Types Of High Performance Concrete Research Articles

The Effect of Different Curing Temperatures on Properties of Reactive Powder Concrete Reinforced by Micro Steel Fibers

Reactive Powder Concrete (RPC) is a type of high-performance concrete that is known for its exceptional strength and durability also RPC is one of the new composite materials that allow for the most efficient use of materials, which benefits the concrete industry economically. Additionally, it improves environmental sensitivity. The main objective of this paper is the determine some characteristics of RPC, such as (compressive strength and fresh density) after exposure to different curing temperatures (60, 120, and 200) oC for 4 hours due two days. This study involves many variables such as micro steel fibers content with 1% by vol. of reactive powder concrete samples as well as elevated temperature. It was discovered that the optimum temperature that was used after conducting the tests was 60 Celsius, as it gave the best results for the mechanical properties of RPC, which were adopted in the rest of the tests. The value of fresh density increased by about (1.95%) and compressive strength increased by about (33.3%) at 60 oC for the age of 28 days in contrast to the reference mixture.

Reactive powder concrete with steel powder and carbon fibres subjected to different curing conditions

Reactive Powder Concrete (RPC) is a special type of high performance concrete which could be used in special applications for construction of structures like bridges and machine foundations. Generally silica sand is used as fine aggregate in RPC which is costly. An attempt is made in this work to proportion RPC with River sand and steel powder which is a waste from CNC industry. Two types of curing conditions were adopted in this work- Steam curing and autoclaving. compressive strength on RPC was found in the range of 90 MPa − 98 MPa in autoclaving curing technique compared to steam curing in which strength range between 65–80 MPa only with increase in steel powder content. Flexural strength was 5–8 MPa for steam curing and it was 6–9 MPa for autoclave curing. Durability tests like sorptivity and RCPT were also conducted.

A novel development of HPC without cement: Mechanical properties and sustainability evaluation

In the current study, a new type of high-performance concrete (HPC) called HPC-CAS (calcium oxide-activated slag) is presented. The HPC-CAS is made from calcium oxide-activated slag and is reinforced with steel, basalt, and recycled polyethylene terephthalate (PET) fibers to make it less brittle. To assess the mechanical properties of the samples, five mix designs were produced, including HPC, HPC-CAS without reinforcement, and HPC-CAS reinforced with fibers. Compressive, splitting tensile, and flexural strengths were then determined. In addition, the study evaluated the environmental impact of different mix designs using two methods: IMPACT 2002+ and CML baseline 2000. The findings indicate that in HPC-CAS, calcium oxide serves as the activator for slag, resulting in a compressive strength of 105 MPa, which is only 4.54% lower than that of HPC. Notably, incorporating steel and recycled PET fibers addresses the issue of brittle fracture in HPC and HPC-CAS samples, leading to compressive strengths of 121 MPa and 78 MPa, respectively. When compared to samples without fibers, the inclusion of steel, basalt, and recycled PET fibers in HPC-CAS resulted in improved splitting tensile strengths of 159%, 89%, and 55%, respectively. The samples containing steel, basalt, and recycled PET fibers also revealed flexural strengths with 3.68 and 1.20 times, and 31% increase, respectively, as compared to those without fibers. Overall, the incorporation of fibers significantly enhanced the brittle behavior of the HPC-CAS geopolymer matrix. However, it is important to note that the addition of 3% fibers to HPC-CAS resulted in higher environmental impacts in all categories as compared to HPC-CAS without fibers. Furthermore, the embodied carbon footprint associated with the production of HPC-CAS was found to be significantly lower, with a reduction of approximately 61%. Furthermore, when comparing HPC-CAS to HPC, it is evident that HPC-CAS exhibits decreased adverse effects on human health, ecosystem quality, and resource utilization.

Performance of High Early Strength Concrete (HESC) using Different Superplasticizer

High Early Strength Concrete (HESC) is one type of high-performance concrete. HESC production requires high-quality materials and additives, namely chemical admixture type C (superplasticizer) to get high performance. This study aims to obtain a HESC mix design using a superplasticizer with the best performance. The 3 variations of HESC are made by adding a superplasticizer to a mixed concrete with the same dosage but from 3 different manufacturers, namely HESC-1, HESC-2, and HESC-3. Specimens performance consisted of tests for both fresh concrete and hardened concrete. The fresh concrete was tested by the slump, and the hardened concrete was tested by density and compressive strength tested at the age of 12 hours, 14 hours, and 3 days on cylindrical specimens measuring 100 mm x 200 mm which have been cured by water curing. Based on the test results, it was found that the average slump values in HESC-1, HESC-2, and HESC-2 were (cm): 64.0, 69.5, and 70.5. This shows that all HESC specimens are categorized as Self Compacting Concrete. According to the results of the density test on all specimens ranging from 2382 to 2436 kg/m3, all specimens are included in normal-weight concrete. With the initial compressive strength value of HESC at the age of 14 hours in the range of 21.0 to 24.9 Mpa, it can be concluded that all HESC specimens meet the requirements of High Early Strength Concrete, where HESC-3 is the best performance one.

