Properties Of High Strength Concrete Research Articles

Mechanical Properties of High-Strength Concrete Reinforced with Hybrid Basalt–Polypropylene Fibers under Dynamic Compression and Split Tension

Mechanical Properties of High-Strength Concrete Reinforced with Hybrid Basalt–Polypropylene Fibers under Dynamic Compression and Split Tension

Mechanical properties of high-strength concrete (HSC) under projectile penetration

With the advancement of weapon systems, high-strength concrete (HSC) has been extensively utilized in protective engineering. To investigate the damage characteristics of HSC under impact resistance, this study first conducted Split Hopkinson Pressure Bar (SHPB) tests on HSC, along with cyclic loading and unloading tests. Based on the test data of SHPB and cyclic loading and unloading, the original Holmquist-Johnson-Cook (HJC) model was adjusted accordingly. Additionally, tungsten alloy bullet penetration tests on concrete plates with different initial velocities were performed to measure the depth of penetration (DOP) and crater area corresponding to each velocity. A numerical model was then established using Abaqus software. The test results and numerical simulations were compared and analyzed, demonstrating that the predicted results closely matched the test, with a DOP error margin of less than 10 %. This confirmed the feasibility and accuracy of the modified model and its parameters. Finally, the results of numerical simulation were used to analyze the mechanical properties of HSC during impact resistance.

An Experimental Study on the Influence of Different Cooling Methods on the Mechanical Properties of PVA Fiber-Reinforced High-Strength Concrete after High-Temperature Action.

High-strength concrete (HSC) has a high compressive strength, high density, excellent durability, and seepage resistance, but its deformation ability is weak. Adding fibers can improve the physical and mechanical properties of HSC. Additionally, the HSC structure may face the threat of fire. In the process of fire extinguishing, the damage mechanism of high-temperature-resistant concrete is complicated due to the different contact conditions with water at different locations. Hence, it is essential to conduct pertinent research on the behavior of fiber-reinforced HSC with different cooling methods after high-temperature action. In this paper, polyvinyl alcohol fiber (PVA fiber) was selected to be added into the HSC to carry out high-temperature experimental research, so as to explore the apparent changes, failure pattern, and mass loss rate of the fiber-reinforced HSC using different cooling methods and analyze the influence of its residual compressive strength and flexural strength. The test results suggest that, with the increase in heating temperature, the color of the specimen's surface transitions from dark blue-gray to white, and the quantity of surface cracks on the specimen gradually rises. The mechanical strength gradually decreases as the heating temperature increases. At a consistent heating temperature, the mechanical strength initially rises, and then falls with an increase in fiber content. The maximum compressive strength and flexural strength were achieved at PVA fiber contents of 0.2% and 0.3%, respectively. For different temperatures and fiber contents, the mechanical strength after natural cooling is generally higher than that after immersion cooling. In addition, X-ray polycrystalline diffractometry (XRD) and scanning electron microscopy (SEM) tests were conducted to analyze the compositional alterations and microstructure of the fiber-reinforced HSC following high-temperature exposure, accompanied by an explanation of the factors influencing the alterations in the physical and mechanical properties. Therefore, the findings of this study can serve as a valuable reference for the utilization of HSC in engineering structures and contribute to the advancement of HSC technology.

Load path dependence for passively and actively confined high-strength concrete

The assumption of load path independence has been instrumental in developing analysis-oriented stress-strain models for FRP-confined concrete. However, there remains no consensus on this assumption when applied to high-strength concrete (HSC). An axial stress gap is typically observed between active and passive confined HSC cases, even when their confinement conditions and deformations are identical. To address the existing research gap, this study conducted experimental tests on a series of HSC specimens under various levels of active and passive confinement. These tests aimed to assess the influence of the stress disparity between the two confinement mechanisms. Cyclic loading was also applied to the confined HSC specimens to derive damage indices (plastic strain, tangent unloading stiffness, and reloading stiffness) and to establish their relationship with the stress gaps. The findings revealed that the stress gap identified from different confinement types increases with the strength of the concrete. It also varies with the axial strain, exhibiting a trend that initially increases and then decreases. The test results further indicated that the presence of this stress difference is a response to internal damage within the concrete. Specifically, under different confinement paths, a reduction in the plastic strain difference that characterizes the damage will lead to a decrease in the stress gap. Moreover, under large deformations, the severe internal damage condition in concrete also reduces the damage differences for HSC experiencing different load paths, which in turn diminishes the stress gap. These insights provide a deeper understanding of how different confinement mechanisms affect the material properties of HSC under various load paths.

