High Performance Concrete Research Articles

Influence of Glass Microfibers on the Control of Autogenous Shrinkage in Very High Strength Self-Compacting Concretes (VHSSCC)

High-performance concrete (HPC) is widely used in infrastructure for its durability and sustainability benefits. However, it faces challenges like autogenous shrinkage, leading to potential cracking and reduced durability. Fiber reinforcement offers a solution by mitigating shrinkage-induced stresses and enhancing concrete durability. In this sense, this study investigates the use of glass microfibers to mitigate autogenous shrinkage and early-age cracking in high-strength self-compacting concrete. Samples were prepared with two water-to-binder ratios (w/b): 0.25 and 0.32; and three glass microfiber contents: 0.20%, 0.25%, and 0.30 vol.%. The concrete mixtures were characterized in the fresh state for slump flow and in the hardened state for compressive strength, static, and dynamic Young’s modulus. Unrestrained and restrained shrinkage tests were also conducted in the seven days-age. The findings revealed that glass microfibers reduced the workability in mixtures with lower slump flow values (w/b of 0.25), while less viscous mixtures (w/b of 0.32) exhibited a slight improvement. Compressive strength showed a proportional enhancement with increasing fiber contents in concretes with a w/b ratio of 0.32. A contrasting trend emerged in concretes with a w/b ratio of 0.25, wherein strength diminished as fiber additions increased. The modulus of elasticity improved with fiber additions only in the matrix with a w/b ratio of 0.25, showing no correlation with compressive strength results. In shrinkage tests, the addition of glass microfibers up to specific limits (0.20% for a w/b ratio of 0.25 and 0.25% for w/b of 0.32) demonstrated improvements in controlling concrete deformation in unrestrained shrinkage analyses. Concerning cracking reduction in restrained concrete specimens, the mixtures did not exhibit significant improvements in crack prevention.

Glass Fibre Reinforced Concrete (GFRC) Materials and Its Applications

In the 1940’s, potential of glass as a construction material was realized and improvement continued with the addition of zirconium dioxide in 1960's for harsh alkali conditions. The development of new glass fibre generations is focused on improving the process of material durability. In order to meet various needs, glass fibre reinforced concrete, or GFRC, was thus introduced into production. Research and experiments conducted on GFRC have demonstrated that the material quality and production precision have an impact on the material's mechanical and physical characteristics. GFRC can be applied anywhere an impermeable, weather-resistant, fire-resistant, light-weight, and robust material is required. With the development of technology, it may be possible to construct sophisticated freeform structures and entire buildings at a reasonable cost. Recently, research has been done on the impact of glass fibres in hybrid mixtures for high-performance concrete (HPC), a newly developed technology that is gaining popularity in the building sector.

Hyper ensembled extreme gradient boosting techniques via novel triple algorithms to appraise the hardened properties of modern ternary admixed concrete

Mechanical parameters used in many design codes can be achieved by expensive and time-consuming experiments or by non-destructive approaches such as estimative modelling. This investigation proposed Extreme Gradient Boost (XGB) for estimating the slump (SL) and compressive strength (CS) of high-performance concrete (HPC). In addition, to bring the results of the models closer to the experimental data and increase the accuracy, algorithms were combined with the model, including Sunflower Optimizer (SFO) and Jellyfish Search Optimize (JSO). The relevant models have been examined in three frameworks: individual, hybrid, and ensemble-hybrid. For this purpose, several evaluators were provided to determine the errors, compare, and accuracy of the presented models. The XGFJ model has demonstrated exceptional performance, achieving remarkable results in terms of RMSE (Root Mean Square Error) and R2 (R-squared) values. Specifically, it has attained an exceptionally small RMSE value of 1.785 for CS and 5.183 for SL, indicating the model’s high precision in predicting these parameters. Additionally, it has achieved the biggest R2 values of 0.9960 for CS and 0.9949 for SL. Additionally, it is worth noting that the XGSF model closely matches the performance of the ensemble form of XGFJ, as evident from its R2 values of 0.9956 for CS and 0.9934 for SL. Based on the study, it was observed that using machine learning to anticipate the mechanical characteristics of concrete is valuable and efficient and can be considered an alternative method instead of time-consuming laboratory methods. This research addresses challenges in predicting HPC properties fueled by the need to overcome drawbacks in traditional methods. Costly and time-intensive laboratory experiments prompted the exploration of alternatives, leading to the proposal of XGB combined with optimization algorithms (SFO and JSO). The study aims to enhance prediction accuracy while tackling broader concerns such as construction costs, material efficiency, and environmental impact. The resource-intensive nature of conventional methods, along with inaccuracies due to material variations, serves as a primary challenge. The proposed resolution advocates for a paradigm shift to machine learning, exemplified by the XGFJ model, showcasing exceptional precision and efficiency in predicting HPC properties.