Eccentric behaviour of square CFST columns strengthened using square steel tube and high-performance concrete jackets

The eccentric behaviour of concrete-filled steel tube (CFST) square columns strengthened with square steel tubes and high-performance concrete (HPC) jackets is investigated. Four types of HPC are used for concrete jackets: ordinary concrete (OC), self-stressing concrete (SSC), steel-fibre-reinforced concrete (SFC), and steel-fibre-reinforced self-stressing concrete (SFSSC). The experimental variables include eccentricities, width-to-thickness ratios, strengths of the concrete jacket, initial stresses and volume percentages of the steel fibre. The eccentric behaviours of columns with various types of concrete jackets are carefully addressed through the failure mode, load-lateral deflection curve, load versus strain behaviour, capacity analysis and ductility. Among the three volume percentages of steel fibre (0.6%, 0.9%, 1.2%) investigated in this study, 0.9% is the most suitable for improving the behaviour of retrofitted columns. The columns strengthened with the SFSSC jacket exhibit higher load-bearing capacities than the other three types of HPC jackets with good ductility. Considering the self-stressing and steel fibre effects, the stress–strain curves of various HPC jackets are presented. Subsequently, a finite-element (FE) model for the retrofitted column is established and verified along with the loads carried by each component. A detailed analysis of the load-lateral deflection curve and the interaction and stresses of the four components is performed in three stages. Finally, the load-bearing capacities of the retrofitted columns under eccentric loads calculated fusing the EC4, GB50936 and AISC 360 codes are compared.

PENGARUH PENAMBAHAN SERAT BAJA TERHADAP SIFAT MEKANIS REACTIVE POWDER CONCRETE

As urban growth increase, massive high-rise building construction become a critical solution. In high-rise building, column base may be subjected to very high axial load from the upper stories and may experience very large moment due to the lateral loads. As a result, the column base requires a great deal amount of reinforcement which make it very cramped. In order to prevent honeycomb as the reinforcement gap is narrow yet difficult to provide sufficient vibration during concrete casting, high performance concrete (HPC) may be the solution. One of the HPC innovations is Reactive Powder Concrete (RPC). RPC is a self-compacting type of HPC contains well graded fine and super fine aggregates with cement and pozzolanic material to strengthen the Interfacial Transition Zone (ITZ) between the mortar matrix and fine aggregates. RPC may achieve high compressive strength as the mix uses low water to cement ratio, thus it introduces less void and no coarse aggregates, thus ITZ is stronger. RPC has similar characteristic as concrete, with its brittle behaviour. To avoid the brittle failure of RPC, in this study steel fibers are added into the RPC mixture. This research is conducted to examine the effectiveness of using steel fibers on the mechanical properties of Steel Fiber Reactive Powder Concrete (SFRPC). The steel fiber is aimed to increase ductility of tensile strain hardening condition by its multiple crack-bridging behavior.

Freeze–thaw damage to high-performance concrete with synthetic fibre and fly ash due to ethylene glycol deicer

The major aimed at investigating the mechanism of the freeze–thaw damage to high performance concrete (HPC) under ethylene glycol (EG) deicer. In this study, three types of HPC were prepared, as well as the reference concrete (OPC0). Tests were performed to evaluate the ice-formation pressure (Ip), determine the impact of rapid freeze–thaw cycles, study the microstructure, and evaluate the compression strength of the HPC and OPC0. The results yielded suggested that the Ip and the concentration of the EG solution had a strong linear correlation. The Ip of EG solution decreased with its concentration. The freeze–thaw deterioration of OPC0 in 3.5 wt% EG was greater than that of HPC, and the EG did not come into any chemical reaction with concrete hydration product. In this study, HPC blended with 20 wt% fly ash and 0.1% polypropylene fibre addition showed superior frost resistance. This could provide theoretical guidance for the concrete frost-resistance design.