The influence of slag content on the mechanical properties of high-strength concrete

In light of the current situation where excessive amounts of excavated earth from subway tunnel construction are being stacked with low utilization and value, this study used residue as a mineral admixture to investigate the effects of different proportions of residue content (0%, 2.5%, 5.0%, 7.5%, and 10.0%) on the workability and mechanical properties of C50 concrete. The results indicate that: (1) The initial slump and slump loss of C50 concrete decrease gradually as the residue content increases. (2) The compressive strength of C50 concrete with varying residue contents is lower than the control group at early stages (3d, 7d), while it is higher than the control group at 28d. There exists an optimal content of residue for improving C50 concrete compressive strength, and it is found that the highest compressive strength at 28d is achieved when the residue content is 7.5% of the cement content. (3) The microscopic structure of C50 concrete with different residue contents at 28d shows that as the residue content increases, the microscopic structure of C50 concrete gradually becomes more compact and the porosity decreases.

Durability and ecological assessment of low-carbon high-strength concrete with short AR-glass fibers: Effects of high-volume of solid waste materials

The goal of this research is to improve the mechanical characteristics and durability of concrete while adhering to green and sustainable development principles. Portland cement (PC) was replaced with ceramic waste powder (CWP), glass powder (GP), and granite waste powder (GWP) to create the low-carbon, high-strength concrete (HSC). These materials were incorporated at 0–50% as a partial replacement of PC. The short alkali-resistant (AR-) glass fiber content was added by 1.0% of the PC content. The changes in strength, microstructure, pore structure, as well as ecological assessment of HSCs was investigated. Various experiments on the durability properties and elevated temperature resistance of HSC were performed. The experimental results show that mechanical properties of HSC with 10%GP and 20%GWP were maximally enhanced at 28d, while the mechanical properties of HSC with 50% of all wastes are decreased. It was found also that HSC containing CWP showed significant reductions in carbonation depth (up to 65.89% lower than the control mixture), especially at higher replacement levels. Furthermore, the increment in substitution level of CWP has found an increment in pore volume, resulting in a reduction in preliminary strength performance. It was observed that a 50% substitution level of GP and GWP reduced the water penetration depth by 47.71% and 65.7% compared to the control mixture, respectively. The residual strength after 600 °C exposure for 10%CWP, 10% GP, and 20% GWP retained about 34.10%, 32.32%, and 43.29%, respectively, from their original strength. XRD tests and SEM micrographs showed that adding 10%GP and 20%GWP improve the hydration reactions. Finally, environmental assessments revealed that incorporating CWP, GP, and GWP into HSC led to reduced costs, energy consumption, and carbon footprint.

Sustainable reuse of waste ceramic tiles powder and waste brick powder as a replacement for cement on green high strength concrete properties

Nowadays, reducing construction waste has grabbed the attention. As bricks and ceramic tiles represent more than 50% of the ceramic waste in many European countries. Thus, the recycling of this waste type is one of the most significant challenges within the paradigm of the circular economy. This paper investigated the impact of substitution levels of cement by waste ceramic powder (WCP) and waste brick powder (WBP) at 0%, 5%, 10% and 15%, on the HSC characteristics. The WBP and WCP materials were characterized in detail by laser granulometry, XRF and XRD measurements, followed by standard mixing, production, and curing of concrete samples. The experiments on dry density, modulus of elasticity, flexural strength, splitting tensile strength, compressive strength, resistance to sulfate attack, water absorption and ultrasonic pulse velocity were conducted to evaluate the hardened properties of concrete. It was demonstrated that the durability and strength of concrete containing WBP and WCP as partial replacements for cement are marginally inferior to those of the control sample. On the other hand, samples containing WBP had a lesser negative effect on HSC properties in comparison with samples containing WCP. However, employing a 5% WBP with 10% WCP mixture enhanced the characteristics of the HSC in comparison to samples containing various percentages of WCP individually. In addition, the microstructure analyses revealed that the addition of 10% WCP and 5%WBP to HSC specimens resulted in higher hydration products and a slightly denser concrete matrix compared to samples containing various percentages of WCP individually. Research findings indicate that a 15% substitution of cement with WCP or WBP illustrated an environmental benefit in concrete production due to a 13.1% reduction in specific energy consumption.

