Sustainable Ultra-high Performance Concrete Research Articles

Using Multiple Machine Learning Models to Predict the Strength of UHPC Mixes with Various FA Percentages

Ultra High-Performance Concrete (UHPC) has shown extraordinary performance in terms of strength and durability. However, having a cost-effective and sustainable UHPC mix design is a challenge in the construction sector. This study aims on building a predictable model that can help in determining the compressive strength of UHPC. The research focuses on applying multiple machine learning (ML) models and evaluating their performance in predicting the strength prediction of UHPC. Two reliable metrics are used to evaluate the performance of the model which are the coefficient of determination (R2) and mean squared error (MSE). The parameters that are affecting the compressive strength of UHPC are fly ash percentage levels (FA%), superplasticizer content, water to binder ratio (w/b), and curing period. A total of 54 ML models were used, consisting of Linear Regression, Support Vector Machines (SVM), Neural Networks, and Random forests algorithms. Among these models, Random Forest proved to be the most effective in capturing the relationships in UHPC’s behaviour with an R squared score of 0.8857. The Random Forest ML model is also used in this paper to conduct a parametric study that will help in obtaining the compressive strength of UHPC with higher content of FA%, which is not sufficiently studied in the literature.

Recycling lithium slag into eco-friendly ultra-high performance concrete: Hydration process, microstructure development, and environmental benefits

To ascertain the viability of utilizing lithium slag (LS) in the development of eco-friendly ultra-high performance concrete (UHPC), this paper provides a detailed analysis of the effects of LS on UHPC. Specifically, the hydration and microstructural changes in UHPC containing LS (LS-UHPC) were comprehensively examined. Based on the results of isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP), LS primarily acts as a filler, promotes nucleation, provides internal curing, and participates in the pozzolanic reaction. Significantly, the internal curing effect and the pozzolanic reaction enhanced the strength development of LS-UHPC. UHPC with 20 % LS exhibited the highest 28 d compressive strength at 134.48 MPa and presented the densest microstructure. However, approximately 4 % of the calcium hydroxide in LS-UHPC would not be involved in the pozzolanic reaction. The presence of gypsum in LS led to increased ettringite formation in LS-UHPC. Although LS extended the induction period of UHPC, it intensified the hydration degree of cement. In LS-UHPC, the molar ratio of Ca/Si of C-(A)-S-H decreased, whereas the molar ratio of Al/Si increased, implying that the dissolved aluminum from LS was incorporated into the C–S–H chains. The integration of LS not only considerably reduced the carbon emissions and energy consumption of UHPC but also optimized LS recycling. Overall, the development of a sustainable UHPC by incorporating LS is both practicable and advantageous for environmentally conscious construction practices.

Effect of industrial wastes on the properties of sustainable ultra-high-performance concrete: Ganite, ceramic, and glass

The creation of ultra-high-performance concrete (UHPC) requires a huge amount of cement. However, the production of cement raises environmental concerns related to non-renewable resources, carbon dioxide emissions, and global warming. To overcome these issues, it was necessary to expand the production of eco-friendly, sustainable ultra-high-performance concrete (SUHPC) by applying procedures to minimize cement use. This research was able to produce SUHPC with compressive strengths ranging from 168 to 233 MPa at 91 d under standard curing by employing industrial wastes such as granite dust, ceramic powder, and glass powder as a partial replacement of cement by about 26% of its weight, in addition to using crushed granite, ceramic, and glass as a 50% and 100% by volume substitute for sand within the concrete mixture. The influence of these industrial wastes on the mechanical and physical characteristics of SUHPC was investigated. Additionally, the temperature studies on the SUHPC containing industrial wastes and the analysis of the microstructure were presented. The study revealed that replacing some of the cement with granite powder and all of the sand with crushed granite in the SUHPC mixture led to the highest compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity. Specifically, the mixture achieved 196.7 MPa compressive strength, 21.9 MPa splitting tensile strength, 30.3 MPa flexural strength, and 61,010 MPa modulus of elasticity after 28 d. Furthermore, the replacement significantly improved the SUHPC's physical properties. For instance, it reduced water permeability by 18.83%. However, adding glass to the SUHPC mixture negatively impacted both its mechanical and physical characteristics.