Effect of Na2CO3 Replacement Quantity and Activator Modulus on Static Mechanical and Environmental Behaviours of Alkali-Activated-Strain-Hardening-Ultra-High-Performance Concrete

The application of alkali-activated concrete (AAC) shows promise in reducing carbon emissions within the construction industry. However, the pursuit of enhanced performance of AAC has led to a notable increase in carbon emissions, with alkali activators identified as the primary contributors. In an effort to mitigate carbon emissions, this study introduces Na2CO3 as a supplementary activator, partially replacing sodium silicate. The objective is to develop a low-carbon alkali-activated-strain-hardening-ultra-high-performance concrete (ASUHPC). The experimental investigation explores the impact of varying levels of Na2CO3 replacement quantity (0, 0.75 Na2O%, and 1.5 Na2O%) and activator modulus (1.35, 1.5, and 1.65) on the fresh and hardened properties of ASUHPC. The augmentation of Na2CO3 replacement quantity and activator modulus are observed to extend the setting time of the paste, indicating an increase in the modulus of the activator and Na2CO3 replacement quantity would delay the setting time. While the use of Na2CO3 intensifies clustering in the fresh paste, it optimizes particle grading, resulting in higher compressive strength of ASUHPC. The tensile crack width of ASUHPC conforms to the Weibull distribution. ASUHPC with a Na2CO3 replacement quantity of 0.75 Na2O% exhibits superior crack control capabilities, maintaining a mean crack width during tension below 65.78 μm. The tensile properties of ASUHPC exhibit improvement with increasing Na2CO3 replacement quantity and activator modulus, achieving a tensile strength exceeding 9 MPa; otherwise, increasing the activator modulus to 1.5 improves the deformation capacity, reaching 8.58%. Moreover, it is observed that incorporating Na2CO3 as a supplementary activator reduces the carbon emissions of ASUHPC. After considering the tensile performance indicators, increasing the activator modulus can significantly improve environmental performance. The outcomes of this study establish a theoretical foundation for the design of low-carbon, high-performance-alkali-activated-strain-hardening-ultra—high-performance concrete.

Metaheuristic optimization of machine learning models for strength prediction of high-performance self-compacting alkali-activated slag concrete

Metaheuristic optimization of machine learning models for strength prediction of high-performance self-compacting alkali-activated slag concrete

Effect of Cement Dosing Without Additions (CPA) on High-Performance and Ordinary Concrete Based Glass Powder as Fine Partial Cement Replacement - A Comparative Study

Abstract The main objective of this paper research is a comparative study on the effect of the glass powder (GP) substitute from collected and recycled glass waste, as a fine partial cement replacement on the mechanical performance and durability of high performance concrete (HPC) and ordinary concrete (OC). For this two cement dosing were used of 400 kg/m3 to formulate OC and 450 kg/m3 to formulate HPC, and GP as considered binder like cement and not as fine addition, hence binder represent the sum of cement with GP (L=C+GP) with which will be made our two concretes formulation. Two ratios were used for the Water/Binder (W/B), the first W/B=0.35 for the HPC and the second W/B=0.5 for the OC, this ration is very important to fix the concentration of superplasticizer. A percentage of 10% and 20% substitution of cement CPA without additions noted CEM I 52.5 by the glass powder with fineness of 3600 cm 2/g are used. The evaluation of the compressive strength was followed from 7 to 365 days in order to study the behavior of the GP at different ages affected by the cement dosing and the ratio W/B compared to the reference concrete without GP for the two concretes HPC and OC. At 28 days the strengths of concretes with GP is affected by the replacement of a quantity of cement since the two reference concretes were superior but beyond this age an inverse behavior is noticed such that results obtained at age of 365 days seem to be advantageous in terms of savings in the quantity of cement used by interpreting the compressive strength, and the decrease in quantity of water in the mixtures offers a remarkable difference between the two concretes studied by using 20 % of GP as replacement of cement.