Potential usage of fly ash and nano silica in high-strength concrete: Laboratory experiment and application in rigid pavement

High-strength concrete (HSC) using supplementary cementitious material of 30% fly ash (FA) and various nano silica (NS) contents were investigated in this study. FA and NS are waste materials collected from local thermal plants and rice husk ash in Southern Vietnam, respectively. Different concentrations of NS at 0%, 0.5%, 1.0%, and 1.5% were incorporated into the base mixture in place of cement and FA. The water-to-binder ratio of 0.32 was constant for all the mixtures. Results indicated that the combination binder of cement, FA, and NS satisfied the setting time as pure cement binder. The slump test value was in the range of 30–40 mm by adjusting the superplasticzer. Mechanical properties of HSC were studied at various curing ages of 3, 7, 28, and 56 days, including compressive strength, flexural strength, elastic modulus, and abrasion resistance. Results indicated that 1% NS can be considered as optimum content for preparing an HSC mixture, which showed the best mechanical properties. Furthermore, a good correlation between compressive strength and flexural strength was obtained from the results. Finally, rigid pavement calculation revealed that the addition of 1% NS resulted in a reduction in the thickness of the concrete slab by 30 mm (around 10.7%) compared to non-NS concrete. These findings suggest that incorporating nano-silica into concrete can lead to thinner concrete slabs with improved performance characteristics.

The effect of particle sizes of steel slag as cement replacement in high strength concrete under elevated temperatures

This study investigates the impact of utilizing steel slag (SS) as a partial substitute for cement in high strength concrete (HSC) under high temperatures covering a range from 200 °C to 800 °C over a duration of 2 h. Two particle sizes of SS: 75 µm and 150 µm, were utilized as fine steel slag (FSS) and coarse steel slag (CSS). This study evaluates several physicochemical and compressive strengths of the HSC. After conducting the compressive strength, both residual compressive strength (RCS) and relative residual compressive strength (RRCS) were calculated. Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and X-Ray Diffraction (XRD) analysis were carried out to analyze the physicochemical properties of HSC before and after subjected to elevated temperatures. The findings indicate an increase in the RCS of all specimens up to 400 °C. The replacement of FSS for cement enhances the compressive strength of HSC at ambient temperature, and FSS performs better than CSS up to 200 °C. However, beyond 400 °C, CSS exhibits a superior RRCS compared to FSS. XRD analysis confirms mineralogical changes in the HSC after exposure to fire, including the decomposition of C-S-H gel and the conversion of calcium hydroxide into calcium carbonate. The present study suggests that incorporating CSS in HSC has the potential to enhance its performance under high temperature conditions.

Suitability of marble powders in production of high strength concrete

A tremendous amount of non-biodegradable waste is created during mining and processing tasks of layered stones like marble. Over time, this has become a global problem because it harms the environment in multiple ways. Hence, it is necessary to find an alternate way to securely dispose and reuse marble wastes. The construction sector is one of the significant consumers of natural resources for the production of material binders and aggregates. As a result, in recent years, number of researchers have carried out studies in which various kinds of marble waste have been incorporated into concrete with the intention of substituting either cement or aggregates or both. This paper presents the effect of two locally sourced waste marble powders Kadapa marble powder (KMP) and Bethamcherla marble powder (BMP) as partial replacement of cement on mechanical and durability properties of high strength concrete (HSC). Their effect at different replacement levels in HSC is evaluated in compressive, indirect tensile and flexural strengths, elastic modulus, chloride penetration resistance and freeze–thaw durability properties. Micro-structural investigation is also conducted to evaluate their impact on the matrix of HSC containing waste marble powders as additional cementitious materials. Results show that the HSC consisting of KMP and BMP content of 10% and 15%, respectively exhibited higher mechanical and durability properties than the control HSC. Micro-structural investigation also supports this finding. It can be concluded that the use of marble powders as partial replacement of cement does not have any adverse impact on the properties of concrete. The use of KMP and BMP reduces the vast amount of energy required to produce cement, cost and time with reduction in environmental hazards.