Exploring the potential of agricultural waste as an additive in ultra-high-performance concrete for sustainable construction: A comprehensive review

Abstract This study thoroughly reviews the recent design methods for ultra-high-performance concrete (UHPC) with agricultural waste. The goal is to identify UHPC composites that meets environmental sustainability requirements while fulfilling workability, durability, and mechanical properties. The capacity of typical review studies is limited in bridging the various literature aspects systematically. The article includes comparative analyses identifying these methods’ intrinsic connections and current trends. The analysis indicates that 71% of documents on incorporating agricultural waste into UHPC are in the “Engineering” and “Materials Science” disciplines, with 69% being journal articles, and 27% conference documents. Significant research keywords involve “Ultra-High-Performance Concrete,” “Cements,” “Sustainable Development,” and “Agricultural Wastes,” highlighting the extensive exploration of agricultural waste in UHPC. It has been discovered that agricultural waste can replace silica fume in UHPC, improving strength and durability by reducing pore volume and enhancing microstructure. Substituting 5–30% of cement with rice husk ash significantly boosts compressive strength, enhancing cement hydration, pore structure, and pozzolanic reaction, offering substantial environmental benefits and supporting the construction industry’s contribution to low-carbon sustainable development. This article provides guidance and recommendations for developing sustainable UHPC to meet diverse design specifications, promoting environmentally friendly construction practices.

Mechanical Properties and Durability of Sustainable UHPC Using Industrial Waste Residues and Sea/Manufactured Sand

Abstract Considering the continuous development of sustainable development, energy saving, and emission reduction concepts, it is very important to reduce concrete’s cement content in order to improve its environmental impact. Using a reactive admixture to replace part of the cement in ultra-high-performance concrete (UHPC) can effectively improve the overall performance of the concrete and reduce carbon dioxide emissions, which is an important aspect of environmental protection. Here, industrial waste residue (fly ash and slag), sea sand (SS), and manufactured sand (MS) were used to produce UHPC under standard curing conditions to reduce the material cost and make it more environmentally friendly and sustainable. The effects of water–binder ratio, contents of cementitious materials, types of sands, and content of steel fibers on the mechanical performance of UHPC under standard curing were investigated experimentally. In addition, evaluations of the impermeability, chloride, and freeze-thaw resistance of various UHPCs produced were conducted by investigating the effects of various factors on the depth under hydraulic pressure and electric flux of UHPC, as well as the mass loss, relative dynamic modulus of elasticity, flexural strength, and compressive strength of UHPC specimens after freeze-thaw cycles. The obtained experimental results show that the SS-UHPC and MS-UHPC prepared by standard curing exhibit high strength, excellent impermeability, and chloride resistance. The frost-resistant grade of all groups of UHPCs prepared by standard curing was greater than F500 and had excellent freeze–thaw resistance, including those produced with local tap water or artificial seawater. The investigation presented in this paper could contribute to the production of new low-cost and environmentally friendly UHPCs and accelerate the application of UHPC in engineering structures.

Influence of graphene oxide in the hydration mechanism by reinforcing mechanical strength and microstructural Characterization of ultra-high-performance concrete (UHPC)