Durability Characteristics of High Early Strength Concrete

High early strength concrete (HESC) is a type of high performance concrete, which attains its specified strength earlier than normal concrete. This type of concrete is normally used in precast and prestressed concrete industries. Many studies have been performed on the production of high early strength concrete, but information on performance of high early strength concrete in durability tests is limited. This article deals with evaluation of durability index characteristics of high early strength concrete mixtures made with two different cements. Durability index tests such as oxygen permeability, sorptivity, rapid chloride permeability and water absorption tests were performed on three HESC mixtures made with two different cements and compared with a reference concrete. Our results reveal that high early strength concrete using steam curing is better than concrete produced using accelerator. The microstructural studies also revealed that steam-cured concrete is better than accelerator-cured concrete supporting the durability index properties of concretes tested.

Analysis of shear rate inside a concrete truck mixer

In addition to the mixing energy applied to the fresh concrete (i.e. shearing during mixing), the shear history after mixing is also important. This applies especially to binder rich concretes like the different types of high performance concrete (HPC). With this in mind, the shear rate is analyzed inside a drum of a concrete truck mixer. The objective is to better understand the effect of transport of fresh concrete, from the ready mix plant to the building site. The analysis reveals the effect of different drum charge volume and drum rotational speed. Also, the effect of yield stress and plastic viscosity is investigated. The work shows that the shear rate decreases in an exponential manner with increasing drum charge volume. It is also shown that for a given drum speed, the shear rate decreases both with increasing plastic viscosity and yield stress.

Durability of Two Types of HPC at Sulphate Solution Environment

Sulphate attack of concrete and cement composites comprises sulphate ions migration into the material porous space and their following reaction with hydration products in the presence of water. Newly formed compounds initiate filling of porous space and volume expansion. Sulphate corrosion phenomenon still belongs to the main mechanism affecting the durability and service life of concrete structures. This paper deals with the investigation of sulphate resistance of two types of High Performance Concrete (HPC) exposed for 168 days to sodium sulphate water solution and reference environment of distilled water. Corrosive action is monitored at chosen time periods non-destructively, i.e. using measurement of length and mass changes, basic physical characteristics and dynamic moduli. Additionally, destructive tests of mechanical parameters are realised. For samples immersed in distilled water, improvement in mechanical strength is observed for the both studied HPCs. In case of HPC C I containing crushed aggregate, the improvement of mechanical resistivity is observed for samples exposed to sulphate solution for 140 days only. For other researched period of sulphate exposure, mechanical strength decreased in comparison with the reference values. On the other hand, HPC C II exhibited mechanical resistivity to sulphate action in all examined time periods of sulphate solution exposure.

Behavior of Steel Fiber-Reinforced Cementitious Mortar and High-Performance Concrete in Triaxial Loading

A study on the behavior of a steel fiber-reinforced cementitious mortar (SFRCM) in a triaxial compression condition and a comparison of results with those of a common high-performance concrete (HPC) is presented. SFRCM with a high compressive strength seems to be a promising material in civil engineering applications. A series of cylindrical specimens of two types of SFRCM with 1% and 2% volume fraction of steel fiber and one type of HPC were prepared and tested under various confining pressures: 0, 5, 10, 15, and 20 MPa (0.72, 1.45, 2.18, and 2.90 ksi). In general, raising the confinement level increases the peak axial stress and the corresponding strain, while on the other hand this causes the specimens to behave more ductile. According to the results, the addition of steel fiber has meaningfully helped increase energy absorption capacity of the specimens. Finally, empirical equations were derived to predict the peak axial stress and the corresponding strain of the tested materials as a function of confining pressure for tested materials.

Numerical simulation of ductile fiber-reinforced cement-based composite

Strain Hardening Cement-based Composite (SHCC) is a type of High Performance Concrete (HPC) that was developed to overcome the brittleness of conventional concrete. Even though there is no significant compressive strength increase compared to conventional concrete, it exhibits superior behavior in tension. The primary objective of the presented research is to develop a constitutive model that can be used to simulate structural components with SHCC under different types of loading conditions. In particular, the constitutive model must be efficient and robust for large-scale simulations. The proposed model, based on previous research Vorel and Boshoff (2012), for plane stress is outlined and the further focus of this paper is on the mesh objectivity of the model. It is shown to be mesh size independent.

