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1
Singh, Ramanpreet, Gurprit Singh Bath et Manjeet Bansal. « Study of High Strength Concrete Using Microsilica ». International Journal of Emerging Research in Management and Technology 6, no 8 (25 juin 2018) : 414. http://dx.doi.org/10.23956/ijermt.v6i8.174.
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The framework of bridges, buildings, roads etc. need concrete. The concrete which is being used is not able to fulfil the contemporaneous needs. In India High Strength Concrete (HSC) is preferred for manufacturing practices and at the same time High Performance Concrete is used at high level. The properties of HSC are improved like mechanical and durability are improved by using silica fume in concrete. HSC has made the work of construction company more rewarding to design tall, long and light structures. HSC is helpful in designing buildings with good number of floors, wide area bridges and slim structure. The products like fly-ash, copper slag, silica fume etc. are produced by industries which leads to various environmental problems. The experiment on silica was done which stated that no strength is lost in silica-fume concretes. The experiment comprises four levels of silica-fume at the rate of 0%, 5.5%, 8.0%,9.5% and 11.0% which results high strength concrete.
2
Xiao, Robert Y., et Samson Ezekiel. « Constitutive Model for High Strength Concrete (HSC) at Elevated Temperatures ». International Journal of Engineering and Technology 5, no 5 (2013) : 550–55. http://dx.doi.org/10.7763/ijet.2013.v5.616.
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Elbasha, Nuri Mohamed. « LIGHTER HIGH STRENGTH CONCRETE BEAM ». Scientific Journal of Applied Sciences of Sabratha University 2, no 2 (27 septembre 2019) : 17–26. http://dx.doi.org/10.47891/sabujas.v2i2.17-26.
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High strength concrete (HSC) has been used extensively in civil construction projects worldwide because it reduces the cross section and the weight of long construction members. In recent years a marked increase in the use of High Strength Concrete (HSC) has been evident in Australian building construction despite the fact that the current Australian design standard provides no design rules for such a material. Very limited information on the properties of HSC and its design and construction processes are available in Australia, although in recent times many studies have been undertaken to produce material and, more importantly, to determine its characteristic. In the last 20 years there has been extensive research to economically utilize new components to improve the quality of HSC. HSC produces smaller but stronger structural elements with large spaces available. It has been studied that the cost of using HSC instead of Normal Strength Concerete (NSC) in different types of constructions. This proved that structures constructed with HSC are lighter and economical compared with those constructed with NSC. In the long term durability significantly affects project costs. In other words after several years a concrete structure needs rehabilitation or in critical cases must be demolished, therefore the price of a project consists of initial costs plus those covering any rehabilitation. A huge amount of money could be saved by utilizing the durability characteristics of high strength concrete. This study presents recent information and the benefits of high strength concrete. Also, provides in brief an experimental proof that installing a helix with a suitable pitch and diameter in the compression zone of beams significantly enhances their strength and ductility. Therefore, designers could confidently use high-strength concrete and helical confinement to design long and light reinforced concrete beams.
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Chen, Xiao Bo, Jian Yin et Wei Min Song. « Autogenous Volume Deformation and Creep Properties Analysis of C60 High Performance Concrete and C60 High Strength Concrete ». Advanced Materials Research 639-640 (janvier 2013) : 364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.639-640.364.
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Based on engineering practice, autogenous volume deformation and creep properties of C60 high performance concrete(C60 HPC) and C60 high strength concrete(C60 HSC) were evaluated in the study. The results showed that the cement partly-replaced with fly ash could significantly decrease the creep deformation, creep coefficient and creep degree. In comparison with C60 HSC, the creep coefficient and creep degree of C60 HPC were decreased 17.9％and15.8％ in 28 days, 22.9% and 21.0% in 270 days. For C60 HPC and C60 HSC at the same age, autogenous volume deformation of C60 HPC is greater than that of C60 HSC, but they were both less than 80×10-6 , and the autogenous volume deformation was basically completed in 7 days.
5
Lu, Zhao Hui, Yan Gang Zhao et Zhi Wu Yu. « Strain of High-Strength Concrete at Peak Compressive Strength ». Advanced Materials Research 446-449 (janvier 2012) : 161–65. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.161.
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The paper discusses the strain of high-strength concrete (HSC) at peak compressive strength for a wide range of compressive strength. A large volume of selected experimental data has been collected from existing literature and then analyzed. Particular emphasis has been given to studying the effects of concrete compressive strength and the types of coarse aggregate on the strain of HSC at peak compressive strength. The adequacy and applicability of the existing models for predicting the strain of HSC at peak compressive strength has been critically examined, and a new empirical model is proposed to cover concrete strength up to 125 MPa. The new empirical model seems to perform much better when applied to the published experimental data on normal weight concrete over a wide strength range.
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Srikanth, Sreddy. « Durability Studies on High Strength Concrete ». Pakistan Journal of Scientific Research 2, no 1 (30 juin 2022) : 17–21. http://dx.doi.org/10.57041/pjosr.v2i1.22.
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High strength concrete (HSC) is very useful for recent construction technology; the major problem of HSC is the insufficient ductility. To investigate the ductility of HSC, the entire stress-strain curve, especially in the descending branch, shall be recorded. The aim of this study is to investigate the durability of High strength concrete for different replacement levels of mineral admixtures by alternate wetting and drying phenomenon which includes; acid attack, sulphate resistance and marine Environment and also to determine the compressive strength of concrete as GGBFS partial replacement for cement. Concrete mix is designed for M80 Grade of concrete using modified ACI method. Maximum Compressive Strength of 96.4MPa and 91.6 MPa at 28days were found for the HSC specimens at a partial replacement of cement with 30% of GGBFS in normal water curing and accelerated curing tank respectively. The specimens immersed in marine solution were found to have less weight loss when compared to acids and sulphate solution.
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Vasilenko, Anastasia, Dmitry Chernogorsky, Dmitry Strakhov et Leonid Sinyakov. « High-strength concrete eccentrically compressed elements ». E3S Web of Conferences 140 (2019) : 02017. http://dx.doi.org/10.1051/e3sconf/201914002017.
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The article is devoted to the analysis of technical and economic efficiency of application of high-strength concrete (HSC) in the eccentrically compressed columns. In the first part of the paper, the effect of concrete grade on in-creasing the column stiffness depending on steel ratio at different values of the relative eccentricity is considered. According to the results of the calculation, application of HSC is most effective at low values of the relative ec-centricity because increasing the concrete strength leads to more intensive increasing of column stiffness than increasing of steel ratio. In the second part of the paper, the material cost of the 1 linear meter of the column is calculated at the fixed value of column stiffness and application domain of HSC is defined in the case under consideration. In addition, load characteristics providing the efficiency of HSC application in the eccentrically compressed columns are determined.
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Elsanadedy, Hussein M. « Residual Compressive Strength of High-Strength Concrete Exposed to Elevated Temperatures ». Advances in Materials Science and Engineering 2019 (28 mai 2019) : 1–22. http://dx.doi.org/10.1155/2019/6039571.