In the past few years, one of the most promising graphite-based nanomaterials in the construction industry has been Graphene Oxide (GO) due to its outstanding performance combined with cementitious composites. Introducing extensive Engineering Cementitious Materials (ECMs) improves Ultra-High-Performance Concrete (UHPC) mechanical, durability, and microstructural characteristics. Very few studies have been concentrated on cement pastes, mortars, and regular concrete, high strength concrete. Limited studies on UHPC with large volumes of ECMs done. The present investigation mainly focuses on improving the UHPC in fresh, mechanical, and microstructural behavior. Four mixes were prepared with GO (0.00%, 0.03%, 0.06%, and 0.1% by weight of cement) and a water-cement ratio of 0.20. Results indicated that the mix with 0.06% GO had a better outcome and improved the compressive, split tensile, and flexural strength compared with other test mixes. Microstructural analysis carries out using x-ray fluorescence (XRF), x-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-dispersive x-ray Spectroscopy (EDS), Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR), Fourier-Transform Raman Spectroscopy (FT-RAMAN) on 28 days UHPC mixes and quality of the concrete mixes analyzed with Ultrasonic Pulse Velocity (UVP) test. They developed and established the fundamental step toward the cost-effective, eco-friendly, sustainable UHPC.

Optimal design and characteristics of sustainable eco-friendly ultra-high-performance concrete

Sustainable eco-friendly ultra-high-performance concrete (UHPC) is a remarkable innovation in construction technology. This research aims to develop sustainable UHPC by incorporating various supplementary materials, including silica fume (SF), glass powder (GLP), fly ash (FA), limestone powder (LP), and granite powder (GrP), as partial replacements for cement and fine aggregate. To achieve this goal, a total of twenty-seven concrete mixtures were designed using response surface methodology (RSM) and tested in order to determine the optimal combination of these supplementary materials for enhancing the mechanical properties of UHPC. Mathematical models were constructed using analysis of variance (ANOVA) test. The results of the study suggest that it is indeed possible to produce sustainable UHPC with reduced CO2 emissions and improved mechanical properties by utilizing the suggested supplementary materials. In particular, the compressive and flexural strengths of the concrete significantly improved when high proportions of LP, SF and GLP, and low proportions of FA and GrP were used. Among the various mixtures tested, the mixture containing 12.5% SF, 15% FA, and 10% GLP as partial replacements of cement, along with 12.5% GrP and 50% LP as partial replacements of fine aggregate, exhibited the highest compressive and flexural strength at all curing ages, the compressive strength was 133, 175.8, 180.2 MPa at age 7, 28 and 90 days, respectively, meanwhile the flexural strength was 38.5 MPa at age 28 days. The SEM results revealed that the higher proportion of LP, FA, and GLP contributed to an enhanced concrete microstructure, further validating the positive impact of these supplementary materials on UHPC's mechanical properties.

Developing a Sustainable Ultrahigh-Performance Concrete Using Seawater and Sea Sand in Combination with Superfine Stainless Wires

Developing a Sustainable Ultrahigh-Performance Concrete Using Seawater and Sea Sand in Combination with Superfine Stainless Wires

Cementless ultra-high performance concrete (UHPC) using CaO-activated GGBFS and calcium formate as an accelerator

This study proposes an innovative approach to develop cementless ultra-high performance concrete (UHPC) by activating ground granulated blast furnace slag (GGBFS) without an alkaline-activating solution. To develop cementless UHPC, calcium oxide (CaO) (5% by weight) was used to activate GGBFS, and calcium formate (CF) was used as an accelerator at concentrations ranging from 0 to 6 wt%. The results showed that CF significantly improved the mechanical properties until 5 wt% and all the samples, including CF, exhibited a compressive strength of over 150 MPa. Uniaxial tensile tests revealed strain-hardening behavior, similar to typical cement-based UHPC. The addition of CF led to an increase in hydration products and pore size refinement, resulting in improved mechanical properties. The life cycle assessment results indicated that the developed UHPC mixture had nearly 70% lower CO2 emission than cement-based UHPC. The experimental results highlight the potential of this method for sustainable UHPC development.