Developing an artificial neural network model to evaluate chloride diffusivity in high performance concrete

Chloride attack is one of the major causes of deterioration of reinforced concrete structures. In order to evaluate chloride behavior in concrete, a reasonable prediction for the diffusion coefficient of chloride ion (Dc), which governs the mechanism of chloride diffusion inside concrete, is basically required. However, it is difficult to obtain chloride diffusion coefficients from experiments due to time and cost limitations. This study focuses on the artificial neural network (ANN) as an alternative approach to evaluate the chloride diffusivity of high performance concrete (HPC). A total of 300 different data of fly ash (FA) and slag (GGBFS) concrete were collected from the literature. Two separate ANN models were developed for two types of HPC. The data used in the ANN model consisted of four input parameters which include W/B ratio, cement content, FA or GGBFS content and curing age. Output parameter is determined as diffusion coefficient of chloride ion. Back propagation (BP) algorithm was employed for the ANN training in which a Tansig function was used as the nonlinear transfer function. Through the comparison of the estimated results from ANN models and experimental data, it was clear that ANN models give high prediction accuracy. In addition, the research results demonstrate that using ANN models to predict chloride diffusion coefficient is practical and beneficial.

Influence of a combination of expansive and shrinkage-reducing admixture on autogenous deformation and self-stress of silica fume high-performance concrete

High-performance concrete (HPC) is characterized by its low water-to-cementitious materials (w/cm) and improved properties but also it exhibits high internal capillary tensile stress because the development of autogenous shrinkage which could result in early-age cracking risk and premature deterioration. Since the use of HPC in structural elements has gained wide acceptance in the last decades, the large magnitude of early-age autogenous strains and stresses has to be mitigated to enhance the durability of concrete structure. In this paper, internal stress development induced during the development of autogenous shrinkage strains, especially at early-age was investigated on three different types of HPC cured with a combination of two shrinkage-compensating admixtures. Binary HPC made with blended cement containing 10% of silica fume (SF) has been used with three different low (w/c + sf) of 0.15, 0.23, and 0.30. Shrinkage-reducing agent (SRA) and an expansive additive (EXA) were combined and added to the HPC mixtures to minimize autogenous shrinkage magnitude. The results indicate that the greater the autogenous shrinkage developed, the higher the induced internal tensile stress. It has been found that for the reference mixes, more than 90% of the ultimate magnitude of both autogenous shrinkage and self-tensile stress was developed during the first 24 h. However, the addition of a combination of SRA and EXA has resulted in a significant reduction and a gradual development of both autogenous shrinkage and self-tensile stress as compared to the rapid development and large magnitude in the reference concretes. Moreover, a high dimensional stability was obtained for the 0.30 and 0.23 HPC mixtures containing the combination of expansive and shrinkage-reducing admixtures. On the other hand, a slight decrease of the compressive, of the splitting tensile strengths and the modulus of elasticity was observed.

Research on Long-Term Expansive Deformation of Steel Fiber Reinforced Expansive Concrete

The inherent low tensile strength and shrinkage result in cracking of concrete under work loads. A new way to improve cracking properties is distributing steel fibers into expansive concrete to form a type of composite which is called steel fiber reinforced expansive concrete. This type of high performance concrete could compensate shrinkage as well as improving crack strength. For this concrete, the key point to ensure high performance and safety of concrete structure is to keep a stable expansive deformation during long-term service. A series of tests were carried out to measure long-term restrained expansive deformations of steel fiber reinforced expansive concrete with ages under various restrictions like steel bars and steel fibers. The test investigated some 3-year specimens. For all specimens, test parameters included 2 ratios of steel bar reinforcement, 4 volume fractions of steel fiber and 4 dosages of expansion admixture. The test results showed that the expansion of concrete decreased with increasing of steel bar reinforcing ratio as well as steel fiber volume fraction. In addition, when being in a lower dosage of expansion admixture, the specimens presented remarkable retraction of the expansive deformation. However, when beyond a certain dosage of expansion admixture, the long-term expansive deformation had less change with ages and almost remained the same with 90-day deformation, namely less losses of deformation. Hence, for steel fiber reinforced expansive concrete, using an appropriate dosage of expansion admixture could meet the requirements of designed strengthening and compensating shrinkage.

Examination of durablity of high performance concrete (hpc) that has been subjected to MgSO 4 and NaCI corrosion against freezing and thawing

In this study, freezing and thawing effect over four different high performance concrete (HPC) (0P15Z “0% Pumice + 15% Zeolite”, 5P10Z, 10P5Z and 15P0Z) which has been waited in three different cure medium (H2O, MgSO4 and NaCI) for two years was examined. For this reason, four type of High Performance Concrete(HPC) was produced to substitute for, instead of cement. The produced concretes was cured in lime saturated water of 23 ± 2°C, 7500 Mg/L MgSO4 and 5% NaCI solutions for two years. Before starting the freezing and thawing cycle over the concretes, ultrasonic pulse velocity values were obtained by 28 days ofcompressive strength. The freezing and thawing experiment over the samples taken out of the cure mediums at the end of two years was made regarding fast freezing - thawing in air from ASTM C 666 standard. At the end of 30 freezing and thawing cycle, concrete compressive strength, weight loss, ultrasonic pulse velocity and durability factor over the samples were determined. The results of the experiment proved that there are important differences in, between values due to mineral admixture type and cure medium. Key words: High performance concrete (HPC), pumice, zeolite, freeze and thaw.