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High-strength concrete (HSC) has several well-known technical, aesthetic, and economic advantages over normal-strength concrete (NSC), which explains the increasing popularity of the former material in the construction domain. As in the case of NSC, however, high temperature adversely affects HSC mechanical properties even more than in NSC, as indicated by the many studies performed so far on HSC at high temperature (hot properties) or past a thermal cycle at high temperature (residual properties). Since many code provisions concerning concrete properties versus high temperature were developed for ordinary concrete and the available models (in terms of stress-strain relationship) come mostly from the tests on NSC—as the tests on HSC are less numerous—developing predictive relationships for HSC exposed to high temperature is still an open issue, especially with reference to many parameters affecting concrete compressive strength, like temperature as such, heating rate, water-to-binder ratio, and strength in compression, to cite the most relevant parameters. To this purpose, a large database (more than 600 tests) is examined in this paper, which is focused on HSC residual properties and on the variables affecting its residual strength. Available design models from various guidelines, standards, codes, and technical reports are tested against the database, and new regression-based models and design formulae are proposed for HSC strength in compression, after the exposure to high temperature.
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Vincent, Thomas, et Togay Ozbakkloglu. « An Experimental Study on the Compressive Behavior of CFRP-Confined High- and Ultra High-Strength Concrete ». Advanced Materials Research 671-674 (mars 2013) : 1860–64. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.1860.
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It is well established that external confinement of concrete with fiber reinforced polymer (FRP) sheets results in significant improvements on the axial compressive behavior of concrete. This understanding has led to a large number of experimental studies being conducted over the last two decades. However, the majority of these studies have focused on normal strength concretes (NSC) with compressive strengths lower than 55 MPa, and studies on higher strength concretes have been very limited. This paper presents the results of an experimental study on the compressive behavior of FRP confined high- and ultra high-strength concrete (HSC and UHSC) with average compressive strengths of 65 and 100 MPa. A total of 29 specimens were tested under axial compression to investigate the influence of key parameters such as concrete strength and method of confinement. All specimens were cylindrical, confined with carbon FRP and were 305 mm in height and 152 mm in diameter. Results obtained from the laboratory testing were graphically presented in the form of axial stress-strain relationships and key experimental outcomes are discussed. The results of this experimental study indicate that above a certain confinement threshold, FRP-confined HSC and UHSC exhibit highly ductile behavior. The results also indicate that FRP-wrapped specimens perform similar to concrete-filled FRP tube (CFFT) specimens at ultimate condition, however notable differences are evident at the transition region when comparing stress-strain curves.
10
Yang, In-Hwan, Changbin Joh et Kyoung-Chul Kim. « A Comparative Experimental Study on the Flexural Behavior of High-Strength Fiber-Reinforced Concrete and High-Strength Concrete Beams ». Advances in Materials Science and Engineering 2018 (4 septembre 2018) : 1–13. http://dx.doi.org/10.1155/2018/7390798.
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The flexural responses of high-strength fiber-reinforced concrete (HSFRC) beams and high-strength concrete (HSC) beams are compared in this study. A series of HSFRC and HSC beams were tested under pure flexural loading. The effects of the type of concrete, compressive strength of the concrete, and tensile rebar ratio on the flexural behavior of the concrete beams were investigated. The flexural behavior of the HSFRC and HSC beams including the induced crack and failure patterns, load and deflection capacity, crack stiffness, ductility index, and flexural toughness was compared. The crack stiffness of the HSC and HSFRC beams increased with the rebar ratio. For the same rebar ratios, the crack stiffness of the HSFRC beams was much greater than that of the HSC beams. The ductility index of the HSC beams decreased sharply with an increase in the rebar ratio, but the ductility index of the HSFRC beams did not show a clear decrease with increasing rebar ratio. The flexural toughness of the HSFRC beams was greater than that of the HSC beams at higher rebar ratios of 1.47% and 1.97%, indicating that the energy absorption of the HSFRC beams was greater than that of the HSC beams. Test results also indicated that HSFRC developed better and more consistent ductility with higher rebar ratio. In addition, the tested bending strength and sectional analysis results were compared.
11
Zeyad, A. M., Bassam A. Tayeh, Abdalla M. Saba et M. A. Megat Johari. « Workability, Setting Time and Strength of High-Strength Concrete Containing High Volume of Palm Oil Fuel Ash ». Open Civil Engineering Journal 12, no 1 (16 mars 2018) : 35–46. http://dx.doi.org/10.2174/1874149501812010035.
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Introduction: Palm oil fuel ash in two various forms-ground (GPOFA) by heat-treated carbon-free ultrafine of a median particle size of 2 μm (UPOFA) were utilized to produce high strength concretes (HSC-GPOFA (HSCgx), HSC-UPOFA (HSCux), and HSC-OPC) at different levels ordinary Portland cement (OPC) partial replacements (x) of 20, 40 and 60%. Methods: The workability (slump, slump loss, and compacting factor), initial and final setting times and strength in both forms of concrete were investigated. Results and Conclusion: The results showed that HSCu had improved physical properties and chemical compositions, extended setting times, enhanced workability, better strength, and enhanced workability retention compared to HSCg and HSC-OPC. Further, POFA carbon content negatively influenced the workability and setting time, while its specific gravity had a positive influence due to the enhancement of paste volume and particles lubrication effects. However, carbon content and surface areas of POFA did not significantly influence the compressive strength of HSC at the level of partial OPC substitution not exceeding 40%.
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Yang, In-Hwan, Jihun Park, Nhien Dinh Le et Sanghwa Jung. « Strength Properties of High-Strength Concrete Containing Coal Bottom Ash as a Replacement of Aggregates ». Advances in Materials Science and Engineering 2020 (23 juin 2020) : 1–12. http://dx.doi.org/10.1155/2020/4246396.
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Most previous studies on the strength properties of coal bottom ash (CBA) concrete have focused on concrete with a normal compressive strength, and thus, studies on the strength properties of high-strength concrete (HSC) containing CBA are limited. Therefore, the effects of replacing fine aggregates with CBA and variations in the curing age on the strength properties of HSC with a compressive strength of greater than 60 MPa were investigated in this study. The different CBA contents included 25, 50, 75, and 100%, and the different curing ages were 28 and 56 days. The mechanical properties of the HSC with CBA incorporated as fine aggregates were examined. The experimental results revealed that CBA could be partially or totally substituted for fine aggregates during HSC production. The test results also showed that the compressive, splitting tensile, and flexural strengths of the HSC containing CBA fine aggregates slightly decreased as the CBA content increased. Moreover, useful relationships between the compressive strength, splitting tensile strength, and flexural strength were suggested, and the predictions reasonably agreed with the measurements. Compared to those of the control specimen, the pulse velocities of the HSC specimens at various CBA contents decreased by less than 3%. In addition, equations for predicting the strength values of CBA concrete by using the ultrasonic pulse velocity were suggested.
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Araújo, Rafael Campos de Alencar, William Menezes da Silva, Tiago Ancelmo de Carvalho Pires et José Jéferson do Rêgo Silva. « Compressive strength assessment of high strength concrete after fire using ultrasonic test method ». Research, Society and Development 11, no 11 (15 août 2022) : e63111132719. http://dx.doi.org/10.33448/rsd-v11i11.32719.
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This paper aims to evaluate the non-destructive ultrasonic pulse velocity (UPV) test method for determining the compressive strength of high strength of concrete (HSC) after fire. The compressive strength was determined through destructive cylinder test and by measuring ultrasonic pulse velocity. A total of 10 equations that relate compressive strength of concrete to UPV were evaluated in a total of 20 concrete samples. None of the equations were well suited for the case of HSC. The paper proposed a new equation and the UPV test showed suitable to assessment post-fire damaged HSC.
