (SCGC). The experiments were conducted by varying the concentration of sodium hydroxide from 8 M to 14 M. Test methods such as Slump flow, V-Funnel, L-box and J-Ring were used to assess the workability characteristics of SCGC. The test specimens were cured at 70°C for a period of 48 hours and then kept in room temperature until the day of testing. Compressive strength test was carried out at the ages of 1, 3, 7 and 28 days. Test results indicate that concentration variation of sodium hydroxide had least effect on the fresh properties of SCGC. With the increase in sodium hydroxide concentration, the workability of fresh concrete was slightly reduced; however, the corresponding compressive strength was increased. Concrete samples with sodium hydroxide concentration of 12 M produced maximum compressive strength.

Preserving airport pavement means guarantying the safety operation of aircraft movements. There are four aspects that cause progressive pavement deterioration, i.e. the construction design and process, selected material, and maintenance management. One of the traffic aspects, jet engine exhaust, has not been discovered yet. The load pattern of the jet exhaust follows the schedule of aircraft traffic. The assumption held in this research is that the thermal load during aircraft movement may generate a high temperature, which is induced into pavement layers. The objective of this research is to determine the temperature gradient in the pavement, caused by the jet exhaust. This paper discusses the process of determining the temperature gradient in four stages, i.e. by carrying out the gap analysis, evaluation of pavement structures, determination of the load path and the magnitude, and defining the temperature gradient. The temperature gradient in the pavement layer is determined through the development of a model of cyclic loading. The thermal cyclic load follows the aircraft schedule pattern. The pavement temperature receives the thermal cyclic load of the sinusoid of solar radiation. The results indicate that the temperature of the pavement is increased and pavement temperature rises by 35 °C. However, after 60 seconds the remaining temperature of the pavement layer decreases to the initial temperature, which is caused by solar radiation.

The mechanical properties of high-strength ductile concrete (HSDC) have been investigated using Metakaolin (MK) as the cement replacing material and PVA fibers. Total twenty-seven (27) mixes of concrete have been examined with varying content of MK and PVA fibers. It has been found that the coarser type PVA fibers provide strengths competitive to control or higher than control. Concrete with coarser type PVA fibers has also refined microstructure, but the microstructure has been undergone with the increase in aspect ratio of fibers. The microstructure of concrete with MK has also more refined and packing of material is much better with MK. PVA fibers not only give higher stiffness but also showed the deflection hardening response. Toughness Index of HSDC reflects the improvement in flexural toughness over the plain concrete and the maximum toughness indices have been observed with 10% MK and 2% volume fraction of PVA fibers.

This paper presents a review of the properties of fresh concrete including workability, heat of hydration, setting time, bleeding, and reactivity by using mineral admixtures fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK), and rice husk ash (RHA). Comparison of normal and high-strength concrete in which cement has been partially supplemented by mineral admixture has been considered. It has been concluded that mineral admixtures may be categorized into two groups: chemically active mineral admixtures and microfiller mineral admixtures. Chemically active mineral admixtures decrease workability and setting time of concrete but increase the heat of hydration and reactivity. On the other hand, microfiller mineral admixtures increase workability and setting time of concrete but decrease the heat of hydration and reactivity. In general, small particle size and higher specific surface area of mineral admixture are favourable to produce highly dense and impermeable concrete; however, they cause low workability and demand more water which may be offset by adding effective superplasticizer.

This paper presents the mechanical properties and the microstructure of the high performance fiber reinforced concrete (HPFRC) containing up to 3% volume fraction of chopped Basalt fibers. Three types of the concrete were prepared, out of which, the first type was prepared by utilizing 100% cement content. The other two types of the concrete were prepared by replacing 10% cement content with silica fume and the locally produced metakaolin. Using each concrete type, four mixes were prepared in which Basalt fibers were added in the range of 0–3%; that is, total twelve mixes of the HPFRC concrete were prepared. From each of the twelve concrete mixes, total twelve specimens were cast to determine the mechanical properties of the HPFRC including compressive strength (cube and cylinder), splitting tensile strength, and the flexural strength. In this way, a total of 108 specimens were cast and tested in this study. Test results showed that the addition of the Basalt fibers significantly increased the tensile splitting strength and the flexural strength of the HPFRC, while there was slight improvement in the compressive strength with the addition of Basalt fibers. The microstructure of HPFRC was examined to determine the interfacial transition zone (ITZ) between the aggregates and the paste by using field emission scanning electron microscope (FESEM), which showed the improvement of the ITZ due to the addition of the Basalt fibers.