Properties Of High Performance Concrete Research Articles

Experimental investigation of multiscale hybrid fibres on the mechanical properties of high-performance concrete

Silica fume, nano silica, nano calcium carbonate and fly ash are used to carry out experiments on the reinforcement of concrete. The addition of 6% silica fume improves the compressive strength of concrete most significantly. Based on the best nanomaterial mix ratio for the fibre concrete matrix mix ratio, fibre-reinforced concrete mix experiments that include steel fibre, PVA (polyvinyl alcohol) fibre, basalt fibre and CaCO3 whisker are carried out. The results show that single-doped basalt fibres, single-doped PVA fibres, double-doped steel fibres and PVA fibres reduce the compressive strength of concrete to different degrees. However, these fibres all increase the flexural strength of concrete. The three fibre doping schemes, including the single-doped steel fibre, the double-doped steel fibre with CaCO3 whisker, the triple-doped steel fibre, the PVA fibre and the CaCO3 whisker, all increase the compressive strength and flexural strength of concrete. The hybrid fibre can exert the best strengthening and toughening effect on the concrete to achieve the best synergy with the right fibre content. High-performance concrete reinforced by multiscale hybrid fibres can be used for deep underground linings in all kinds of complex geologies.

Effect of Hybrid Fiber on Early Mechanical Properties of High Performance Concrete

The early mechanical properties of hybrid fiber reinforced concrete were studied by orthogonal test, the factors of steel fiber content, polypropylene fiber content and length on compressive strength and splitting tensile strength of concrete for 3 d ages were investigated, the test results were analyzed by range analysis, variance analysis and performance index analysis. The results show that the hybrid fiber has a negative hybrid effect on the compressive strength of concrete for 3 days, a positive hybrid effect on the splitting tensile strength of concrete for 3 days. When the volume fraction of polypropylene fiber is 0.1%, the length is 12mm, and the volume fraction of steel fiber is 1.5%, the compressive strength of concrete is the largest. When the volume fraction of polypropylene fiber is 0.15%, the length is 18mm and the volume fraction of steel fiber is 1.5%, the splitting tensile strength of concrete is the largest.

Optimum mix design of high-performance concrete containing micro POFA using historical data design

This paper presents the optimized mix design based on the response surface methodology (RSM) in producing high performance concrete (HPC) by utilizing palm oil fuel ash (POFA) as cement replacement material. The historical data design was used based on the existing testing data determined from the laboratory experiments. The variable in this study includes POFA percentage (10%, 20%, and 30%). The concrete mixes were tested both for fresh and hardened properties of high performance concrete. The optimized level for POFA in the HPC mix proportion was determined by the maximization of workability, early, 28 days’, and later compressive strength. The response of each mix that contains POFA showed a significant increase in the workability and compressive strength with respect to the plain HPC. The results presented the optimum solution for mix design of high performance concrete with POFA that achieve the targeted goal performance criteria (fresh and hardened properties).

A Critical Review on Effect of Nanomaterials on Workability and Mechanical Properties of High-Performance Concrete

The application of nanomaterials in high-performance concrete (HPC) has been extensively studied worldwide due to their large surface areas, small particle sizes, filling effects, and macroquantum tunneling effects. The addition of nanomaterials in HPC has great contribution to enhancing the pore size of the cementitious matrix, improving the hydration of cement, and making the matrix much denser. In order to present an exhaustive insight into the feasibility of HPC reinforced with nanomaterials, the new development of HPC was summarized and the influence of different nanomaterials on the properties of HPC was reviewed based on more than 100 recent studies in this literature review. Workability, compressive strength, tensile strength, and flexural strength properties of HPC with nanomaterials were discussed in detail. In addition, nanomaterial-modified HPC was compared with the traditional concrete and obtained a lot of valuable results. The results in the present review indicate that the addition of various nanomaterials improves the mechanical properties of HPC, while reducing the workability of HPC. However, there is an optimal dosage of nanomaterial for improving the mechanical properties of HPC. Improving the properties of HPC by adding nanomaterials is expected to become a mainstream technique in the future. This literature review can provide comprehensive and systematic knowledge to researchers and engineers working on HPC and promote the application of this new HPC in modern civil engineering.