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Elbasha, Nuri Mohamed. « Reinforced HSC Beams ». Key Engineering Materials 629-630 (octobre 2014) : 544–50. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.544.
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The primary long and short term advantages of high strength concrete are, low creep and shrinkage, higher stiffness, higher elastic modulus, higher tensile strength, higher durability (resistance to chemical attacks) and higher shear resistance. In addition, high strength concrete reduces the size of the member, which in turn reduces the form size, concrete volume, construction time, labor costs and dead load. Reducing the dead load reduces the number and size of the beams, columns and foundations. Thus there is a positive impact on reduction of maintenance and repair costs and an increase in rentable space. Other, yet to be discovered advantages may also exist. High strength concrete has definite advantages over normal strength concrete. The ductility of over reinforced HSC beams is enhanced through the application of helical reinforcement located in the compression region. The pitch of helix is an important parameter controlling the level of strength and ductility enhancement. This paper presents an experimental investigation of the effect of helices on the behavior of over reinforced high strength concrete beams through testing ten helically confined full scale beams. The helix pitches were 25, 50, 75, 100 and 160 mm. Beams’ cross section was 200×300 mm, and with a length of 4 m and a clear span of 3.6 m subjected to four point loading. The main results indicate that helix effectiveness is negligible when the helical pitch is 160 mm (helix diameter). The experimental program in this study proved that the HSC, HSS and helical confinement construct a reinforced concrete beam. This beam has the ability to resist weathering action and chemical attack while maintaining its desired engineering properties. In near future Reinforced High Strength Concrete Beam with Helical Confinement will be considered as a durable and sustainable Reinforced Concrete Beam.
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Křížová, Klára, Martin Ťažký, Milan Meruňka et Ondřej Pikna. « Study of High Strength Concretes with Variability of Composition Designs ». Solid State Phenomena 325 (11 octobre 2021) : 156–61. http://dx.doi.org/10.4028/www.scientific.net/ssp.325.156.
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High Strength Concretes (HSC) are concretes defined mainly by compressive strength. The strength of concrete can guarantee other excellent results of properties, namely durability. Essential for the production of HSC is a careful approach to the design of concrete composition, especially the quality of raw materials. It is primarily necessary to increase the content of the binder combined mainly with Portland cement and another admixture. Due to its excellent properties, Silica fume is largely used as an admixture, where it is necessary to consider its effective amount. It is also suitable to combine this admixture with other types of active admixtures. The question of the type of coarse aggregate fractions used is crucial. The quality and purity of aggregates is an essential part of the quality design of these concretes, influencing practically all the resulting parameters of concrete. The article presents a set of tests on designed High strength Concretes, differing in the composition of the concrete to demonstrate the variability of the design concept and its effect on the resulting values of strength and durability.
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Liu, Feng, Jiang Zhu, Zhou Li Wen et Li Juan Li. « Performance of Polypropylene Fiber and Rubber Powder Improved High Strength Concrete ». Key Engineering Materials 400-402 (octobre 2008) : 403–8. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.403.
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Based on high strength concrete (HSC), the improved HSC concrete was produced by adding different contents of fine grain rubber particles and polypropylene fibers. The grain size of the rubber particle is 420 m and the rubber content is 1%, 2%, and 3% of the mass of cementitious material respectively. The volume fraction of polypropylene fiber is 0.1%.The performance of HSC, rubber particle improved high strength concrete (RHSC), polypropylene fiber improved high strength concrete (PHSC) and polypropylene fiber hybrid rubber particle improved high strength concrete (PRHSC) before and after high temperature are studied. The investigation methods used are the external surface inspection, weight loss and residual strength testing. The experimental results show that rubber particles can improve the workability of HSC and PHSC under normal temperature. Polypropylene fiber can significantly improve the spalling failure resistance property of HSC and RHSC.
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Xiao, Jian Zhuang, Qing Hai Xie, Yi Zhao Hou et Zhi Wei Li. « Reliability Analysis of High-Strength Concrete Columns during a Fire ». Key Engineering Materials 629-630 (octobre 2014) : 273–78. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.273.
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A reliability analysis was conducted on high-strength concrete (HSC) columns during a fire. The influences of fire’s randomness and explosive spalling of concrete were investigated. The fire resistance for axial loading capacity of HSC columns was in terms of steel yield strength and concrete compressive strength with considering the effect of elevated temperatures. The load random variables included dead load and sustained live load. The JC method was applied to calculate the reliability index of the fire resistance of axially loaded HSC columns. It was found that the randomness of fire and explosive spalling of concrete had a significant influence on reliability of HSC columns.
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Newman, Aidan, Nuradila Izzaty Halim, Muhd Norhasri Muhd Sidek, Hamidah Mohd Saman et Anizahyati Alisibramulisi. « Enhancement of High Strength Concrete Performance By Utilising Nano Waste Paper Sludge Ash ». Scientific Research Journal 18, no 2 (1 septembre 2021) : 89–101. http://dx.doi.org/10.24191/srj.v18i2.11398.
Texte intégralRésumé :
High strength concrete (HSC) is an amazing breakthrough in the history of construction material. Due to its high strength, durability, and economic value, it has been used in large-scale construction with a unique structure design not achievable by conventional concrete. However, HSC uses a high amount of cement powder which contributes to its overall strength. However, it will require high cement consumption and increases carbon dioxide emission. Waste paper sludge ash (WPSA) is utilised in cement and has improved concrete properties. Nano engineered WPSA might further enhance HSC capabilities. This research focused on the physical and fresh properties of HSC with partial replacement of nano-engineered WPSA to cement through experimental investigation. The HSC produced in this research has a targeted strength of more than 40MPa with a fixed water-cement ratio of 0.2. The WPSA was oven-dried and was sieved to a particle size of 212 micrometers. Then, it was milled until a nano-size particle is obtained. The nano WPSA is used to replace cement in the HSC mix with a replacement percentage of 1%, 3%, 5%, 7%, and 10%. The new properties of the concrete were measured by conducting the flow table test, and the physical property was determined by conducting the compressive test. Compressive tests were conducted for 1, 3, 7, 14, and 28 days with a cube sample size of 50mm x 50mm x 50mm. This research shows that 1% of nano WPSA replacement tends to improve the compressive strength of the HSC concrete by 10.7% compared to the control sample. On the other hand, the 1% replacement of nano WPSA in HSC did not affect the concrete's workability compared to the control sample. The conventional HSC properties were improved with less usage of cement with the use of WPSA.
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Chen, Bo, Yue Bo Cai, Jian Tong Ding et Yao Jian. « Crack Resistance Evaluating of HSC Based on Thermal Stress Testing ». Advanced Materials Research 168-170 (décembre 2010) : 716–20. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.716.
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In order to evaluate the crack resistance of high strength fly ash concrete, concretes with different contents of silica fume and fly ash were compared with same strength grade by adjusting water to binder ratio. Compared with the concrete with 5% silica fume plus 35% fly ash，concrete with 40% fly ash has same mechanical properties and tensile strain as well as lower drying shrinkage. Complex crack resistance of high strength fly ash concretes were evaluated by Temperature Stress Testing Machine (TSTM). The results show that fly ash concretes have outstanding crack resistance because of higher allowable temperature differential and lower cracking temperature.
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Lim, Jian Chin, et Togay Ozbakkloglu. « A Simple Design-Oriented Model for FRP-Confined High-Strength Concrete ». Advanced Materials Research 743 (août 2013) : 45–49. http://dx.doi.org/10.4028/www.scientific.net/amr.743.45.