Preparation of sustainable ultra-high performance concrete (UHPC) with ultra-fine glass powder as multi-dimensional substitute material

High cost and CO2 emissions are the issues that need to be addressed in the widespread application of UHPC. The application of mineral admixtures in UHPC has become a new development direction. Ultra-fine glass powders with median diameter d50 of 316 nm (named as nGP) and 5.33 μm (named as mGP) were fabricated to replace silica fume and blast furnace slag, respectively, to prepare eco-friendly UHPC. The outcomes of the study revealed that both nGP and mGP can significantly promote the hydration of UHPC pastes. The incorporation of ultra-fine GP increased the hydration products and improved the microstructure of UHPC due to its pore filling effect, nucleation effect and pozzolanic activity. The compressive strength of UHPC containing ultra-fine glass powders was larger than the reference ones and the optimal substitution rates of silica fume by nGP and blast furnace slag by mGP were 60% and 50%, respectively. Ultra-fine GP is feasible to be employed as multi-dimensional substitute material to produce low cost eco-friendly UHPC.

The very early-age behaviour of Ultra-High Performance Concrete containing ground granulated blast furnace slag

Ultra-High Performance Concrete (UHPC), despite being a relatively new kind of advanced cement-based material (featuring outstanding mechanical performance and excellent durability), has been deemed unsustainable due to its high cement content, thus increasing its carbon footprint. The large amounts of cement and silica fume (SF) can also raise both production costs and cracking risks due to the high early-age autogenous shrinkage. This paper addresses an innovative approach for developing a more sustainable UHPC involving an efficient application of ground granulated blast furnace slag (GGBS). Slags of two fineness levels are used, displaying a Blaine fineness of 420 m2/kg (SL1) and 700 m2/kg (SL2), respectively. These slags have been incorporated as volume replacements for 30% and 50% cement.The results analysis shows that it is indeed possible to produce SL2-based UHPC with a behavior similar to that of classical silica fume-based materials. The partial replacement of ordinary Portland cement (OPC) by 30% of GGBS (SL1 or SL2) improves workability, promotes the hydration reaction of cement and accelerates setting. In this case, the nucleation site effect of GGBS particles dominates; it seems to be directly correlated with the fineness of the slag used. Thus, the finer additions result in a significant acceleration of setting and hydration. The dilution effect is more sensitive at 50% of SL1 substitution. This prevailing effect delays the hydration reaction, prolongs setting times and decreases the peak of heat flow. In contrast however, this delay effect was not observed for the mixture containing 50% of SL2. Shrinkage measurements indicated that 30% of SL1 induces a slight reduction in early-age chemical and autogenous types of shrinkage. The most severe shrinkage is clearly found in mixtures incorporating 30% of SL2. This phenomenon may be due to the distribution of refined pores, which increases capillary tension. A more sustainable UHPC containing a high level of superfine slag (50%) with less autogenous shrinkage has been successfully produced.

Using a combination of industrial and agricultural wastes to manufacture sustainable ultra-high-performance concrete

Today, recycling and the use of eco-friendly construction supplies are major concerns for the environment. Concrete is frequently utilized in the engineering and construction sectors. In the past several decades, ultra-high performance concrete (UHPC), characterized by very high mechanical qualities, has emerged as one of the most popular types of concrete. Huge quantities of Ordinary Portland cement (OPC) are often utilized; this increases the price of UHPC, limits its widespread usage in structural applications, produces a substantial quantity of carbon dioxide, and uses a sizable amount of natural resources. It is recommended that other additives be used in lieu of OPC in concrete preparation and that recycled aggregates from a variety of sources be used in place of natural aggregates to make UHPC production more environmentally friendly and economically feasible. This study combines industrial and agricultural waste to create an affordable and sustainable UHPC. For example, glass particles (GP) as a manufacturing byproduct generated by glass waste (GW) are utilized as an alternative for fine aggregate "sand (S)" with substitution ratios of 0 %, 50 %, and 100 %, while wheat straw ash (WSA), as an agricultural byproduct, is utilized as an OPC substitute at varying substitution ratios 0 %, 10 %, 20 %, and 30 %. We conducted and analyzed experiments with 12 mixtures divided into three groups. Several factors are studied, including slump flow, mechanical characteristics, drying shrinkage, high temperature, and microstructural features. Based on the obtained outcomes, boosting the percentage of GP utilized to substitute the S made it more workable. In addition, replacing 20 % of the OPC with WSA and 0 % of the S with GP yielded the best results in terms of mechanical characteristics. Increasing the WSA replacement rate while fixing GP to S substitution level significantly reduced drying shrinkage values. Lastly, the compressive strength (fc) findings of UHPC structural components exposed to elevated temperatures up to 200 °C were enhanced using GP as a replacement for S. In brief, the results of this experimental investigation can contribute well to illustrating the effect of utilizing GP and WSA to manufacture sustainable ultra-high-performance concrete.