Study on the effect of sintered flyash aggregate and steel fibre on the properties of high performance concrete

Light weight aggregates are better solutions for making the structure light weight and they are widely used in construction. Other than the light weight behaviour, the porous nature of these aggregates helps in retaining water content and aids in curing the concrete. Sintered flyash aggregate (SINTAG) is a type of light weight aggregate that can be used as coarse aggregate in concrete. Water content retained through presoaking these aggregates helps in extended hydration of cementitious materials and can increase the strength of concrete even in the absence of proper external curing practice. Steel fibre reinforcement can increase the tensile and flexural strength of concrete. Presoaked SINTAG was added by replacing various percentages of coarse aggregate volume in concrete and steel fibre was added at different percentages by volume of concrete. It was obtained that 20% replacement of coarse aggregate by volume with SINTAG increased the strength of normal concrete by 26.7 % and split tensile strength increased by 2.8%. Addition of steel fibres to SINTAG concrete at 1% increased its compressive strength additionally by 6.2% and tensile strength additionally by 35.1%. Durability studies showed that chloride ion penetration of normal and SINTAG incorporated concrete were low. Water permeability tests revealed that normal, SINTAG and fibre reinforced SINTAG concretes can be used for water retaining structures as well as aggressive environments. Flexural strength of normal RCC beam increased 7.7% when SINTAG was incorporated while it again increased 9.6% when steel fibre was added. Fibre reinforced SINTAG concrete beam showed much less deflection compared to normal and SINTAG beams.

The effect of metakaolin and hybrid polymers on the microstructure of concrete

It has been established that metakaolin (MK) can be applied as a supplementary cementitious material and that some polymers can enhance substantial properties of concrete. Previous studies showed that, when used in combination, MK and polymers can complement each other, and enhance further the mechanical and durability properties of concrete, which were not improved by one another separately. To have a deep observation and understanding of the mechanism of concretes modified with various combinations of MK and polymers, this study investigates the changes in the microstructures based on SEM combined with CT scan analysis scan technologies. The findings show that the microstructure of the pore of hardened concrete modified with combined MK and hybrid polymers is significantly improved compared to samples with MK or polymers alone. This indicates that this approach can be effectively used to provide additional proof on the strength and porosity properties of high-performance concrete.

The effect of metakaolin and hybrid polymers on the microstructure of concrete

It has been established that metakaolin (MK) can be applied as a supplementary cementitious material and that some polymers can enhance substantial properties of concrete. Previous studies showed that, when used in combination, MK and polymers can complement each other, and enhance further the mechanical and durability properties of concrete, which were not improved by one another separately. To have a deep observation and understanding of the mechanism of concretes modified with various combinations of MK and polymers, this study investigates the changes in the microstructures based on SEM combined with CT scan analysis scan technologies. The findings show that the microstructure of the pore of hardened concrete modified with combined MK and hybrid polymers is significantly improved compared to samples with MK or polymers alone. This indicates that this approach can be effectively used to provide additional proof on the strength and porosity properties of high-performance concrete.

Review paper on material properties of high performance concrete

In modern years, effective utilization of high performance concrete in construction because of their increase in durability and mechanical properties. In particular high performance concrete is made by replacing/introducing mineral admixtures and chemical admixtures with cement or replacing/introducing the fibers into the concrete. The focus of this review is to illustrate the properties of the various materials used, mix proportion of materials to make high performance concrete and observation of high performance concrete. Moreover there are three main groups which are important in manufacture of high performance concrete they are increase of workability, increase of strength and increase of durability. Finally the studies on the high performance concrete have been reviewed.

The effect of Vietnam’s nano-silica on mechanical properties of high-performance concrete

The demand for High Performance Concrete (HPC) is steadily increasing with massive developments. Conventionally, it is possible to use industrial products such as silica fume (SF), fly ash, as supplementary cementitious materials (SCM), to enhance the attributes of HPC. In recent years, nano-silica (NS) is used as an additive in added mainly to fill up the deviation arises with the addition of SF for HPC. This study aims to optimize the proportion of NS (produced in Vietnam) in the mixture used for fabricating 70 MPa high-performance concrete. SiO2 powder with particle size from 10 to 15 nm were used for mixing. A series of compressive strength test of HPC with nano-SiO2 varied from 0 to 2.8 percent of total of all binders (0%, 1.2%, 2%, 2.8%), and the fixed percentage of silica fume at 8% were proposed. Results show compressive strength increases with the increase of nano-SiO2, but this increase stops after reaching 2%. And at day 28 of the curing period, only concrete mixture containing of 8% silica fume and 2% nano-SiO2, had the highest compressive strength.

