The Synergistic Effects of Freeze-Thaw, Salt Attack and Bending Stress on Behavior of Reinforced Concrete

2014 ◽  
Vol 633 ◽  
pp. 313-321
Author(s):  
Peng Fei Huang ◽  
Yi Wang Bao
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Dynamic Modulus ◽  
Synergistic Effects ◽  
High Strength ◽  
Bending Stress ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Damage Rate ◽  
Normal Strength

The damage experiments of reinforced concrete (RC) samples under synergistic effects of cyclic freeze-thaw, deicing-salt attack, rebar corrosion and bending stress were investigated using a comprehensive experimental method. Synergistic effects of these factors on the damage evolvement of RC were studied by measuring the change of dynamic modulus of concrete, rebar strain and concrete strain. Experimental results showed similar rule in damage evolvement but different damage rate between the normal-strength concrete (C45, the 28-day compressive strength of 52 MPa) and the high-strength concrete (C70, the 28-day compressive strength of 77 MPa). The dynamic modulus of the reinforced concrete degraded with increasing effecting factors.

Performance Deterioration of High Strength Concrete under Mixed Erosion and Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 1655-1660
Author(s):  
Jian Zhang ◽  
Bo Diao ◽  
Xiao Ning Zheng ◽  
Yan Dong Li
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mass Loss ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
High Strength Concrete ◽  
High Strength ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Dynamic Modulus Of Elasticity

The mechanical properties of high strength concrete(HSC) were experimentally investigated under mixed erosion and freeze-thaw cycling according to ASTM C666(Procedure B), the erosion solution was mixed by weight of 3% sodium chloride and 5% sodium sulfate. The mass loss, relative dynamic modulus of elasticity, compressive strength, elastic modulus and other relative data were measured. The results showed that with the increasing number of freeze-thaw cycles, the surface scaled more seriously; the mass loss, compressive strength and elastic modulus continued to decrease; the relative dynamic modulus of elasticity increased slightly in the first 225 freeze-thaw cycles, then decreased in the following 75 cycles; the corresponding strain to peak stress decreased with the increase of freeze-thaw cycles. After 200 cycles, the rate of deterioration of concrete accelerated obviously.

Tensile basic creep versus compressive basic creep at early ages: comparison between normal strength concrete and a very high strength fibre reinforced concrete

2013 ◽  
Vol 47 (10) ◽  
pp. 1773-1785 ◽  
Author(s):  
Pierre Rossi ◽  
Jean Philippe Charron ◽  
Maléna Bastien-Masse ◽  
Jean-Louis Tailhan ◽  
Fabrice Le Maou ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Strength ◽  
Basic Creep ◽  
Fibre Reinforced Concrete ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength ◽  
Very High

scholarly journals Freeze-Thaw Resistance of Normal and High Strength Concretes Produced with Fly Ash and Silica Fume

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Cenk Karakurt ◽  
Yıldırım Bayazıt
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
High Strength ◽  
Unit Surface Area ◽  
Normal Strength Concrete ◽  
Freeze Thaw ◽  
Strength Concrete ◽  
Thaw Cycle ◽  
Surface Scaling ◽  
Normal Strength

This study is based on determination of the freeze-thaw resistance of air-entrained and non-air-entrained normal strength concrete (NC) and high strength concrete (HSC) produced with fly ash and silica fume according to surface scaling. The procedure allows us to measure the amount of scaling per unit surface area due to a number of well defined freezing and thawing cycles in the presence of deicing salt. The weight loss, surface scaling, moisture uptake, and internal damage were measured after 0 and after every 4th freeze-thaw cycle. The test results showed that the freeze-thaw resistance is influenced directly by the compressive strength property of the concrete. Silica fume significantly reduced the resistance of normal strength concrete against freeze-thaw effect without plasticizing agent. The surface scaling of silica fume concrete without admixture was 22% higher than reference normal concrete.