Influence of red mud on the engineering and microstructural properties of sustainable ultra-high performance concrete

This paper introduces a new application of industrial solid waste red mud to use as a cementitious material in the development of ultra-high performance concrete (UHPC) performances. In addition, utilization of red mud can reduce the environmental impact of red mud landfill. For gaining this aims, UHPC specimens were prepared with different contents of red mud and analyzed the effects of different RM contents on the fluidity, setting time, mechanical properties, durability, drying shrinkage and microstructure of the red mud-based UHPC. The results indicated that fluidity was reduced to 310 mm at 20% red mud level, but it still belongs to enormous fluidity, which is convenient for construction. In addition, it is worth noting that using red mud instead of cement can significantly shorten the setting time, providing a new method for applying the UHPC rapid-repairing process. Red mud-based UHPC mortar prepared with appropriate red mud instead of cement exhibits higher mechanical properties, better durability and reduced drying shrinkage of UHPC during curing. After curing for 28d, the highest compressive strength of UHPC samples containing 20% red mud was 129.5 MPa, the compressive strength of the UHPC samples' sulfate resistance was 136.6 MPa, and the drying shrinkage value was around 414 µm. Moreover, observed information from scanning electron microscopy (SEM) noted that red mud can fill the micro-cracks between particles of cementitious materials, make the structure more compact and form new hydrates. Finally, the two characteristics of low cost and energy consumption further promote the sustainable application of red mud-based UHPC. Therefore, replacing OPC with 20% RM is meaningful to produce a sustainable UHPC mixture and field applications.

Analysis of Mechanical and Environmental Effects of Utilizing Waste Glass for the Creation of Sustainable Ultra-High Performance Concrete

Analysis of Mechanical and Environmental Effects of Utilizing Waste Glass for the Creation of Sustainable Ultra-High Performance Concrete

Effect of hybrid industrial and recycled steel fibres on static and dynamic mechanical properties of ultra-high performance concrete

Employing recycled tyre steel (RTS) fibres to replace industrial steel (IS) fibres in ultra-high performance concrete (UHPC) can improve its cost-effectiveness and sustainability. However, the lack of research on dynamic properties of such sustainable UHPC would hinder its application in concrete structures such as protective and defence structures which may experience different dynamic loadings. This paper experimentally investigates the effect of various RTS fibre replacement levels (0.5–2.0% by volume) on the flowability and quasi-static compressive, flexural and tensile strengths of UHPC as well as the dynamic splitting tensile behaviour under various strain rates (4.5–6.5 s−1). The conventional UHPC with 2.0% IS fibre was prepared as the reference. Results indicate that the flowability of UHPC containing RTS fibres is about 5–11% higher than that of reference UHPC. Rising the RTS fibre replacement level up to 1.0% increases the compressive, flexural and tensile strengths while after which, the strengths drop. The dynamic splitting tensile behaviour of all UHPC specimens is sensitive to strain rate in terms of failure pattern, dynamic splitting tensile strength, dynamic increase factor and energy absorption capacity. Using 0.5% RTS fibre to substitute IS fibre can bring the best synergy, leading to the highest dynamic splitting tensile properties of UHPC at a strain rate of approximately 4.5–6.5 s−1. The material cost, embodied carbon and embodied energy of UHPC are reduced by 9–57% in the presence of RTS fibres. The optimal RTS fibre replacement dosage for UHPC is 0.5% considering static mechanical properties, dynamic splitting tensile behaviour, material cost and environmental impact.