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This paper presents a study on the axial compressive behavior of fiber reinforced polymer (FRP)-confined high-strength concrete (HSC). A large experimental test database assembled from the published literature was used to investigate and quantify factors influencing the compressive behavior of FRP-confined HSC. The database consisted of 976 test data having unconfined concrete strength ranging from 6.2 to 169.7MPa. Based on the analysis results of the database, it was found that the threshold confinement stiffness increases significantly with an increase in concrete strength, which in turn adversely affects the strength enhancement of confined concrete. It was also observed that the hoop rupture strain of FRP shell decreases with an increase in concrete strength. Existing confinement models that are applicable to FRP-confined HSC were assessed using the database. Finally, a new simple design-oriented model for FRP-confined HSC developed on the basis of the database is presented.
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Luan, Shu Guang, Rui Jin Zhang et Hao Wang. « Research on the Mechanical Behavior of High Strength Concrete ». Advanced Materials Research 243-249 (mai 2011) : 1047–52. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.1047.
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Bases on experimental investigations of HSC and NSC, HSC’s mechanical behavior, failure mechanism, fracture toughness, characteristic length and damage feature are discussed in the paper, and the formula for flexural strength and comparative toughness is given. The results show that the HSC has a good uniformity of structural entity and large cracking resistance. In addition, HSC is more brittle and more vulnerable to damage than NSC.
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Nuruddin, Muhd Fadhil, Sadaqat Ullah Khan et Nasir Shafiq. « Effect of Calcined Kaolin on the Mechanical Properties of High-Strength Concrete as Cement Replacing Material ». Applied Mechanics and Materials 567 (juin 2014) : 375–80. http://dx.doi.org/10.4028/www.scientific.net/amm.567.375.
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Locally available kaolin has been calcined and used as cement replacing material (CRM) in High-strength concrete (HSC). Total five (05) mixes of concrete have been examined using calcined kaolin (CK) of 0, 5, 10, 15 and 20% by weight of cement. For each mix, compressive strength, splitting tensile strength and flexural strength have been determined by preparing three specimens. The effect of CK on the mechanical properties of HSC has been investigated at age of 7, 28, 56 and 90 days. Multiple linear regressions through least square error have been used to develop the expression and to predict the compressive, splitting tensile strengths and flexural strength of HSC. It has been found that CK as CRM increases the strength significantly. The models may predict the strengths closely match the measurements and optimum replacement of cement by CK.
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Emad Yassin Khudhair. « Repaired Reinforced Concrete Beams with Normal and High Strength Concrete ». Diyala Journal of Engineering Sciences 6, no 2 (1 juin 2013) : 21–37. http://dx.doi.org/10.24237/djes.2013.06203.
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In resent years several attempts were undertaken to repair damaged reinforced concrete structures. Studies on the effectiveness of repaired and strengthened reinforced concrete elements which fail primarily due to formation of major flexural cracks are same what limited for normal strength concrete (NSC) and very limited for high strength concrete (HSC). The overall objective of the present work is to investigate the strength and deformation characteristics in flexure of reinforced HSC and NSC beams repaired with either with concrete alone or with fiber reinforced concrete or with Welded Wire Mesh (W.W.M). From the results obtained, it was found that the beams were adequately repaired and the general mode of failure was flexural. The repaired beams had higher strength than the original beams. All repaired beams exhibited significant decrease in deflection than the original beams.
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Shi, Qing Xuan, Yuan Tian et Wei Hou. « Experimental Study of Shear Behavior of High-Strength Concrete Beams with High-Strength Stirrups ». Advanced Materials Research 163-167 (décembre 2010) : 972–76. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.972.
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This paper presents an experimental study of shear behavior of simply supported HSC beams reinforced with high-strength stirrups under monotonic concentrated loading. Six specimens with 150×300 mm square cross section were tested. The effects of three variables such as the stirrup ratio, stirrup yield strength and average confining stress are studied. Based on test results, the shear behavior of HSC beams with high-strength stirrups was evaluated. Combined with other test results, shear strength measured in test are compared with the values calculated according to the expressions proposed in this paper and in Code for design of concrete structures of China (GB 50010-2002). The study concludes that shear capacity is sparingly estimated by the Code for design of concrete structures of China (GB 50010-2002) when the average confining stress below 3MPa, but it is emphasis on insecurity when the average confining stress exceeds 3MPa. The empirical equation proposed in this paper for predicting the shear strength of HSC beams with high-strength stirrups is appropriate.
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Ahmad, Waqas, Syed Hassan Farooq, Muhammad Usman, Mehran Khan, Ayaz Ahmad, Fahid Aslam, Rayed Al Yousef, Hisham Al Abduljabbar et Muhammad Sufian. « Effect of Coconut Fiber Length and Content on Properties of High Strength Concrete ». Materials 13, no 5 (28 février 2020) : 1075. http://dx.doi.org/10.3390/ma13051075.
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Recently, the addition of natural fibers to high strength concrete (HSC) has been of great interest in the field of construction materials. Compared to artificial fibers, natural fibers are cheap and locally available. Among all natural fibers, coconut fibers have the greatest known toughness. In this work, the mechanical properties of coconut fiber reinforced high strength concrete (CFR-HSC) are explored. Silica fume (10% by mass) and super plasticizer (1% by mass) are also added to the CFR-HSC. The influence of 25 mm-, 50 mm-, and 75 mm-long coconut fibers and 0.5%, 1%, 1.5%, and 2% contents by mass is investigated. The microstructure of CFR-HSC is studied using scanning electron microscopy (SEM). The experimental results revealed that CFR-HSC has improved compressive, splitting-tensile, and flexural strengths, and energy absorption and toughness indices compared to HSC. The overall best results are obtained for the CFR-HSC having 50 mm long coconut fibers with 1.5% content by cement mass.
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Sadowska-Buraczewska, Barbara, Danuta Barnat-Hunek et Małgorzata Szafraniec. « Influence of Recycled High-Performance Aggregate on Deformation and Load-Carrying Capacity of Reinforced Concrete Beams ». Materials 13, no 1 (2 janvier 2020) : 186. http://dx.doi.org/10.3390/ma13010186.
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The use of recycled concrete aggregates (RCA) in high performance concrete (HPC) was analyzed. The paper presents the experimental studies of model reinforced concrete beams with a rectangular section using high-performance recycled aggregates. Two variable contents of recycled aggregate concrete were used in this study: 50% and 100%. The experimental analyses conducted as immediate studies concerned the following issues: short time loads-deflection, load-carrying capacity of beams, deformation of concrete, cracks, and long-term loads-deflection. The comparative analysis involves the behavior of beams made of high performance concrete-high strength concrete (HPC-HSC) recycled aggregates with model control elements made of regular concrete based on natural aggregates. The deflection values for the recycled aggregate beams were 20% higher than in the case of the control beams made of HPC-HSC exclusively. Replacement of aggregate with recycled concrete aggregate resulted in a large decrease in the value of these two parameters, i.e., compression strength by about 42% and modulus of elasticity by about 33%.
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Lei, Xiao, Rui Wang, Hanwan Jiang, Faxiang Xie et Yanni Bao. « Effect of Internal Curing with Superabsorbent Polymers on Bond Behavior of High-Strength Concrete ». Advances in Materials Science and Engineering 2020 (30 décembre 2020) : 1–13. http://dx.doi.org/10.1155/2020/6651452.
