Properties Of High Performance Concrete Research Articles

Experimentally evaluation of high-performance concrete mixes used for tunnels and containing silica fume and polypropylene fiber after exposed to high temperatures

This work introduces an experimental study to evaluate the effect of elevated temperatures on the mechanical properties of high-performance concrete (HPC) mix with changes in Water-Cementitious ratios, W/(C+SF), Silica Fume percent, SF, and Polypropylene, PP, fiber contents. This mix was typically designed to satisfy the requirements of tunnel concrete. The compressive and indirect tensile strengths were measured at room temperature, RT, and after exposure to 400°C and 800°C. Moreover, SEM micrograph and EDS spot analysis tests were done to evaluate the effect of elevated temperatures. Fifteen mixes of HPC with different ratios of W/(C+SF), SF, and PP fiber were tested. According to the test results, the compressive strength values of design mixes increased significantly after exposure to 400°C. Moreover, using SF = 10%, the results indicated remarkable improvements in the compressive strength at 400°C and 800°C, in the case of the W/(C+SF) ratio of 0.31. On the other hand, the highest effect of the presence of PP fibers was 0.211, depending on variable ratios of the W/(C+SF) ratio and the SF content. In the case of PP=0.106 and SF=10%, the mass loss was higher at exposure to temperatures of 800°C.

Mechanical Properties of High-Performance Concrete with Steel Fibers Oriented by an Electromagnetic Field

Mechanical Properties of High-Performance Concrete with Steel Fibers Oriented by an Electromagnetic Field

Effects of submicron-MgO and nano-MgO on the expansion and microscopic properties of high-performance concrete

Effects of submicron-MgO and nano-MgO on the expansion and microscopic properties of high-performance concrete

Change of the Structural Properties of High-Performance Concretes Subjected to Thermal Effects.

The paper refers to studies of the structure of high-performance concrete with polypropylene fibre at different dosages. The authors see a research gap in the study of the effect of adding polypropylene fibre on the parameters of concrete exposed to high temperatures. The study takes into account the thermal effect—groups of samples were heated to 200 °C, 400 °C and 600 °C. The authors carried out basic tests to describe the changes in density, ultrasonic tests, uniaxial compression strength tests and tensile tests by splitting. The positive effect of polypropylene fibres is mainly observed between 20 °C and 200 °C. The melting of polypropylene fibres causes a delay in the development of micro-cracks in the structure of these concretes compared to HPC. Adding polypropylene fibres to the mixtures also increased the speed of ultrasonic wave propagation in the medium. The research was deepened with tomographic imaging. A description of the splitting surface was carried out. The results of tensile by splitting tests clearly show an increase in the relative failure area for unheated concretes in proportion to the number of fibres used. Changes in splitting surfaces under the influence of temperature are graphically illustrated. Furthermore, differences in the samples under the influence of heating at high temperatures are presented. Finally, the porosity development of all sample groups before and after heating at all temperatures is described.

A Study on the Effect of Nano-Silica on Mechanical and Durability Properties of High-Performance Concrete

This study presents experimentally the combined effect of using Nano-silica, Alccofine, GGBS, and steel fibers on the mechanical properties of hardened concrete. Nano-Silica, Alccofine, and GGBS are used as partial cement replacement by different percentages, and Steel Fiber is used as volume substitution by different percentages. Compressive strength, splitting tensile strength, and flexural strength are evaluated using different combinations between Nano-Silica, Alccofine, and GGBS. Significant improvement in the mechanical properties of concrete is observed on using Nano-Silica due to its high pozzolanic activity. The Optimum content of Steel Fiber is improved splitting tensile strength by 1%t percentage respectively compared to control mix concrete. Utilizing Nano-Silica and GGBS with Steel Fiber leads to improving compressive strength compared to other concrete mixes. Flexural strength is doubled for using Nano-Silica, GGBS, and Steel Fiber compared to other concrete.

Evaluation of mechanical properties and environmental impact of using limestone powder in high-performance concrete

In this study, various dosages of limestone (LS) powder (10, 15 and 20%) of varying fineness were used as a replacement for cement to investigate its influence on the selected properties of high-performance concrete (HPC). The efficiency factor and carbon dioxide (CO2) equivalent emissions were evaluated for life cycle assessment of HPC mixtures containing LS powder. The workability, compressive, split tensile and flexural strength, semi-adiabatic temperature rise and autogenous shrinkage of HPC were investigated. The results indicated that workability and density were enhanced by replacing cement with fine and intermediate LS powder in comparison with coarse LS powder. The compressive, split tensile and flexural strengths were all reduced by increasing the replacement level of fine, intermediate and coarse LS powder at all curing ages. Furthermore, higher temperature peaks and high autogenous shrinkage were observed in fine LS mixtures due to the nucleation effect and the accelerating hydration reaction of fine LS particles. The highest efficiency factor and highest reduction in carbon dioxide equivalent emissions was observed in the mixtures containing 20% coarse LS powder followed by the intermediate LS powder. This research work may help in understanding the role of varying finenesses of LS powder as a viable material in high-performance-based composites.