Analysis of mechanical and microstructural properties of high performance concretes containing nanosilica and silica fume

The use of nanomaterials in concrete has shown promise, and the use of several types in cementitious compounds has been found to guarantee greater physical–mechanical properties and improvements in microstructure. The use of mineral admixtures, such as silica fume, ensures the improvement of the interfacial transition zone (ITZ) between aggregate and paste in high-performance concrete (HPC). Thus, this work evaluates the performance of superplasticizer additive with colloidal nanosilica suspension and slurried silica fume with HPC and its macro- and micro-structural properties. The mechanical (i.e., compressive strength and elastic modulus) and microstructural properties via (scanning electron microscopy and X-ray micro tomography) of concretes with 1.5 and 3% nanosilica and 5 and 10% silica fume included in the evaluation methods in this study. The results indicate that, with the use of mineral admixtures, the compressive strength and elastic modulus of concrete increased significantly. The concrete with the use of 10% silica fume and 3% nanosilica resulted in a showed an increased strength over 75% at 28 days. Besides that, for same w/b = 0.35 the elastic modulus increased by 36% compared with the reference concrete. The microstructural investigations show that the nanosilica and silica fume led to a densification of microstructure, which is responsible for the improvement of HPC performance.

Properties of High-Performance Concretes made of Black Sand at High Temperature

To modify high-performance concrete (HPC) fireproofing properties, black sand (BS) was partially substituted as fine aggregate at various levels. This study aims at evaluating the BS reliability in improving HPC durability properties for various construction applications based on its unique heavy minerals. To achieve this, five HPC series blends were setup to substitute fine aggregate independently with BS. Substitution percentages ranged from 15 to 100% with consistent supplementary cementing materials (SCMs) proportion for each gathering. Tests were performed to assess compressive strength before and after fire exposure under various temperatures of 250, 500 and 750 °C at different curing age. Generally, blending FA with BS was better than using SF with BS. Utilizing BS in the range of 15 to 60% as fine aggregate with 10% FA improves HPC fire-insulating properties. Besides, Z1 SEM analysis observed homogenously and compacted HPC microstructure at 250 and 500 °C. Doi: 10.28991/cej-2021-03091634 Full Text: PDF

Synergic Effect of Sugarcane Bagasse Ash Based Cement on High Performance Concrete Properties

High performance concrete (HPC) is produced in this study by utilizing the agriculture industry by-product. The usage of by-product helps to condense the disposal issues, ecological degradation and also makes the production of concrete economical. The raw sugarcane bagasse ash from sugarcane industry is processed to ensure the suitability with the properties of cement to be used in HPC. Sugarcane bagasse ash (SCBA) is used as binder in HPC as an alternative of ordinary Portland cement. The properties of the SCBA have been studied. Investigation were carried out experimentally on M 60 grade of high performance concrete blended with SCBA to assess the workability, strength and durability properties at different ages of curing. Three SCBA blended HPC specimens were tested for each trial and test. Test results indicate improved performance in strength and durability properties up to 15% substitution level of SCBA with ordinary Portland cement.

Effect of partial replacement of Eco sand on high performance concrete

The concrete plays a vibrant role in infrastructural developments. The major dispute of environmental degradation with sources of river sand is been substituted by M sand substantially at faster rate. The efforts to minimize the usage of Portland cement in concrete by other supplementary cementitious materials are also forging to control the environment-related problems. The study involves the behaviour of high performance concrete using partial replacement of cement by silica fume and partial replacement of M sand by Eco sand for M60 grade of concrete. Eco sand is an industrial waste product obtained from the cement industry is utilized as per the gradation analysis to evolve a better waste utilization and management system. The experimental works were conducted to evaluate the mechanical properties of high performance concrete containing cementitious materials of silica fume replaced by cement with 1-5%, M sand replaced by Eco-sand of 15-20%. Super plasticizer also added of about 1% to improve the workability of concrete. The results shows that the compressive strength gradually increased with 25% replacement of Eco sand and the optimal percentage of silica fume replacement identified as 5% by weight. The flexural strength at 28 days shows better for 20% replacement of eco sand than the control mix.

The Influence of Ambient Temperature on High Performance Concrete Properties.