Comparing conventional concrete to high performance concrete through life cycle assessment

Comparing conventional concrete to high performance concrete through life cycle assessment

Effect of Non-Class Fly Ash on Strength Properties of Concrete

Developing of green construction and reducing CO2emissions in the environment is a priority for industry in the coming years. Recycling fly ash in the concrete industry is a well-known way to reduce environmental impact. Aside from this benefit, there are numerous other positive effects of incorporating fly ash into concrete; however, in this research, the objective is to replace cement with a different percentage of non-class fly ash with high CaO, more than 42%. The analyzed variables are non-class fly ash properties, the effect of fly ash presence on the main properties of concrete and examining the optimum of non-class fly ash in ordinary concrete C-25/30 and high-performance concrete C-50/60. All investigations took place in the laboratory by producing 24 different mix designs and more than 1000 specimens to examine: consistency, setting time, shrinkage, and compressive strength in the short and long terms of curing. Recycling industrial waste in new construction, especially fly ash because of its non-uniform properties, still has some obstacles and is not a practical issue, but the future must be environmentally friendly, and this research proves that the objective of producing sustainable ordinary and high-performance concrete was achieved by replacing 40% of cement with non-class high CaO content fly ash. Doi: 10.28991/CEJ-2024-010-03-02 Full Text: PDF

Disperzivno armirani beton: korelacije između sastava, strukture i svojstava

This study focuses on the influence of metal fibres on the physical and mechanical properties of dispersed reinforced concrete with additions. The final aim is to design and obtain high-performance concrete. Mechanical strength is not always the primary requisite imposed on high-quality concrete. However, the durability provided by very low permeability and aggressive environment resistance can lead to high-performance concrete. Fly ash, granulated blast-furnace slag, and microsilica were used for concrete preparation, and metal fibres were used for disperse reinforcement. The effects of these additions and the presence of steel fibres are used to increase concrete ductility, its ability to absorb energy (to increase mechanical strength), and the improvement of general durability.

Cracking performance in the hogging moment region of HSS-UHPC continuous composite girder bridges

To elucidate the cracking performance of concrete slabs at the negative bending moment region of high strength steel (HSS)-ultra high performance concrete (UHPC) continuous composite girder bridges, eight scale-reduced steel-concrete composite beams, constructed using HSS and UHPC that varying parameters of UHPC slab thickness and width and shear connection degree at the steel-concrete interface were prepared and tested. The composite beams' cracking pattern, bending stiffness, load-deflection curve, steel-concrete interfacial slippage, and strain history were presented and discussed. The test results show that the HSS-UHPC composite beams subjected to negative bending moments exhibited favorable cracking performance. With the UHPC slab width increasing from 450 mm to 550 mm, the composite beams' initial cracking moment, bending stiffness, and flexural ductility increased by 33.4%, 20.5%, and 39.8%, respectively. The utilization of a thick UHPC slab benefited the performance of the composite beams under negative bending moments. Replacing the 80 mm-thick slab with a 110 mm-thick slab improved the structure’s cracking moment and bending stiffness by 15.0% and 21.4%, respectively. Additionally, as the shear connection degree increases from 0.64 to 1.02, the initial cracking and ultimate failure moments of the composite beam were improved by 7.2% and 1.6%, respectively. In contrast, the bending stiffness of the beams with a shear connection degree of 1.02 was 12.4% smaller than those of 0.64. A comprehensive comparison between the formula-predicted cracking performance and current experimental results was performed to examine the capability of existing design approaches in calculating the HSS-UHPC composite beams. The flexural resistance algorithm proffered by Xu exhibits favorable alignment with test results, thereby providing a compelling methodology for designing HSS-UHPC continuous composite girder bridges.