Effect of recycled waste glass on the properties of high-performance concrete: A critical review

Solid waste disposal is one of the major environmental concerns. Disposal of waste glass into open areas and landfills is one of the major threats that pollutes the environment in addition to the cases of health hazards around the world. Recycling the discarded glass as a sustainable construction material have received an increasing attention in the construction industry as it may mitigate the greenhouse emissions and potential environmental risks. This paper presents a brief review on the fresh, mechanical and durability properties of normal and high-performance concrete containing waste glass aggregates (WGA). The size, type, replacement ratio of the WGA, in addition to the mixing and curing methods of concrete significantly affects the mechanical and durability characteristics. The concrete containing powdered glass exhibited superior durability properties on account of the refined pore structure and densified microstructure. The findings exhibited that waste glass can be potentially utilised as coarse and fine aggregates in concrete production, along with the advanced recommendations for further studies.

Mechanical and Durability Properties of High-Performance Concrete Incorporating Fibers and Algerian Natural Pozzolans in Chloride Attack

This study aims to assess the effect of sodium chloride attack on the mechanical and durability properties of high-performance concrete (HPC) based on fibers and natural pozzolans. The resistance of specimens against chemical attack is determined by the unit weight, compressive strength, splitting-tensile strength, chloride ion permeability, apparent gas permeability, and visual inspection after 28, 90, 180, and 365 days of testing. A total of three types of concrete are assessed: reference concrete (RC), HPC, and high-performance fiber-reinforced concrete (HPFRC) stored in tap water and aggressive water (i.e., a 10% NaCl solution). The test results demonstrate that the presence of fibers negatively affects the permeability of HPC. However, HPC and HPFRC remain stable and are not influenced by the NaCl solution compared to RC. The natural pozzolans attenuate the side effect of fibers by occupying voids (i.e., the filler effect) and generating denser products (i.e., the pozzolanic reaction) in the cement matrix.

Effect of cavity defect on the triaxial mechanical properties of high-performance concrete

Effect of cavity defect on the triaxial mechanical properties of high-performance concrete

Influence of steel fiber and polyvinyl alcohol fiber on properties of high performance concrete

AbstractTo investigate influence of the single steel fibers, single polyvinyl alcohol fiber (PVA) and hybrid fibers on the properties of high performance concrete (HPC), the tests of the fresh properties, compressive strength, flexural strength and toughness of HPC reinforced with steel fiber and PVA fiber were conducted. The toughness of hybrid fiber HPC was evaluated through several flexural performance analysis methods and improved flexural toughness evaluation methods. In order to analyze the fiber toughening principle and the effect of different fiber content on flexural strength, the four‐point bending test was simulated by finite element modeling. And the calculation formula of hybrid steel‐PVA fiber HPC flexural strength was proposed. The results indicate that, steel fibers, PVA fibers and hybrid fibers can both improve HPC strength and toughness, while the content of PVA fiber had a critical value about 1%. If it is greater than this value, the enhancement of toughness will be reduced. Furthermore, the steel fiber and PVA fiber can play a bridging role in different scales to improve the toughness and strength of HPC.

Contribution of TiO2 and ZnO nanoparticles to the hydration of Portland cement and photocatalytic properties of High Performance Concrete

This paper aims to study the hydraulic and photocatalytic behavior of mixtures based on TiO2 and ZnO nanoparticles in cement pastes and High Performance Concretes (HPCs) for the self-cleaning application of building materials. The two nanoparticles were used to partially replace the cement of varying values from 0% to 3% by weight. Cement pastes were characterized by X-ray diffraction, X-Ray Fluorescence, Differential Scanning Calorimetry and Thermogravimetric analyzes to study their compatibility in the cement matrix. The addition of TiO2 in Portland cement resulted in better reactivity by the large presence of hydration products and the appearance of unreacted anatase titanium oxide which is responsible for the photocatalysis process. The cement pastes containing ZnO had clearly indicated the retarding effect of zinc in the hydration of Portland cement. The photocatalytic properties are determined by studying the efficiency of the degradation of nitrogen oxides (NOx) and by monitoring the discoloration of Rhodamine B under UV irradiation of HPC samples. The results showed that the introduction of titanium oxides in the HPCs exhibited a significant degradation efficiency compared to zinc oxide and the samples containing the later underwent greater discoloration of the red color coordinate (Rt).