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High-strength concrete (HSC) is widely used in engineering due to its high strength and durability. However, because of its low water-to-cement ratio, external curing water hardly enters the dense internal structure of HSC so that high self-desiccation shrinkage often takes place. As a result, superabsorbent polymers (SAP) are added as an internal curing material to effectively reduce the shrinkage of high-performance concrete. Meanwhile, the bond performance between reinforcing steel and SAP HSC concrete remains unknown. In this paper, the bond performance of HSC mixed with SAP is studied by pull-out tests, and the results were obtained as follows: (1) the bond strength of HSC mixed with SAP increased first and then decreased with the increase of SAP content; (2) the slip at ultimate bond strength of HSC with SAP decreased with the increase of compressive strength; (3) a prediction model of the stress-slip relationship between steel rebars and HSC was established.
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Long, Koh Sin, Mudiono Kasmuri, Abu Sufian Zia Hasan et Roszilah Hamid. « Dynamic Increase Factor of High Strength Concrete with Silica Fume at High Strain Rate Loading ». Materials Science Forum 857 (mai 2016) : 299–304. http://dx.doi.org/10.4028/www.scientific.net/msf.857.299.
Texte intégralRésumé :
The dynamic mechanical properties (stress-strain diagram, ultimate stress, ultimate strain and strain rate) and of high strength concrete (HSC) with 5% and 10% silica fume (SF) addition at high strain rate of 10 s-1 to 102 s-1 (3.8 MPa, 4.1 MPa and 4.8 MPa) are determined using Split Hopkinson Pressure Bar equipment. The compressive strength of the HSC at design strength of 80 and 90 MPa is also determined. Results show that the compressive strength of the 5%SF and 10%SF HSC are 83 MPa and 92 MPa, respectively. The dynamic stress-strain diagrams show that the higher the pressure load, the higher the values of ultimate dynamic stress, σu and the ultimate strain rate, ἐu for both percentages of SF addition concrete. The ultimate dynamic stress, σu are between 200 – 250 Mpa and the ultimate strain rate, ἐu is in the range of 95 s-1 and 160 s-1. The ultimate dynamic strain, εu between 0.005-0.008 mm/mm. The dynamic increase factors (DIF) of the HSC are more than 2 compare to normal strength concrete.
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Shui, Zhong He, Jun Jie Zeng, Yang Liao et Zheng Leng. « Influence of Metakaolin on Strength and Microstructure of High-Strength Concrete ». Key Engineering Materials 509 (avril 2012) : 33–39. http://dx.doi.org/10.4028/www.scientific.net/kem.509.33.
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Concrete with a compressive strength of 100MPa was produced with metakaolin(MK), and the effect of MK replacement levels on compressive strength of concrete with a water to binder ratio of 0.25 was studied in this paper. XRD, microhardness tests, SEM and MIP were used to investigate the influences of MK on the phase composition, microhardness of interfacial transition zone(ITZ), microstructural morphology and pore structure of the high-strength concrete (HSC). The results showed that the incorporation of MK promoted the hydration process and decreased the amount of Ca(OH)2 crystals. Furthermore, MK increased the ITZ microhardness of HSC, enhanced the hydrates and improved the bond performance of aggregate and paste. The weak zone between aggregate and paste became almost disappeared when 10% MK was blended. Meanwhile, refinement of the concrete pore structure was obtained in the presence of MK. The improvement of strength and microstructure became more obvious as the MK replacement level increased to 15%.
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Ding, Hui, Jian Ping Wang et Li Song. « Numerical Test Research on High-Strength Concrete Square Columns with High-Strength Aseismic Transverse Reinforcement under Concentric Compression ». Advanced Materials Research 1120-1121 (juillet 2015) : 1475–79. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.1475.
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This paper focuses on the the relationship between strength and ductility of high-strength concrete (HSC) columns with high-strength aseismic transverse reinforcement under concentric compression and its influencing factors. Some confining models for HSC with high-strength aseismic transverse reinforcement are introduced. Based on 10 groups of high-strength aseismic stirrup confined high-strength concrete square columns are tested under concentric compression, the influence of stirrup in binding strength and the ductility of concrete columns on different stirrup strength, different volume ratio of reinforcement, different stirrups type and different stirrup spacing form is studied by using finite element software ABAQUS. The results indicate that a good agreement is obtained between calculated results and experimental ones. The high-strength stirrup confined concrete columns can improve the bearing capacity and deformation performance of components effectively, laying the foundation of the applications of high-strength stirrups in concrete structures.
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Dean, SW, M. Ekenel et JJ Myers. « Durability Performance of Bridge Concretes, Part II : High-Strength Concrete (HSC) ». Journal of ASTM International 2, no 7 (2005) : 14019. http://dx.doi.org/10.1520/jai14019.
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Barbosa, M. B., A. M. PEREIRA, J. L. Akasaki, C. F. Fioriti, J. V. Fazzan, M. M. TASHIMA, J. J. P. Bernabeu et J. L. P. Melges. « Impact strength and abrasion resistance of high strength concrete with rice husk ash and rubber tires ». Revista IBRACON de Estruturas e Materiais 6, no 5 (octobre 2013) : 811–20. http://dx.doi.org/10.1590/s1983-41952013000500007.
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The paper discusses the application of High Strength Concrete (HSC) technology for concrete production with the incorporation of Rice Husk Ash (RHA) residues by replacing a bulk of the material caking and rubber tires with partial aggregate volume, assessing their influence on the mechanical properties and durability. For concrete with RHA and rubber, it was possible to reduce the brittleness by increasing the energy absorbing capacity. With respect to abrasion, the RHA and rubber concretes showed lower mass loss than the concrete without residues, indicating that this material is attractive to be used in paving. It is thus hoped that these residues may represent a technological and ecological alternative for the production of concrete in construction works.
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Vincent, Thomas, et Togay Ozbakkloglu. « Axial Compressive Behavior of High- and Ultra High-Strength Concrete-Filled AFRP Tubes ». Advanced Materials Research 671-674 (mars 2013) : 626–31. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.626.
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Concrete-filled FRP tubes (CFFTs) have received significant research attention over the last two decades. However, the experimental studies on the behavior of CFFTs filled with high- and ultra high-strength concretes (HSC and UHSC) remain very limited. This paper presents the results of an experimental study on the compressive behavior of circular HSC- and UHSC-filled fiber reinforced polymer (FRP) tubes (HSCFFTs and UHSCFFTs). A total of 24 aramid fiber made CFFTs were tested under uniaxial compression to investigate the influences of concrete strength, amount of confinement and manufacturing method of FRP tubes. The influence of tube manufacturing method was investigated with specimens manufactured with either automated filament winding or manual wet lay-up techniques. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the manufacturing method of the FRP tubes significantly influence the compressive behavior of CFFTs.
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Mohammed, Ihtesham Hussain, Ahmed Majid Salim Al Aamri, Shakila Javed et Yahya Ubaid Al Shamsi. « A Comparative Investigation on Normal and High Strength Concrete Beams under Torsion ». Materials Science Forum 1048 (4 janvier 2022) : 359–65. http://dx.doi.org/10.4028/www.scientific.net/msf.1048.359.