This paper presents the results of tests on high performance concrete (HPC) prepared and cured at various ambient temperatures, ranging from 12 °C to 30 °C (the compressive strength and concrete mix density were also tested at 40 °C). Special attention was paid to maintaining the assumed temperature of the mixture components during its preparation and maintaining the assumed curing temperature. The properties of a fresh concrete mixture (consistency, air content, density) and properties of hardened concrete (density, water absorption, depth of water penetration under pressure, compressive strength, and freeze–thaw durability of hardened concrete) were studied. It has been shown that increased temperature (30 °C) has a significant effect on loss of workability. The studies used the concrete slump test, the flow table test, and the Vebe test. A decrease in the slump and flow diameter and an increase in the Vebe time were observed. It has been shown that an increase in concrete curing temperature causes an increase in early compressive strength. After 3 days of curing, compared with concrete curing at 20 °C, an 18% increase in compressive strength was observed at 40 °C, while concrete curing at 12 °C had a compressive strength which was 11% lower. An increase in temperature lowers the compressive strength after a period longer than 28 days. After two years of curing, concrete curing at 12 °C achieved a compressive strength 13% higher than that of concrete curing at 40 °C. Freeze–thaw performance tests of HPC in the presence of NaCl demonstrated that this concrete showed high freeze–thaw resistance and de-icing materials (surface scaling of this concrete is minimal) regardless of the temperature of the curing process, from 12 °C to 30 °C.

Mechanical Properties of High-Performance Concrete with Guinea Corn Husk Ash as Additive

Consideration on High Performance Concrete (HPC) has risen drastically because of the requirement for application of concrete volume with high strengths for construction work. In this study, the mechanical properties of HPC with Guinea Corn Husk Ash (GCHA) as supplement of cement was investigated. The proportioning of Ordinary Portland Cement (OPC) with GCHA is from 0 - 20%. Design of the concrete mix was done to achieve a characteristic strength of 50 N/mm². The chemical composition of the GCHA was determined using X-ray Fluorescence (XRF) Slump and compacting factor of fresh HPC were determined. Concrete cubes (for compressive strength), beams (for flexural strength) and cylinder (for split tensile strength) samples were cast and cured in water for 7 - 56 days. Density, compressive, flexural, and split tensile strengths were determined on the hardened HPC and were further examined using SEM analysis. Compressive strength at 56 days showed that control and inclusion of 5% GCHA gave strength 56.85 N/mm2 and 57.76 N/mm2, respectively above the designed target strength of 56.56 N/mm2 while inclusion of 10% GCHA met characteristics strength of 50 N/mm2. However, 5% GCHA-concrete had the highest flexural and split tensile strengths at 56 days of curing. Integration of 10% GCHA as replacement of OPC would produce concrete of higher strengths compared to conventional HPC at longer curing age. Based on the SEM results, uniform distribution of filler was obtained at 10% GCHA inclusion. At higher percentage of GCHA, resulting composite presents multiple and distinct grains with possible weak interfaces.

Influence of Washing of Crushed Aggregate on Mechanical Properties of High-Performance Concrete Containing Supplementary Cementitious Materials

The paper compares macromechanical and micromechanical properties of high-performance concrete containing supplementary cementitious materials and basalt aggregate. The aggregate was either a common unprocessed crushed basalt aggregate or crushed basalt aggregate the coarse fractions (4/8 and 8/16 mm) of which were washed by water and dried before use. The observed macro-mechanical properties were compressive strength, tensile strength, elastic modulus and depth of penetration of water under pressure; the paper is focused on the first observed property, which is the basic material characteristic. On the microscale, the thickness of the interfacial transition zone (ITZ) was determined by nanoindentation. The positive influence of supplementary cementitious materials and aggregate washing on compressive strength was confirmed and the correlation between macromechanical and micromechanical characteristics was proved.

Multi-Response Optimization of Post-Fire Residual Properties of High Performance Concrete

This paper presents the results of an extensive experimental program undertaken to optimize compressive strength, ultrasonic pulse velocity (UPV), and abrasion wear of heated high performance concrete using Taguhi method and the utility concept. The design of experiments (DOEs) was first carried out by Taguchi method using a standard L 25(35) orthogonal array of three factors with five materials parameters levels. The factors considered in this context of HPC were: fiber volume fracture, age time and post-heat temp. The prism specimens 60x60x300 mm with various volume fractions were casted, left for different age times (7 day, 28 day, and 56 day) then heated up to 200 °C, 400 °C, and 800 °C for a time of 3hrs then they were subsequently tested in the cooled conditions. Based on the experimental results, the materials parameter responses were analyzed.