Rheological properties of sonogel and comparison with rheological properties of high-performance concrete

This paper deals with the measurement and comparison of the rheological properties of sonogel and high-performance concrete (HPC). Measurements were made with two different instruments. The Mars II rheometer was used to measure the absolute data of the sonogel. Comparative measurements of HPC and sonogel were performed with HAAKE VISCOTESTER iQ. The flow curve test and the stress growth test were performed. The thixotropy behavior of sonogel was investigated as well. The results are presented in the context of the magnetic orientation of fibers in cement composites.

Early Age Properties of High-Performance Concrete

High Performance Concrete is used to not only minimize the environmental footprint of the cement and concrete industry, but also to enable the design and rapid construction of taller and more slender structures. Despite the significant change in concrete property requirements, the properties of concrete as used during design of concrete structures are mostly still based on 28-day water cured compressive strength, stiffness, long term drying shrinkage and creep. The relevance of these measured properties on the actual behaviour of the structure should be questioned as high strength concrete is known to have low water/cement ratios resulting in significant early age shrinkage, which is currently not taken into account by designers. This paper is based on a study where the early age properties of concrete was investigated, with specific focus on the first 24 hours after casting. The effect of factors such as low water/cement ratio, admixtures, ambient and material temperatures, shutter type and cast volume on properties such as setting time, early age shrinkage, strength development and stiffness was studied and observed trends discussed in this paper.

Influence of Internal Curing Materials on Durability Properties of High-Performance Concrete

Influence of Internal Curing Materials on Durability Properties of High-Performance Concrete

Computation of High-Performance Concrete Compressive Strength Using Standalone and Ensembled Machine Learning Techniques.

The current trend in modern research revolves around novel techniques that can predict the characteristics of materials without consuming time, effort, and experimental costs. The adaptation of machine learning techniques to compute the various properties of materials is gaining more attention. This study aims to use both standalone and ensemble machine learning techniques to forecast the 28-day compressive strength of high-performance concrete. One standalone technique (support vector regression (SVR)) and two ensemble techniques (AdaBoost and random forest) were applied for this purpose. To validate the performance of each technique, coefficient of determination (R2), statistical, and k-fold cross-validation checks were used. Additionally, the contribution of input parameters towards the prediction of results was determined by applying sensitivity analysis. It was proven that all the techniques employed showed improved performance in predicting the outcomes. The random forest model was the most accurate, with an R2 value of 0.93, compared to the support vector regression and AdaBoost models, with R2 values of 0.83 and 0.90, respectively. In addition, statistical and k-fold cross-validation checks validated the random forest model as the best performer based on lower error values. However, the prediction performance of the support vector regression and AdaBoost models was also within an acceptable range. This shows that novel machine learning techniques can be used to predict the mechanical properties of high-performance concrete.

Evaluation of strength parameters of ultra-fine flyash and nanosilica incorporated High-Performance Concrete

The effect of ultra-fine fly ash (UFA) and nanosilica on the strength properties of High-Performance Concrete are investigated in this study (HPC). Cement was replaced in varying batches with UFA at 0%, 10%, 20% and 30% by weight of cement. Nanosilica was added at a rate of 0 %, 1.5 %, 3.0 %and 4.5 %by weight of the binder. Water-to-binder ratios of 0.3, 0.325, 0.375, 0.4, and 0.425 were used in the mix design. All of the concrete mixes were evaluated for compressive strength at 7, 28, and 90 days, as well as split tensile and flexural strength at 7 and28 days. Conclusions were drawn by comparing the results with conventional concrete. The HPC with 10% UFA, 3.0% nanosilica, and 0.30 water-to-binder ratio had the best results, with compressive strength gains of 28.24 %, 28.11 %, and 31.89 % at7, 28, and 90 days, respectively. Tensile strength increased by 21.84 percent and 38.56 percent after seven and twenty-eight days, respectively, while flexural strength improved by 39.26 percent and 24.37 percent. Mathematical relationships between cube compressive strength and split tensile strength, as well as flexural strengths, were developed as a result of this research.

Influence of nano-silica on the microstructural and mechanical properties of high-performance concrete of containing EAF aggregate and processed quarry dust

The present study investigates nano-silica (NS) in ternary binder composite and the influence of the same on Electrical Arc Furnace (EAF) slag coarse aggregate-based various high-performance concrete (HPC) mixes. Processed Quarry Dust (PQD) was used as fine aggregate throughout the investigation to limit the consumption of natural river sand and make HPC more sustainable. Control HPC was designed using the Ordinary Portland Cement (OPC)- Ground Granulated Blast Furnace Slag (GGBS) binary binder and various replacement levels of natural crushed granite rock aggregate by EAF coarse aggregate. Additionally, the binary binder composite was added with colloidal nano-silica to achieve high strength HPC. A microstructure study was carried out on paste samples of OPC, OPC with GGBS, and OPC, GGBS with the inclusion of nano-silica. FESEM, EDX, XRD, FTIR, and TGA results showed that the addition of nano-silica has significantly enriched the microstructure characteristics of the binder system. The slump flow of HPC mixes decreased drastically with the inclusion of nano-silica and EAF aggregate. Mechanical properties viz., compressive strength, split tensile strength, flexural strength, and modulus of elasticity of HPC mixes containing EAF and nano-silica have exhibited superior results due to the synergetic effect of nano-silica as well as the more robust physical characteristics of EAF aggregate compared to natural crushed granite rock aggregate. The UPV values and water absorption tests have shown that nano-silica positively affects the binder composite system.