Investigation of the Physical Mechanical Properties and Durability of Sustainable Ultra-High Performance Concrete with Recycled Waste Glass

Construction material sustainability and waste reuse have emerged as significant environmental issues. Concrete is widely used in the building and engineering fields. Ultra-high performance concrete (UHPC), which has remarkably high mechanical properties, has become one of the most common concrete varieties in recent years. As a result, substantial amounts of Portland cement (PC) are frequently used, raising the initial cost of UHPC and restricting its broad use in structural applications. A significant amount of CO2 is produced and a large amount of natural resources are consumed in its production. To make UHPC production more eco-friendly and economically viable, it is advised that the PC in concrete preparations be replaced with different additives and that the recycled aggregates from various sources be substituted for natural aggregates. This research aims to develop an environmentally friendly and cost-effective UHPC by using glass waste (GW) of various sizes as an alternative to PC with replacement ratios of 0%, 10%, 20%, 30%, 40%, and 50% utilizing glass powder (GP). Fine aggregate “sand (S)” is also replaced by glass particles (G) with replacement ratios of 0%, 50%, and 100%. To accomplish this, 18 mixes, separated into three groups, are made and examined experimentally. Slump flow, mechanical properties, water permeability, and microstructural characteristics are all studied. According to the results, increasing the S replacement ratio with G improved workability. Furthermore, the ideal replacement ratios for replacing PC with GP and S with G to achieve high mechanical properties were 20% and 0%, respectively. Increasing the replacement rate of GP in place of PC at a fixed ratio of G to S resulted in a significant decrease in water permeability values. Finally, a microstructural analysis confirms the experimental findings. In addition, PC100-S100 was the best mix compared to PC100-S50 G50 and PC100-G100.

Innovative Ultra-High Performance Concrete (UHPC) Incorporating oil ash and electric arc furnace dust

Extensive modern industrialization produces massive amounts of hazardous waste, which becomes an enormous concern due to their harmful impacts on human health and the ecosystem. Tackling hazardous waste with a more secure approach is crucial. The use of hazardous wastes as building materials makes a significant contribution to environmental protection and supports sustainable growth in the construction industry. This study aims to develop eco-friendly innovative ultra-high-performance concrete (UHPC) comprising regionally accessible industrial waste materials such as oil ash (OA) and electric arc furnace dust (EAFD) as a partial replacement of micro silica (MS) and natural fine sand to minimize its environmental impact and reduce the amount of these wastes dumped in lakes and landfills, as well as diminishing the cost of UHPC. A total of 13 various UHPC mixes with varying replacements of MS and fine sand by OA and EAFD, e.g., 0 %, 5 %, 10 % and 20 % of the total mass of MS and fine sand, were made. The UHPC with 0 % replacement was maintained as a reference. The mechanical characteristics were investigated through compressive and flexural strength of the specimens. The ductile performance was examined through load-deflection, energy absorption capabilities, and fracture toughness. Lastly, the durability characteristics such as water absorption, water permeability, drying shrinkage, chloride penetrability, electrical resistivity and sulfate resistance was also examined. The outcomes demonstrated that 20 % OA and 5 % EAFD replacement of MS were the optimum levels of replacement that could produce sustainable UHPC with comparable mechanical and durability performance over the reference UHPC.

RETRACTED: Influence of eco-friendly fine aggregate on macroscopic properties, microstructure and durability of ultra-high performance concrete: A review

Ultra-high performance concrete (UHPC) is considered one of the promising future building material due to its excellent performance. However, it is important to note that the production of quartz sand, the fine aggregate of traditional UHPC, causes several environmental issues, including dust and noise pollution. In addition, excessive use of river sand as a raw material causes a sharp decrease in reserves. Thus, using river sand to prepare UHPC is not a sustainable method. Considering all these undesired impacts, it becomes a necessity for UHPC to meet the increasing demands of environmental sustainability. Another major issue confronting the world is waste disposal. Numerous studies show the feasibility of using industrial by-products, municipal solid waste, and recycled materials as fine aggregates for UHPC. The current work focuses on developing environmentally friendly UHPC using waste instead of quartz sand or river sand. The macroscopic (workability, compressive strength, flexural strength, elastic modulus and shrinkage), microstructural (pore structure, interfacial transition zone), and durability properties of eco-friendly UHPC were comprehensively reviewed. This paper aims to promote the utilization of waste to produce sustainable UHPC and the large-scale use of UHPC worldwide. This development will significantly reduce waste in landfill and decrease the environmental burden of conventional UHPC.