The Effects of Recycled Carbon Fibers on the Mechanical Properties of High-Strength Concrete and Its Resilience to Impact

The Effects of Recycled Carbon Fibers on the Mechanical Properties of High-Strength Concrete and Its Resilience to Impact

Experimental Analysis of High-Strength Concrete Using Granite Aggregates

The present study investigates the effect of incorporating metakaolin and silica fumes in the production of high-strength concrete along with partial replacement of coarse granite aggregates in the high-strength concrete. The higher compressive strength, refined microstructure, and decreased permeability of high-strength concrete are some of the properties responsible for its trending use in the modern construction industry. The main purpose of this research is to evaluate the effect of the replacement of coarse granite aggregates with natural aggregates on the mechanical and durability properties of high-strength concrete. For understanding the effect of metakaolin, silica fume, and granite aggregates on the properties of high-strength concrete, various specimens such as cubes, cylinders, and cylindrical discs were cast and tested after 7, 14, and 28 days of curing. Various concrete mixes were prepared by adding silica fume at 5%, 7.5%, and 10% and metakaolin at 5%, 7.5%, 10%, 12.5%, and 15% in concrete production. Furthermore, High-strength concrete mixes were also prepared by replacing natural coarse aggregates with granite coarse aggregates by 25%, 50%, 75%, and 100% to study the effect of replacement percentage on the concrete properties. Test results indicated that the compressive strength and split tensile strength of the concrete mix increased with the increase in the replacement percentage of granite aggregates, with the highest strength seen at complete replacement with granite aggregate due to the enhanced compressive strength of such aggregates in comparison with the natural coarse aggregates. In various mixes cast using metakaolin and silica fume, the highest compressive strength was seen in a mix containing 10% metakaolin and 7.5% silica fume, and results of other mixes indicated that the use of silica fume and metakaolin are viable options for high-strength concrete production in our experimental study.

Behaviour of FRP-ECC-HSC composite stub columns under axial compression: Experimental and mathematical approach

The composite stub column composed of fiber-reinforced polymer (FRP), Eco engineered cementitious composite (ECC), and high-strength concrete (HSC) core is experimentally investigated in this study. The ductile performance of HSC-FRP is enhanced by proving an ECC ring of 30 mm thickness as sandwich layer between HSC and FRP. During experimentation the premature failure of the FRP-HSC column is observed at the initial phase, which exhibits brittle nature of the column. The material properties of FRP, ECC, and HSC were characterized. The performance of composite columns was observed with four FEH (FRP-ECC-HSC) columns, four HE (HSC-ECC) columns, and two FH (FRP-HSC) columns. The parameters such as uniform hoop strain distribution, ultimate load-carrying capacity, axial and hoop strain, and confining efficiency of the FRP were investigated to understand the behaviour of composite columns. From results, the ultimate load-carrying capacity of FH columns was 15.56 % higher than the FEH columns. The FEH columns showed the enhanced confining efficiency of FRP and 21% increase in uniform hoop strain distribution than the FH columns. The hoop strain capacity of FEH columns were increased twice the times of FH columns, which indicates the increased ductile behaviour of the FEH columns. In addition, experimental results of composite columns were highly correlated with the existing theoretical equation from literatures