Investigation of the Workability, Strength, and Durability of Fiber-Reinforced High-Performance Concrete with Full Aeolian Sand

Investigation of the Workability, Strength, and Durability of Fiber-Reinforced High-Performance Concrete with Full Aeolian Sand

English

English

Enhancing high-performance concrete sustainability: integration of waste tire rubber for innovation

This study extensively explored the impact of integrating waste tire rubber into high-performance concrete (HPC) by substituting natural sand. Different fractions of rubber particles—5%, 10%, and 15% replacements of the fine aggregate—were rigorously investigated. Properties from fresh to hardened concrete were assessed, including compressive and tensile strength, modulus of elasticity, workability, and damping coefficient. Replacing up to 10% of sand with 0.6 mm rubber particles showed minimal strength compromise compared to standard HPC. However, at a 15% replacement rate, a noticeable decline in strength became evident, highlighting an optimal threshold for inclusion. Additionally, rubber incorporation notably enhanced concrete ductility and damping, marking a substantial improvement in dynamic properties. Efforts to offset strength reduction through increased fines content and mineral admixture could not counteract the decline at the 15% replacement level, suggesting limitations in compensatory measures. Methodological refinements enhanced data accuracy, including capping and surface treatments during compression testing. The study underlined the viability of controlled rubber substitution for bolstering HPC's dynamic attributes. Despite strength reductions at higher replacement rates, controlled waste tire rubber integration proves promising for enhancing HPC's dynamics without compromising structural integrity, advocating its suitability across diverse construction applications.

Experimental Study and Bearing Capacity Calculation of Compression-Reinforced Concrete Columns Strengthened with Ultra-High-Performance Concrete

A total of five ultra-high-performance concrete (UHPC)-strengthened reinforced concrete (RC) columns and one RC column were built and subjected to eccentric compression testing to examine the force performance of UHPC-strengthened eccentrically compressed plain RC columns. This experimental study examined the crack progression, the damage morphology, the deformation ability, the maximum load-carrying capacity, and the ductile properties of the eccentrically compressed columns. It also investigated the impacts of eccentricity, the reinforcement thickness, and the addition of steel fibers on the effectiveness of reinforcement. The cracking load, peak load, and ductility coefficient of the UHPC-reinforced specimens were increased by 100.28%, 172.30%, and 56.30%, respectively, compared with the RC column at an initial eccentricity of 50 mm. As the eccentricity distance increased, the bearing capacity of the UHPC eccentrically compressed specimens decreased, and the deformation capacity increased. Increasing the steel fiber dosage within the appropriate range decreased the crack width of the specimen. The addition of 2% steel fiber resulted in a 24.8% increase in cracking load, an 8.96% increase in peak load, and a 2.60% increase in ductility coefficient compared to the addition of 1% steel fiber. However, the reinforcing effect of UHPC was weakened under high eccentric pressures. Based on the theory of concrete structure and mechanical principles, the formula for calculating the compressive bearing capacity of RC columns strengthened with high-performance concrete was proposed. The results of calculating the positive section bearing capacity of eccentrically compressed RC columns reinforced with high-performance concrete are in good agreement with the test values. The results of this paper provide an experimental basis and theoretical foundation for the cross-sectional design of UHPC eccentrically compressed columns.