Mechanical and durability performance of ultra-high-performance concrete incorporating SCMs

Production of ultra-high performance concrete (UHPC) requires a high volume of micro silica (MS), called silica fume, that accounts for around 20% to 40% by weight of cement. Using large quantity of MS can impede the use of UHPC in the market due to its high cost and limited resources. This paper evaluates the possibility of producing sustainable UHPC utilizing Supplementary cementitious materials (SCMs) such as Metakaolin (MK), Fly Ash (FA) and Natural Pozzolan (NP) as a partial replacement of MS. The mechanical characteristics such as compressive strength, flexural strength, and fracture toughness and durability performance such as chloride penetrability, water permeability, drying shrinkage, water absorption, electrical resistivity and sulfate resistance were investigated. The results exhibited that a partial replacement of MS with 60% NP, 60% FA and 40% of MK contributed the paramount UHPC mixtures, with satisfactory strength and flowability requirements. The outcomes indicate that the increase in ultra-fine dosages decreases the flowability and increases the strength, as the finer particles perform as a filler between the cement and coarser grains. The UHPC specimens containing FA provided the worthiest results in comparison to other specimens. This study outcome also indicated that the SCMs can be used to develop UHPC with significant improvements in the mechanical and durability performance in comparison with conventional UHPC.

Recent trends in ultra-high performance concrete (UHPC): Current status, challenges, and future prospects

• UHPC is promptly developing as a leading concrete material for construction industries. • UHPC has exceptional properties, making it a potential functional solution for a sustainable construction. • This article scientifically reviews the carbon capturing, challenges, limitations, and applications of UHPC. • The findings of this review likely to help specialists in establishing the design guidelines for sustainable UHPC. • Further efforts are required to standardize testing characterization for the materials used in UHPC. Ultra-high performance concrete (UHPC) combines advanced fibrous and cementitious material technologies to achieve high strength and exceptional durability. The material tends to have microscopic pores that prevent harmful substances such as water, gas, and chlorides from entering. UHPC can also achieve compressive strengths above 200 MPa and tensile strengths above 20 MPa. It also shows significant tensile strain hardening and softening behavior. Owing to all these characteristics, UHPC has excellent performance, making it a potentially attractive solution for improving the sustainability of construction components. Despite UHPC’s outstanding mechanical properties, superior toughness and ductility, and extraordinary durability, various challenges prevent its widespread use. At the same time, several challenges are currently being faced in the applications of UHPC, which include i) design aspects such as material properties; ii) production technology for large-volume and/or long-span elements with low workability, high spalling, and high shrinkage strains; and iii) unknown durability characteristics after the appearance of long-term concrete cracking. With a lack of industry experience, UHPC specialists face additional challenges in spreading hands-on practice to concrete industry professionals so that the latter can be well versed in applying this sophisticated concrete technology. For these reasons, a comprehensive literature study on recent development trends of UHPC should be conducted to determine its current status and prospects. This article scientifically reviews the current status, carbon capturing capabilities, sustainability aspects, challenges and limitations, and potential applications of UHPC. This state-of-the-art review is aimed at helping scientific researchers, designers, and practitioners widen the use of UHPCs in advanced infrastructure applications. This review will help specialists to develop the design guidelines to enable the widespread application of sustainable UHPC. In doing so, design engineers will be provided with an assurance to fully exploit the high strength and other special properties of UHPC and develop models that can efficaciously estimate the ultimate bearing capacity of UHPC sections under various loading conditions.