Combined effect of metakaolin and hybrid fibers on the strength properties of high performance concrete

This study aims to investigate the combined effects of Metakaolin (MK) and Hybrid fibers on High-Performance Concrete's (HPC) mechanical properties. A constant proportion of 0.25% for polypropylene fibers (PF) and varying proportions of 0%, 0.5%, 0.75% and 1.0% for steel fibers (SF) making a total fiber volume fractions of 0%, 0.75%, 1.0% and 1.25% were used to develop hybrid fiber-reinforced high-performance concrete (HFRHPC). Four replacement levels for hybrid fibers by volume of the binders and four partial replacement levels for Metakaolin (0%, 10%, 20% & 30%) by weight of cement have been considered for three different water binder ratios (0.275, 0.325 & 0.375). An aggregate binder ratio of 1.75 was kept constant. The test results reveal a maximum increase of 31.83%, 37.05%, and 36.53% in compressive strength for curing periods of 7, 28, and 56 days, respectively. The split tensile strength, flexural strength, and impact strength test results show an increase of 42%, 74.41%, and 68.32% for a curing period of 28 days, respectively. Additionally, linear regression analysis was performed, and plots of compressive strength v/s tensile strength and compressive strength v/s flexural strength have been obtained to develop a relationship between compressive strength, tensile strength, and flexural strength. With the incorporation of metakaolin and hybrid fibers into the concrete matrix, very high mechanical properties could be achieved. The results indicate that a combination of 1.25% hybrid fibers and 10% Metakaolin gains all the water-binder ratios' highest strength.

Influence of Fiber Addition on the Properties of High-Performance Concrete.

High performance fiber-reinforced concrete (HPFRC) has been frequently investigated in recent years. Plenty of studies have focused on different materials and types of fibers in combination with the concrete matrix. Experimental tests show that fiber dosage improves the energy absorption capacity of concrete and enhances the robustness of concrete elements. Fiber reinforced concrete has also been illustrated to be a material for developing infrastructure sustainability in RC elements like façade plates, columns, beams, or walls. Due to increasing costs of the produced fiber reinforced concrete and to ensure the serviceability limit state of construction elements, there is a demand to analyze the necessary fiber dosage in the concrete composition. It is expected that the surface and length of used fiber in combination with their dosage influence the structure of fresh and hardened concrete. This work presents an investigation of the mechanical parameters of HPFRC with different polymer fiber dosage. Tests were carried out on a mixture with polypropylene and polyvinyl alcohol fiber with dosages of 15, 25, and 35 kg/m3 as well as with control concrete without fiber. Differences were observed in the compressive strength and in the modulus of elasticity as well as in the flexural and splitting tensile strength. The flexural tensile strength test was conducted on two different element shapes: square panel and beam samples. These mechanical properties could lead to recommendations for designers of façade elements made of HPFRC.

Evaluation of Strength Parameters of Metakaolin and Nanosilica Incorporated High-Performance Concrete

This article presents the evalution of strength properties of High-Performance Concrete (HPC) due to the addition of nanosilica and metakaolin. Metakaolin partially replaces the cement at 10%, 20%, and 30% by weight. The addition proportions of nanosilica are 0%, 1. 5%, 3.0%, and 4.5% by weight of binder for each of the metakaolin replacement levels. Water-to-binder ratios of 0.3, 0.325, 0.35, 0.375, 0.4, and 0.425. The hardened HPC mixes were tested for their compressive, split tensile, and flexural strength at 7 and 28 days. Additionally, the compressive strength test was carried out after 90 days of curing to study the long-term strength development. The obtained results were compared with conventional concrete as a reference mix. HPC with 10% metakaolin, 3% nanosilica and 0.3 water-to-binder ratio yielded the best performance with 36.11%, 31.75% and 34.59% improvement in 7, 28 and 90 days compressive strength respectively. The improvement in split tensile strength were 25.24% and 40.26% at 7 and 28 days respectively. The flexural strength was enhanced by 41.10% and 30.30% at 7 and 28 days respectively. Furthermore, mathematical relationships between cube compressive strength and split tensile strength, flexural strength were derived from the experimental results of this investigation.