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In this study, an experimental investigation was done to study the behaviour of Normal Strength Concrete (NSC) and High Strength Concrete (HSC) Plain beams under torsion with the concrete mix of M40 and M100. No mineral admixtures are used to obtain the required strength of concrete. Eight NSC beams and eight HSC beams whose width was varying with 75 mm, 100 mm, and 150 mm; depth varying as 75 mm, 100 mm, 150 mm and 200 mm; and span of the beams varying 600 mm, 800 mm and 1200 mm were casted and cured to stud the effect of torsion. The principle aim of this study was to understand the torsional behaviour of the NSC and HSC beams for rotation, cracking, size effect and torsional strength. A standard torsional loading method was used for conducting the testing of beams. The results obtained were compared with different theories and code equations. It was observed that the torsional strength of the beam increases with the increase in strength of concrete. HSC beams have higher torsional strength than the NSC beams which has the same amount of reinforcement.
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Al-Thairy, Haitham. « Effect of Using River Sand on The Strength of Normal and High Strength Concrete ». International Journal of Engineering & ; Technology 7, no 4.20 (28 novembre 2018) : 222. http://dx.doi.org/10.14419/ijet.v7i4.20.25930.
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The shortage and high cost of quarries sand in some regions around the world has motivated engineers and researchers to investigate the possibility and feasibility of using other materials to be used as a fine aggregate in concrete mixtures. The main objective of this research is to experimentally investigate the effect of using river sand as a partial replacement of the ordinary quarries sand on the mechanical properties of normal and high strength concrete. Nine concrete mixtures were prepared and tested in terms of fresh and hardened properties using different replacement ratios of the required proportion of the normal sand. Four replacement ratios were used for normal strength concrete (NSC) which are: 0%, 25%, 50% and 75%, whereas, five replacement ratios were used for high strength concrete (HSC) namely: 0%, 35%, 60% and 90%. For each strength grade, the test parameters of the prepared mixtures included compressive and tensile strength. The experimental test results have revealed that it is possible to obtain a normal and high strength concrete with acceptable compressive and flexural strengths values by using river sand with replacement ratios up to 25% and 35% for NSC and HSC, respectively. When the replacement ratios were increased to more than the aforementioned ratios, the strength of the concrete decreased accordingly.
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Almuzaini, Abdullah Sulaiman, et Omar M. Alawad. « Effect of Local Coarse Aggregates on the Compressive Strength of High Strength Concrete ». Materials Science Forum 1053 (17 février 2022) : 267–74. http://dx.doi.org/10.4028/p-x25xg7.
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This study investigates the effect of different types of local coarse aggregate, available in Saudi Arabia, on the strength of high-strength concrete. The utilized coarse aggregates are basalt and two different aggregates of limestone, denoted as limestone 1 and limestone 2. The results of 7 and 28 days compressive strength with different percentages of Micro Silica (MS) (i.e. range from 0 to 10%) show that the compressive strength of high strength concrete (HSC) is influenced by the type of coarse aggregate. Limestone 2 reaches the highest compressive strength followed by the types limestone 1 and then basalt. Properties of coarse aggregate influence the compressive strength of HSC, such as impact value (AIV), and texture. Also, the impact value variation between saturated surface dry (SSD) and dry conditions of the coarse aggregate affect significantly the compressive strength of HSC.
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DRZYMAŁA, Tomasz, Wioletta JACKIEWICZ-REK, Jerzy GAŁAJ et Ritoldas ŠUKYS. « ASSESSMENT OF MECHANICAL PROPERTIES OF HIGH STRENGTH CONCRETE (HSC) AFTER EXPOSURE TO HIGH TEMPERATURE ». Journal of Civil Engineering and Management 24, no 2 (25 avril 2018) : 138–44. http://dx.doi.org/10.3846/jcem.2018.457.
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There has been a tendency to design ever slender building construction using high strength concrete in recent years. Application of HSC is also growing in tunnel construction. One of the most important challenges is to control explosive spalling of concrete and the method recommended by Eurocode 2 (EN 1992-1-2:2008/NA:2010P) is addition of polypropylene fibres to the mix. The purpose of the research described in this paper was to evaluate the changes of mechanical properties of HSC exposed to the effect of high temperature. The tests were carried out on three types of high strength concrete: air-entrained concrete, polypropylene fibre-reinforced concrete and reference concrete having constant water/cement ratio. The properties of hardened concrete including compressive strength, tensile splitting strength, flexural strength and E-modulus were studied. The latter tests were carried out on both on concrete cured at 20 °C and concrete subjected to high-temperature conditions at 300 °C, 450 °C and 600 °C. The results enabled us to evaluate the effect of high-temperature conditions on the properties of high-performance concrete and compare the effectiveness of the two methods designed to improve the high-temperature performance of the concrete: addition of polypropylene fibres and entrainment of air.
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Peng, Gai Fei, et Yan Teng. « Fire Resistance of Ultra-High-Strength Concrete : a Review ». Key Engineering Materials 477 (avril 2011) : 333–39. http://dx.doi.org/10.4028/www.scientific.net/kem.477.333.
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This paper presents a review of advances in research on fire resistance of high-strength concrete (HSC) and ultra-high-strength concrete (UHSC). Further research needs in the near future on UHSC, especially on reactive powder concrete (RPC), are also discussed. It is commonly recognized that HSC suffers strength loss in a manner basically similar to that of normal strength concrete. But the main problem of HSC is explosive spalling under high temperature, which can be solved by employing either polymer fiber or steel fiber. Since RPC200 is a type of RPC which has been successfully prepared in many counties and is to be applied to engineering practice, fire resistance of RPC200 needs a series of investigations urgently. The objectives of such investigations are to restrain explosive spalling and minimizing spalling probability, so as to ensure satisfactory fire resistance of RPC. It is expected that a research will be carried out on explosive spalling behavior, fracture properties, and micro-structure, to establish a mechanism as well as technical measures for improving fire resistance of RPC.
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Yu, Kequan, Jiangtao Yu, Zhoudao Lu et Qingyang Chen. « Fracture properties of high-strength/high-performance concrete (HSC/HPC) exposed to high temperature ». Materials and Structures 49, no 11 (25 janvier 2016) : 4517–32. http://dx.doi.org/10.1617/s11527-016-0804-x.
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Assi, Nizar, Husain Al-Gahtani et Mohammed A. Al-Osta. « Numerical Investigation of Stress Block for High Strength Concrete Columns ». Civil Engineering Journal 6, no 5 (1 mai 2020) : 974–96. http://dx.doi.org/10.28991/cej-2020-03091522.
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This paper is intended to investigate the stress block for high strength concrete (HSC) using the finite element model (FEM) and analytical approach. New stress block parameters were proposed for HSC including the stress intensity factor (α1) and the depth factor (β1) based on basic equilibrium equations. A (3D) finite element modeling was developed for the columns made of HSC using the comprehensive code ABAQUS. The proposed stress parameters were validated against the experimental data found in the literature and FEM. Thereafter, the proposed stress block for HSC was used to generate interaction diagrams of rectangular and circular columns subjected to compression and uniaxial bending. The effects of the stress block parameters of HSC on the interaction diagrams were demonstrated. The results showed that a good agreement is obtained between the failure loads using the finite element model and the analytical approach using the proposed parameters, as well as the achievement of a close agreement with experimental observation. It is concluded that the use of proposed parameters resulted in a more conservative estimation of the failure load of columns. The effect of the stress depth factor is considered to be minor compared with the effect of the intensity factor.