A Parametric Study on Fibre Reinforced Concrete

Abstract: The investigation is focused to study the effect of various types of fibres on compressive strength, split tensile strength and flexural strength of High strength concrete. The water to cementitious material ratio considered for the study of High strength concrete was 0.25. The content of silica fume and fly ash in every mix was 5% and 10% by the weight of cementitious material. Two types of fibres considered for the study include, Polypropylene Fibres (PF) and Flat Steel Fibres (FSF). Dosage of fibre was varied from 0.5% to 4% at an interval of 0.5% by weight of cementitious material. Type of cement, fine aggregate, coarse aggregate, type of Superplasticizer and its dosage are kept constant in every mix. The use of High Strength Concrete (HSC) is increased now a days. It is observed that HSC relatively brittle material. Fibres are added to improve its ductility. Experimental study is carried out to assess mechanical properties of high strength concrete (HSC) of grade M70.

The combined effect of steel fiber and MgO on the deformation and mechanical properties of high-strength concrete

Shrinkage cracking of concrete is one of the main problems affecting the durability of high-strength concrete. One of the main measures to solve this problem is to use expansion agents to compensate for the shrinkage of concrete. But on the other hand, excess expansion, while compensating for shrinkage, is likely to have a detrimental effect on mechanical properties of concrete. Especially for bridge decks and airport pavement with high requirements for impact resistance, toughness, and crack resistance, the use of expansion agents alone cannot meet the performance requirements. In this study, the mechanical properties and autogenous shrinkage of concrete were studied when MgO expansion agent (MEA) and steel fiber were used simultaneously. The results showed that the expansion produced by MEA increased the porosity while compensating for the shrinkage of concrete. Compared with plain concrete, the porosity increased by 4.4% when MEA was incorporated alone. After MEA and steel fiber were used simultaneously, the steel fiber constrained the expansion of MEA through the adhesive friction between fiber and matrix, which made the interface transition zone (ITZ) between cement paste and fiber densified. In this way, the shrinkage of concrete was avoided without reducing the mechanical properties. Especially when 8% MEA and 1% steel fiber were used simultaneously, the compressive strength and splitting tensile strength of concrete were increased by 20.6% and 65.0% respectively, and the porosity was decreased by 20.9%. The expansion of concrete at 410d when used simultaneously was 371 × 10−6, which was 20.7% lower than that of MEA alone, avoiding the possible adverse effects of excessive expansion of MEA. The research results have guiding significance for improving the crack resistance and impact resistance of concrete.

Mathematical Modeling for Evaluating the Mechanical Properties of High Strength Concrete with Natural Zeolite and Additives

Mathematical Modeling for Evaluating the Mechanical Properties of High Strength Concrete with Natural Zeolite and Additives

Influence of Natural Fiber Derived from Agricultural Waste on Durability and Micro-Morphological Analysis of High-Strength Concrete

This research focuses on the investigation of durability behavior and microstructural analysis for M70 grade of high-strength concrete (HSC) with the influence of alccofine, banana fiber (BF), and coir fiber (CF). In this investigation, cement was partly supplanted by 15% of alccofine content in weight. Two types of natural fibers, banana and coir fibers, were selected and added in concrete at 0.5%, 1%, 1.5%, and 2% by volume. Durability characteristics, such as long-term compressive performance, rapid chloride penetration, sorptivity, water absorption, volume of permeable voids, and acid attack resistance are investigated elaborately and correlate with conventional HSC. Results showed that the incorporation of banana and coir fibers with alccofine in HSC exhibited good durability performance as correlated with conventional HSC. At 180 days of curing, incorporating 1% of banana fiber increased the durability performance compared to reference HSC. Nonetheless, the high-fiber percentage of HSC has a slight reduction in durability characteristics. Among the two types of fibers, the banana fiber showed the most significant improvement in the durability properties of HSC. The influence of natural fiber on the microstructural characteristics of HSC was evaluated using scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) to substantiate the experimental findings. In contrast, using additional supplementary cementitious materials (SCMs) in HSC fabrication significantly reduces cement usage and carbon emissions.