Research on uniaxial mechanical performance of high-performance concrete after high temperature rapid cooling and damage mechanism analysis

High-performance concrete (HPC) is widely used in civil and hydraulic engineering, with durability as its main indicator. During the service life of high-performance concrete structures, there is a risk of extreme fire incidents. The fire department generally adopt water cooling to quickly control the fire after a fire occurred. Studying the mechanical property of high-performance concrete after high temperature and rapid cooling is of great significance for evaluating the safety performance of high-performance concrete structures after a fire. Therefore, three types of uniaxial loading modes (uniaxial compression, pure shear, uniaxial tension) and five temperatures (20OC, 200OC, 400OC, 600OC, 800OC) were considered in this study. Hydraulic servo machine was used to conduct experimental research on the uniaxial mechanical properties of high-performance concrete after high temperature and rapid cooling. In addition, digital image correlation (DIC) and acoustic emission technology (AE) were combined to analyze the external and internal damage evolution processes of concrete during loading process. The experimental results are as follows: as the temperature increases, the compression strength of high-performance concrete under uniaxial compression is initially increased and then decreased, with a maximum reduction of 62.02%; however, the strength of high-performance concrete under pure shear and uniaxial tension conditions are gradually decreased, with maximum reduction of 76.12% and 81.26% respectively; compared to room temperature cooling conditions, the strength of high-performance concrete under water cooling condition is decreased more greatly, but this difference gradually decreases with the increase of temperature; combined with the analysis of DIC and AE, under different stress states, the surface main cracks of HPC become more tortuous and accompanied by more micro-cracks under the influence of high temperature, and the evolution process of cracks inside HPC also changes significantly with the temperature. At the same time, the surface damage process of HPC under the influence of load has obvious lag compared with the internal damage process. Finally, based on the cumulative ringing count obtained by AE, the damage process of high-performance concrete under different loads is characterized, and the constitutive model of high-performance concrete after high temperature and rapid cooling under different loading modes is established. The research results provide a theoretical basis for the safety evaluation and calculation of high-performance concrete structures after fire.

Improving Corrosion Resistance and Prolonging the Service Life of High-performance Concrete Structures Using Fly Ash and Ground Granulated Blast-furnace Slag

This study investigates the impact of ground granulate blast-furnace slag (GGBFS) and fly ash (FA) on both the corrosion resistance of steel reinforcement, assessed through the accelerated macrocell corrosion test (AMCT), and the durability characteristics of high-performance concrete (HPC). Additionally, the study encompasses an analysis of various concrete properties, including the pH of fresh concrete mixtures as well as water absorption, chloride permeability, and surface resistivity (SR) in hardened concrete specimens. Microstructure analysis on HPC specimens as well as the service life prediction of RCS were also performed in this study. Test results show that the HPC incorporating 35% GGBFS or 35% GGBFS + 20% FA as cement replacement resulted in a lowered pH of fresh mixtures while water absorption and chloride permeability of these specimens increased significantly. In addition, the incorporation of 35% GGBFS or 35% GGBFS + 20% FA concurrently enhanced the SR of HPC specimens. Moreover, these HPC specimens exhibited better corrosion resistance ability as their respective AMCT values were about 1.54 and 1.45 times higher than that of the control specimen. Further, the research highlighted a substantial extension in the corrosion initiation time of concrete structures employing 35% GGBFS or 35% GGBFS + 20% FA, about 3 and 6 times longer than the HPC without GGBFA and FA, respectively. The experimental results, confirmed by the substantial microstructural enhancement in the HPC containing GGBFS and FA, also demonstrated a close interplay between durability and other concrete properties such as water absorption, chloride permeability, and SR.

Application of High-performance Concrete in Civil Engineering

With the continuous improvement of modern civil engineering performance requirements on building materials, high-performance concrete (High-Performance Concrete, HPC) has become one of the key materials. This paper discusses the application of HPC in various civil engineering, and its innovative impact. HPC has played a key role in many major engineering projects for its extraordinary durability, high intensity and excellent working nature. First, the paper introduces the basic composition and performance characteristics of HPC, including its compressive strength, durability and rheological properties. The optimized formulation of HPC reduces the use of cement, and cement production is one of the major sources of carbon emissions. By using fly ash, silicon ash and other industrial by-products to replace part of the cement components, HPC not only improves its environmental friendliness, but also enhances the comprehensive performance of the material. Finally, the paper prospects the potential development of HPC in future civil engineering. With technological advances and increasing demand for environmentally friendly building materials, the improvement and application of HPC will continue to expand.