Effect of hybrid fibres on the mechanical properties of high performance concrete

Fibre reinforcement is a technique used to provide toughness and ductility to brittle cementitious matrices. Reinforcement of concrete using a single type of fibre could improve the properties to a limited level. A hybrid composite refers to two or more types of fibres that are rationally combined to produce a composite that stems benefits from each of the individual fibres and exhibits a synergetic response. This study intends to illustrate and quantify the mechanical properties of Hybrid Fibre Reinforced Concrete. For this purpose, a reference High Performance Concrete (HPC) of grade M65 with water-binder ratio of 0.34 was used. Specimens of plain concrete mix, HPC with silica fume, Steel Fibre Reinforced High Performance Concrete (SFRHPC) containing only steel fibres, and Hybrid Fibre Reinforced High Performance Concrete (HFRHPC) containing steel fibres and carbon fibres were prepared. Optimum amount of silica fume was taken as 12.5%. The crimped steel fibre was added initially at 0.25%, 0.5%, 0.75%, 1% and 1.25% by weight of concrete and its optimum percentage was found out. Once the optimum dosage of crimped steel fibre was obtained, carbon fibre was used to replace the optimum steel fibre dosage at 25%, 50%, 75% and 100% by volume fraction. Thus an optimum hybrid fibre dosage was obtained. The mechanical properties of the HFRHPC like compressive strength, flexural strength, splitting tensile strength, modulus of elasticity and impact resistance were studied and compared with HPC mix. The results revealed that the addition of steel fibre improved all the mechanical properties of concrete.

Effect of Mineral Aggregates and Chemical Admixtures as Internal Curing Agents on the Mechanical Properties and Durability of High-Performance Concrete

In the present work, the effect of mineral aggregates (pumice stone and expanded clay aggregates) and chemical admixtures (superplasticizers and shrinkage reducing additives) as an alternative internal curing technique was investigated, to improve the properties of high-performance concrete. In the fresh and hardened state, concretes with partial replacements of Portland cement (CPC30R and OPC40C) by pulverized fly ash in combination with the addition of mineral aggregates and chemical admixtures were studied. The physical, mechanical, and durability properties in terms of slump, density, porosity, compressive strength, and permeability to chloride ions were respectively determined. The microstructural analysis was carried out by scanning electronic microscopy. The results highlight the effect of the addition of expanded clay aggregate on the internal curing of the concrete, which allowed developing the maximum compressive strength at 28 days (61 MPa). Meanwhile, the replacement of fine aggregate by 20% of pumice stone allowed developing the maximum compressive strength (52 MPa) in an OPC-based concrete at 180 days. The effectiveness of internal curing to develop higher strength is attributed to control in the porosity and a high water release at a later age. Finally, the lowest permeability value at 90 days (945 C) was found by the substitutions of fine aggregate by 20% of pumice stone saturated with shrinkage reducing admixture into pores and OPC40C by 15% of pulverized fly ash. It might be due to impeded diffusion of chloride ions into cement paste in the vicinity of pulverized fly ash, where the pozzolanic reaction has occurred. The proposed internal curing technology can be considered a real alternative to achieve the expected performance of a high-performance concrete since a concrete with a compressive strength range from 45 to 67 MPa, density range from 2130 to 2310 kg/m3, and exceptional durability (< 2000 C) was effectively developed.

Effect of Fibers on Strength and Elastic Properties of Bagasse Ash Blended HPC Composites

Abstract This article presents the details of an experimental investigation carried out on test specimens to assess the effect of the addition of steel, polypropylene fibers, and hybrid fibers (steel and polypropylene) at a total fiber volume fraction of 1.0 % by volume of concrete on the workability and strength-related properties of high performance concrete (HPC) utilizing bagasse ash. All the fiber-reinforced high performance concrete composites contained 10 % bagasse ash to replace cement. The results of the experimental study show that the addition of bagasse ash enhances the mechanical properties of conventional concrete. The incorporation of steel and polypropylene fibers improved the mechanical properties of bagasse blended HPC at each volume fraction considered in this study. Subsequently, it was observed that the addition of 0.75 % steel and 0.45 % polypropylene fibers significantly improved the strength of concrete. The various combinations of steel and polypropylene fibers are investigated, and among these, the best performance was attained by a mixture that contained 0.85 % steel and 0.15 % polypropylene fiber.