Experimental investigation on workability and mechanical properties of carbon fiber reinforced high-strength concrete (HSC) containing waste bakelite aggregate (WBA)

High-strength concrete (HSC) is a type of concrete that is, due to its improved mechanical and durability properties, most often used in the construction of high-demand structures such as bridges, structural elements in aggressive environments, skyscrapers, and large-span constructions. In order to obtain high-strength concrete, a larger amount of cement is required, which can lead to questionable ecological acceptability of this material. To reduce the ecological footprint of this material, supplementary cementitious materials such as silica fume or metakaolin are often used. By reducing the porosity and increasing the density of the concrete mixture, fine particles of supplementary cementitious materials have a positive effect on the mechanical and durability properties of high-strength concrete. Along with cement and supplementary cementitious materials, another important component of high-strength concrete is aggregate, which is in most cases a fine aggregate. In this research, the natural fine aggregate was partially replaced with bakelite plastic waste, and the influence of this replacement on the fresh and hardened properties of high-strength concrete was presented. Seven mixtures were designed, a reference mixture and six other mixtures in which supplementary cementitious materials, waste bakelite aggregate, and carbon fibers were combined to produce environmentally friendly high-strength concrete. 5 % of the cement mass was replaced with silica fume or metakaolin, 10 % volume of natural fine aggregate was replaced with waste bakelite aggregate (WBA) and carbon fibers were added in the amount of 0.5 % of the cement mass. In a fresh state, the workability of HSC is determined by using a flow table. To determine the influence of waste bakelite aggregate on mechanical properties, flexural and compressive strength tests were carried out on 7- and 28-day-old samples. The test results indicate that the combined effect of waste bakelite aggregate, supplementary cementitious materials, and carbon fibers can be a promising solution not only to improve high-strength concrete mechanical properties but to potentially save millions of tons of natural fine aggregate and preserve natural resources and the environment.

Estimation of physical and mechanical properties of high-strength concrete with polypropylene fibers in high-temperature condition

High-strength concretes (HSC) have been widely applied in civil construction. However, this material does not perform well in fire situations due to spalling, a phenomenon that can be significantly mitigated by adding synthetic fibers to HSC cementitious matrix. Estimating HSC physical and mechanical properties for different compositions and temperatures can therefore be useful, as the structure may be pre-designed without requiring prior material characterization in a fire situation. With this perspective, this paper aimed to propose regression models to estimate eight properties of High-Strength Concrete with Polypropylene Fibers (HSC-PPF), namely compressive strength, tensile strength, static modulus of elasticity, dynamic modulus of elasticity, ultrasonic pulse velocity, electrical resistivity, water absorption, and weight loss, at high temperatures (up to 800 °C). For this, it was evaluated the effective correlation between mechanical responses and independent variables, such as temperature, water absorption, and dynamic modulus, and the accuracy of regression models was assessed. The results obtained indicated that, among the models proposed, the two multiple regressions were better than the simple one for estimating HSC-PPF properties since they presented high adjustments (R2) and low mean absolute percentage (MAPE), and coefficient of variation (CV) errors. This methodology can be used in a wide variety of fiber-reinforced HSCs.

A Systematic Review of Properties of High-Strength Concrete using Rice Husk ash as a Replacement

The investigation aims to analyse potential methods of augmenting high-strength concrete's (HSC) quality by incorporating Rice Husk Ash (RHA). Residue from incinerated rice husks, commonly known as RHA, has been applied to concrete to enhance material durability and strength since ancient times. Research conducted on high-strength concrete (HSC) sought to investigate how RHA affects its endurance and fortitude. The study featured a composition range from 0.3% - 1.2% RHA content density in HSC blends. It was discovered that adding RHA improved both compressive force resistance and splitting tensile control potency within these mixtures by an average increase of 6.2%, whereas abounding with up to or exceeding 14.7%. Furthermore, water permeation capabilities were bolstered alongside chloride infiltration defence attributes among this kindred variation; suggesting it could function reliably as an admixture suitable for improving structural robustness when added at significant ratios into High-Strength Concrete compositions- thereby proving itself effective overall towards achieving optimal enhancements across multiple facets affecting longevity & sturdiness alike over time through rigorous testing protocols established during our analysis period.