Investigating the Influence of Fluctuating Humidity and Temperature on Creep Deformation in High-Performance Concrete Beams: A Comparative Study between Natural and Laboratorial Environmental Tests.

To investigate the influence of temperature and humidity variations on creep in high-performance concrete beams, beam tests were conducted in both natural and laboratory settings. The findings indicate that the variations in creep primarily stem from temperature changes, whereas humidity changes have little influence on fluctuations in both basic creep and total creep. The influence of humidity on creep is more strongly reflected in the magnitude of creep. Functions describing the influence of temperature and humidity on the creep behavior of high-performance concrete (HPC) subjected to fluctuating conditions are proposed. The findings were employed to examine creep deformation in engineering applications across four places. This study complements the correction method for the creep of members under fluctuating temperature and humidity. This research application can provide a basis for the calculation of the long-term deformation of HPC structures in natural environments.

Bond-slip behaviour of textile-reinforcement in 3D printed concrete

Integration of reinforcement in extrusion-based 3D concrete printing (3DCP) is one of the significant challenges that limit its structural application. Providing textile reinforcement having high tensile strength, easy formability and non-corrosive nature as a potential reinforcement for 3DCP members enhances their structural performance. However, the bond between the printed concrete and the textile reinforcement is an essential factor that affects the composite action. This study investigates the bond-slip behaviour of three types of textile reinforcements (i.e., AR-glass, basalt and carbon) in high-performance 3D printable concrete. The bond characteristics were evaluated using pull-out load test specimens. The effect of rheological properties like viscosity and yield strength on the bond behaviour was evaluated by varying the cement content with two different replacement dosages of fly ash and slag. The modification of the nozzle to incorporate textile reinforcement as an in-process reinforcement method for 3DCP is also discussed. Test results showed that the addition of fly ash reduced the viscosity and yield strength, thereby enhancing the bond strength and pull-out load. However, reduced viscosity and yield strength resulted in poor buildability. When compared to the control mix, the mix with 15% slag replacement showed 40% increased bond strength with good buildability and easy pumping. The modified nozzle incorporates the textile reinforcement during printing, and scanning electron microscopy images show that the printable concrete was observed to bond well with the multifilament yarns of the textile. Furthermore, analytical modelling was conducted to predict the pull-out load versus slip behaviour, and a comparison of the predicted and experimental behaviour is presented.

Hybrid and ensemble models by coupled with automated meta-heuristic algorithms for compressive and flexural strength and slump of high-performance concrete

High-performance concrete (HPC) is a specialized type of concrete designed to meet stringent performance and uniformity standards that are difficult to achieve with conventional materials and standard mixing, placing, and curing methods. The testing process to determine the mechanical properties of HPC specimens is complex and time-consuming, and making improvements can be difficult after the test result does not meet the required properties. Anticipating concrete characteristics is a pivotal facet in the realm of High-Performance Concrete (HPC) manufacturing. Machine learning (ML)-driven models emerge as a promising avenue to tackle this formidable task within this context. This research endeavors to employ a synergy of ML hybrid and ensemble frameworks for the prognostication of the mechanical attributes within HPC, encompassing compressive strength (CS), slump (SL), and flexural strength (FS). The formulation of these hybrid and ensemble constructs was executed through the integration of Support Vector Regression (SVR) with three distinct meta-heuristic algorithms: Prairie Dog Optimization (PDO), Pelican Optimization Algorithm (POA), and Mountain Gazelle Optimizer (MGO). Some criteria evaluators were used in the training, validation, and testing phases to assess the robustness of the established models, and the best model was proposed for practical applications through comparative analysis of the results. As a result, the hybrid and ensemble models were the potential methods to predict concrete properties accurately and efficiently, thereby reducing the need for expensive and time-consuming testing procedures. In general, the ensemble model, i.e., SVPPM, had a more suitable performance with high values of R2 equal to 0.989 (MPa), 0.984 (mm), and 0.992 (MPa) and RMSE = 3.82 (MPa), 9.5 (mm), and 0.30 (MPa) for CS, SL, FS compared to other models, respectively.