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Yang, Kun, Qing-xuan Shi et Qi Lin. « Seismic Performance and Confinement Reinforcement Design of High-Strength Concrete Columns Confined with High-Strength Stirrups ». Advances in Structural Engineering 24, no 10 (5 février 2021) : 2061–75. http://dx.doi.org/10.1177/1369433221992491.
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This paper aims at analyzing the failure process, failure modes, characteristics of hysteresis loop and the ductility of 10 high-strength concrete (HSC) columns confined by high-strength complex stirrups under cyclic lateral force and a higher constant axial loading. It is indicated that the hysteresis loop of this type of columns still show plump spindle-shaped at higher axial compression ratio, which shows better ductility, energy dissipation and anti-collapse performance. Therefore, it is an effective measure of setting high-strength stirrups to ensure the good ductility of HSC columns under high axial compression ratio and to increase the limit value of axial compression ratio. The stress of transverse reinforcement is evaluated, which shows that high-strength stirrups have yielded when most of the specimens are destroyed, and the strength of stirrups can be fully developed to provide a better effect of restraint. Based on a large number of experimental data, the relationships between the limit drift, the ductility coefficient of HSC columns and axial compression ratio, stirrup characteristic values, covering layer as well as longitudinal reinforcement ratio are established; the calculation formula of minimum stirrups characteristic value of HSC columns at different seismic levels considering of axial compression ratio is presented.
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Su, Xiao Ping. « Comparison Analysis on the Mechanical Properties of HSC and NSC after the Action of High Temperatures ». Advanced Materials Research 1014 (juillet 2014) : 49–52. http://dx.doi.org/10.4028/www.scientific.net/amr.1014.49.
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With the wide application of high strength concrete in the building construction,the risk making concrete subject to high temperatures during a fire is increasing. Comparison tests on the mechanical properties of high strength concrete (HSC) and normal strength concrete (NSC) after the action of high temperature were made in this article, which were compared from the following aspects: the peak stress, the peak strain, elasticity modulus, and stress-strain curve after high temperature. Results show that the laws of the mechanical properties of HSC and NSC changing with the temperature are the same. With the increase of heating temperature, the peak stress and elasticity modulus decreases, while the peak strain grows rapidly. HSC shows greater brittleness and worse fire-resistant performance than NSC, and destroys suddenly. The research and evaluation on the fire-resistant performance of HSC should be strengthened during the structural design and construction on the HSC buildings.
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Arslan, Guray, et Ercan Cihanli. « CURVATURE DUCTILITY PREDICTION OF REINFORCED HIGH‐STRENGTH CONCRETE BEAM SECTIONS ». JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 16, no 4 (31 décembre 2010) : 462–70. http://dx.doi.org/10.3846/jcem.2010.52.
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The ductility of reinforced concrete beams is very important, since it is essential to avoid a brittle failure of the structure by ensuring adequate curvature at the ultimate limit state. One of the procedures used to quantify ductility is based on curvatures, namely, curvature ductility. It is necessary to know the curvature ductility of singly reinforced high‐strength concrete (HSC) sections for determining a maximum permissible tensile reinforcement ratio or a maximum depth of the concrete compression area in design codes. The requirements of several codes and methods of prediction of the curvature ductility are based on the experimental results of normal strength concrete (NSC). The rules derived for NSC sections may not be appropriate for HSC sections, and verifications and modifications may be required for the evaluation of curvature ductility of HSC sections. In this study, the major factors affecting the curvature ductility of a singly reinforced HSC beam section are investigated. Based on numerical analyses, a parametric study has been carried out to evaluate the effects of various structural parameters on the curvature ductility of reinforced HSC beam sections. Santrauka Gelžbetoniniu siju plastiškumas yra labai svarbi savybe, apsauganti konstrukcija nuo staigios irties. Tam užtikrinti reikalinga atitinkama kreive, esant tinkamumo ribiniam būviui. Plastiškumas ivertinamas naudojant kreivines diagramas – plastiškumo kreives. Norint nustatyti didžiausia tempiamos armatūros kieki arba didžiausia gniuždomosios zonos aukšti, remiantis normomis reikia žinoti armuoto stipriojo betono (HSC) plastiškumo kreive. Kai kurios normos ir metodai plas‐tiškumo kreive nustato pagal paprastojo betono (NSC) eksperimentinius duomenis. Taisykles, skirtos paprastojo betono skerspjūvio plastiškumo kreivei nustatyti, gali netikti stipriajam betonui, todel reikia atlikti papildomus tyrimus ir metodu pakeitimus. Šiame darbe tiriami pagrindiniai veiksniai, darantys itaka stipriojo betono plastiškumo kreivei. Atliekant skai‐tini modeliavima, buvo ivertinti ivairūs skerspjūvio konstrukciniai parametrai, darantys poveiki stipriojo betono plas‐tiškumo kreivei.
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Ali, Mohsin, Aneel Kumar, Samar Hussain Rizvi, Sabir Ali et Israr Ahmed. « Effect of Polyester Fiber on Workability Property of High Strength Concrete ». Quaid-e-Awam University Research Journal of Engineering, Science & ; Technology 18, no 02 (31 décembre 2020) : 102–8. http://dx.doi.org/10.52584/qrj.1802.15.
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The utilization of (HSC) high strength concrete in the construction industry is increasing all over the world because it reduces the cross-section of structural members and increases floor area. High strength concrete can be produced by using high cement content with low w/c ratio, mineral admixtures, and chemical admixture, and with suitable fiber. Nevertheless, in this research, HSC mix was achieved with the use of a special type BASF Master (M)/Polyheed 996 super-plasticizer based on polycarboxylic ether available in the market which reduced the w/c of concrete mixes, albeit attaining adequate workability. Compressive strength, up to 63 Mpa at 28 days, was achieved at slump value 178 mm by utilizing locally available materials like cement, sand, and coarse aggregates with a maximum 1.2% (by weight of cement) dosage of super-plasticizers. HSC has high workability, and to control the workability, different percentages of polyester fiber length 32 mm were also added to HSC. Polyester fiber controls the workability and improves the properties of HSC. There were four mixes designed with polyester fiber. The addition of polyester fiber content was 0.2%, 0.3%, 0.4%, and 0.5% (by weight of cement) in HSC, and the slump value were 153mm, 127mm, 102mm and 76mm respectively. It was observed that the usage of polyester fiber (0.2% to 0.5%) decreases workability by 14% to 57% of HSC. Therefore, it was concluded that increasing the percentage of fiber decreases the slump to the required value.
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Ramesh, Vemundla, et Chitla Raju. « Effect of different grades of concrete on rc framed multi-storied building ». E3S Web of Conferences 309 (2021) : 01194. http://dx.doi.org/10.1051/e3sconf/202130901194.
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Due to the application of advanced material technology, concrete with high compressive strength is currently produced and used in many countries. This type of concrete can be produced by micro-silica and superplasticizers as well as applying good quality control procedures. The use of high-strength concrete (HSC) in building construction is becoming popular because it has many advantages such as increased strength and stiffness, reduced size of concrete sections, improved resistance to creep and drying shrinkage, and material durability. Therefore we can use high strength concrete (HSC) in columns and normal strength concrete (NSC) for beams & floor sections. Thus this study will investigate the performance of 8 storey tall buildings in ZoneIV for medium grade soil with varying high strength concrete (HSC) normal strength concrete (NSC) subjected to far-field ground motions scaled to collapse of the structure using varying grades (M20, M25, M30, M35, M40, and M50) of concrete strength subjected to seismic ground motions scaled to collapse of the structure using a linear static method and this will be achieved through analytical modeling and analysis using ETABS2018 software.