Steel–concrete bond strength of lightweight self-consolidating concrete

The bond behavior of lightweight self-consolidating concrete (LWSCC) must be understood in order to use this type of high performance concrete in structural members. The objective of this research program is to assess the bond behavior of reinforcing steel bars embedded in LWSCC members. Three different classes of LWSCC mixtures were developed with two different types of lightweight aggregates. In addition, one normal weight SCC (NWSCC) was developed and used as a control mixture. A total of twenty four pullout tests were conducted on deformed reinforcing bars with an embedded length of either 100 or 200 mm and the load-slip responses, failure modes and bond strengths of LWSCC and NWSCC were compared. Based on the results of this study, the bond strength of deformed bars for LWSCCs are found to be less (between 16 and 38%) as compared with NWSCC. Under the conditions of equivalent workability properties and compressive strength, bond slip properties were shown to be significantly influenced by the type of lightweight aggregate used. In this study, the use of expanded shale in the production of LWSCC significantly enhanced the pullout strength when compared with lightweight slag aggregate.

Effect of damage on permeability and hygro-thermal behaviour of HPCs at elevated temperatures: Part 2. Numerical analysis

In the Part 1 paper (Gawin, et al. 2005) some experimental results concerning micro-structuralrntests, permeability measurements and stress-strain tests of four types of High Performance Concrete, exposed to elevated temperatures (up to 700oC) are presented and discussed. On the basis of these experimental results parameters of the constitutive relationships describing influence of damage and temperature upon material intrinsic permeability at high temperature were determined. In this paper the effects of various formulations of damage-permeability coupling on results of computer simulations are analysed and compared with the results obtained by means of the previously proposed approach, that does not take into account thernthermo-chemical concrete damage directly. Numerical solutions are obtained using the recently developedrnfully coupled model of hygro-thermal and damage phenomena in concrete at elevated temperatures. Highrntemperature effects are considered by means of temperature and pressure dependence of several material parameters. Based on the mathematical model, the computer code HITECOSP was developed. Materialrnparameters of the model were measured by several European laboratories, which participated in thern?ITECO?research project. A model problem, concerning hygro-thermal behaviour and degradation of a HPC structure during fire, is solved. The influence of two different constitutive descriptions of the concrete permeability changes at high temperature, including thermo-chemical and mechanical damage effects, upon the results of computer simulations is analysed and discussed.

Effect of damage on permeability and hygro-thermal behaviour of HPCs at elevated temperatures: Part 1. Experimental results

This paper presents an analysis of some experimental results concerning micro-structural tests, permeability measurements and strain-stress tests of four types of High-Performance Concrete, exposed to elevated temperatures (up to <TEX>$700^{\circ}C$</TEX>). These experimental results, obtained within the "HITECO" research programme are discussed and interpreted in the context of a recently developed mathematical model of hygro-thermal behaviour and degradation of concrete at high temperature, which is briefly presented in the Part 2 paper (Gawin, et al. 2005). Correlations between concrete permeability and porosity micro-structure, as well as between damage and cracks' volume, are found. An approximate decomposition of the thermally induced material damage into two parts, a chemical one related to cement dehydration process, and a thermal one due to micro-cracks' development caused by thermal strains at micro- and meso-scale, is performed. Constitutive relationships describing influence of temperature and material damage upon its intrinsic permeability at high temperature for 4 types of HPC are deduced. In the Part II of this paper (Gawin, et al. 2005) effect of two different damage-permeability coupling formulations on the results of computer simulations concerning hygro-thermo-mechanical performance of concrete wall during standard fire, is numerically analysed.

Eight-year exploration of shrinkage in high-performance concrete

In this paper, an experimental and analytical exploration on the effect of water–binder ratio (w/b), silica fume and age on autogenous, carbonation, drying and total shrinkage of high-performance concrete (HPC) is outlined. Eight types of HPC were studied. Carbonation, internal relative humidity (RH) and strength were studied on specimens from the same batch of HPC that was used in the studies of shrinkage. The results indicate fairly good correlation between carbonation, shrinkage, w/b and RH. The type and amount of silica fume affected shrinkage.