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Britez, C., P. Castro-Borges, A. Berto et P. Helene. « Experimental evaluation of colored HSC column in fire conditions ». Revista ALCONPAT 3, no 1 (30 janvier 2013) : 39–54. http://dx.doi.org/10.21041/ra.v3i1.42.
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ABSTRACTIn recent times it has been common to associate high-strength concrete with a greater susceptibility to explosive type spalling, when subjected to high temperatures. In part, this doubt is a result of some experimental programs that are carried out on small unreinforced concrete samples (specimens), which could substantially influence the structural concrete behavior in fire conditions. This paper presents an experimental program, carried out in Brazil on a high strength colored reinforced concrete column (HSCC), eight years-old, fc,8years = 140MPa, basalt coarse aggregate, cross section of 700mm x 700mm, tested under no load and with three faces exposed to standard fire curve ISO 834 for 180min (3h). The results demonstrated, in this case, that HSCC maintained integrity under experimental fire and that the iron oxide pigments can work as an excellent natural thermometer, contributing to the evaluation of the structure post-fire simulation.Keywords: High-strength concrete; fire resistance; colored concrete; column in fire; iron oxide pigment. RESUMENHa sido común asociar el concreto de alta resistencia con una mayor susceptibilidad al desprendimiento por explosión (spalling) cuando se le somete a altas temperaturas. Esta duda se debe en parte a los resultados de algunos programas experimentales que se han llevado a cabo en pequeñas probetas de concreto simple sin refuerzo, lo que puede influir sustancialmente en el comportamiento del concreto en situación de incendio. Este artículo presenta un programa experimental en Brasil donde un pilar de concreto armado colorido de alta resistencia (HCAR), con ocho años de edad, fc,8años = 140MPa, árido grueso basáltico, sección cuadrada de 700mm x 700mm, fue ensayado sin carga y con tres lados expuestos al fuego (curva ISO 834) durante 180min (3h). Los resultados demostraron en este caso que el HCAR se mantuvo íntegro y que los pigmentos de óxido de hierro pueden trabajar como excelente termómetro natural, contribuyendo en la evaluación de la estructura después de la simulación de incendio.Palabras Clave: Concreto de alta resistencia; resistencia al fuego; concreto colorido; pilar sometido al fuego; pigmento de óxido de hierro.
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Eid, Rami, Boris Muravin et Konstantin Kovler. « Acoustic Emission Monitoring of High-Strength Concrete Columns Subjected to Compressive Axial Loading ». Materials 13, no 14 (13 juillet 2020) : 3114. http://dx.doi.org/10.3390/ma13143114.
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Acoustic Emission (AE) nondestructive tests have attracted great interest for their use in the determination of structural properties and behavior of reinforced concrete (RC) elements. One of the applications this method can contribute to is in high-strength concrete (HSC) columns. These elements have a great advantage in the lower stories of high-rise buildings. However, the premature failure of the concrete cover and the brittleness nature of the failure is of a concern for engineers. This paper presents a study on the AE monitoring of HSC columns subjected to compressive axial loading. The study consists of four large-scale reinforced HSC columns with different confinement reinforcement and height. It is shown that the AE distributions in the columns are categorized by three stages. Moreover, the levels of loads reached at the first AE macro event are similar to the lower range levels of the nominal axial compressive strengths of the tested specimens, while the majority of macro AE events are located at the concrete cover. Based on the results of this study, AE monitoring can provide indications for the damage and load levels attained by reinforced high-strength concrete columns subjected to compressive axial loading.
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Gernay, Thomas. « Fire Performance of Columns Made of Normal and High Strength Concrete : A Comparative Analysis ». Key Engineering Materials 711 (septembre 2016) : 564–71. http://dx.doi.org/10.4028/www.scientific.net/kem.711.564.
Texte intégralRésumé :
The use of high strength concrete (HSC) in multi-story buildings has become increasingly popular. Selection of HSC over normal strength concrete (NSC) allows for reducing the dimensions of the columns sections. However, this reduction has consequences on the structural performance in case of fire, as smaller cross sections lead to faster temperature increase in the section core. Besides, HSC experiences higher rates of strength loss with temperature and a higher susceptibility to spalling than NSC. The fire performance of a column can thus be affected by selecting HSC over NSC. This research performs a comparison of the fire performance of HSC and NSC columns, based on numerical simulations by finite element method. The thermal and structural analyses of the columns are conducted with the software SAFIR®. The variation of concrete strength with temperature for the different concrete classes is adopted from Eurocode. Different configurations are compared, including columns with the same load bearing capacity and columns with the same cross section. The relative loss of load bearing capacity during the fire is found to be more pronounced for HSC columns than for NSC columns. The impact on fire resistance rating is discussed. These results suggest that consideration of fire loading limits the opportunities for use of HSC, especially when the objective is to reduce the dimensions of the columns sections.
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Hatem Alani, Aktham, et Megat Azmi Megat Johari. « Influence of Silica Fume Inclusion on the Compressive Strength Development of High Strength Concrete Containing High Volume of Palm Oil Fuel Ash ». Applied Mechanics and Materials 802 (octobre 2015) : 214–19. http://dx.doi.org/10.4028/www.scientific.net/amm.802.214.
Texte intégralRésumé :
The influence of silica fume (SF) inclusion on the compressive strength development of high strength concrete (HSC) containing high volume of palm oil fuel ash (POFA) has been investigated. A HSC containing 100% ordinary Portland cement (OPC) and another HSC mix with 50% POFA as part of the binder were prepared. Due to the reduction in early strength of the HSC with the inclusion of high volume of POFA in the binary blended binder HSC, attempt was made to partially replace the OPC with SF at 5, 10, 15 and 20%, thus creating a ternary blended binder HSC. The results show that the compressive strength development of the HSC containing high volume of POFA was significantly improved with the inclusion of SF. The ternary blended binder HSC with 15% SF exhibited the highest increase in early age strength, even though it did not surpass the OPC-HSC, and it provided the highest strength at 7 and 28 days in comparison to other HSC mixes. Thus, ternary blended binder containing more than 60% supplementary cementitious material (POFA and SF) could be utilized to produce HSC.
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Liu, Shu Hua, Kun He Fang et Zeng Li. « Influence of Mineral Admixtures on Crack Resistance of High Strength Concrete ». Key Engineering Materials 302-303 (janvier 2006) : 150–54. http://dx.doi.org/10.4028/www.scientific.net/kem.302-303.150.
Texte intégralRésumé :
As high strength concrete (HSC) is widely used in construction, more and more attention has been paid to crack resistance of it. In order to improve crack resistance of HSC, we study the influence of mineral admixtures (ground slag, silica fume and fly ash) on brittleness and characteristic length as crack resistance’ indexes. Testing researches shows, without admixture, crack resistance of HSC is the lowest; when one of the three mineral admixtures added, crack resistance increases dramatically; when two of the three mineral admixtures are added in the concrete, crack resistance increases a little more and it does not change very much no matter which two are mixed; crack resistance comes out the highest when the three mineral admixtures are added in concrete. Mechanism analysis shows, Adding fine and high active ground slag, silica fume and fly ash into concrete can greatly improve microstructure of transition zone, decrease Ca(OH)2, ettringite and porosity in concrete, increase C-S-H gel and greatly reduce the original micro-cracks in the transition zone.