Water Penetration Resistance of Fly Ash Concrete Incorporating with Quarry Wastes

2017 ◽  
Vol 886 ◽  
pp. 159-163 ◽  
Author(s):  
Suppachai Sinthaworn
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Strength ◽  
Cementitious Materials ◽  
Fine Aggregate ◽  
Water Penetration ◽  
Strength Concrete ◽  
Fly Ash Concrete ◽  
Suitable Amount ◽  
Normal Strength

Slump of fresh concrete, compressive strength and water penetration depth under pressure of fly ash concrete incorporate with quarry waste as fine aggregate were investigated. The cementitious materials of the concrete includes ordinary Portland cement 80% and fly ash 20% by weight of cementitious. The mix proportions of the concrete were set into two classes of compressive strength. The results show that fly ash enhances workability of both concretes (normal concrete and concrete incorporate with quarry waste). Increasing the percentage of quarry dusts as fine aggregate in concrete seem negligible effect on the compressive strength whereas adding fly ash shows a slightly improve the compressive strength in the case of cohesive concrete mixture. Besides, adding the suitable amount of fly ash could improve the permeability of concrete. Therefore, fly ash could be a good admixture to improve the water resistant of normal strength concrete and also could be a supplemental material to improve the compressive strength of normal high strength concrete.

Structural Behavior of RC Cylinders Confined with High Strength Transverse Reinforcement

2010 ◽  
Vol 163-167 ◽  
pp. 1321-1324
Author(s):  
Sang A. Cha ◽  
Cho Hwa Moon ◽  
Sang Woo Kim ◽  
Kil Hee Kim ◽  
Jung Yoon Lee
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Yield Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Structural Behavior ◽  
Transverse Reinforcement ◽  
Strength Concrete ◽  
High Rise ◽  
Compressive Strength Of Concrete

The number of high-rise reinforced concrete (RC) buildings is steadily increasing since 1980’s. The use of high strength concrete is indispensible for high-rise RC construction to ensure sufficient strength of the structure. The effect of high strength concrete can be significantly improved by the use of high strength and large size reinforcing bars. The yield strength of transverse reinforcement is limited in the current design codes to prevent possible sudden concrete failure due to over reinforcement. This paper presents the effects of the yield strength of transverse reinforcement and compressive strength of concrete on the structural behavior of reinforced concrete cylinders. Two parameters were considered in this investigation: compressive strength of concrete and the yield strength of transverse reinforcement (472MPa, 880MPa, and 1,430 MPa). Analytical and experimental results indicated that the structural behavior of RC cylinders confined with high strength transverse reinforcement is strongly influenced by compressive strength of concrete.

Experimental Study on Compressive Bearing Capacity of High Strength Concrete-Filled Steel Tube Composite Columns

2011 ◽  
Vol 368-373 ◽  
pp. 410-414 ◽  
Author(s):  
Hong Zhen Kang ◽  
Lei Yao ◽  
Xi Min Song ◽  
Ying Hua Ye
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Strength Concrete ◽  
High Strength ◽  
Steel Tube ◽  
Test Results ◽  
Concrete Filled Steel Tube ◽  
Composite Columns ◽  
Strength Concrete ◽  
Axial Compressive Strength

To study axial compressive strength of high strength concrete-filled steel tube composite columns, tests of 18 specimens were carried out. Parameters of the specimens were the confinement index of concrete-filled steel tube, the cubic strength and the stirrup characteristic value of concrete outer of steel tube. Test results show that the concrete-filled steel tube and the reinforced concrete deformed simultaneously in the axial direction before and at the peak value of axial compressive force; after failure of the reinforced concrete, the concrete-filled steel tube can still bear the axial load and deformation; the main influential factors of axial compressive capacity are confinement index, the cubic strength and the stirrup characteristic value of concrete outer of steel tube. The accuracy of the formula of axial compressive strength of composite columns provided by CECS 188:2005 is proved by the test results of this paper.

Estimation of Compressive Strength of Concrete Member Using Ultrasonic Pulse Velocity Method

2014 ◽  
Vol 605 ◽  
pp. 143-146
Author(s):  
Yong Taeg Lee ◽  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
J.H. Park
Keyword(s):  
Compressive Strength ◽  
Wave Velocity ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Concrete Member ◽  
Strength Concrete ◽  
Estimation Formula ◽  
Normal Strength

This study uses the ultrasonic pulse velocity method, one of the non-destructive testing methods that do not damage the structure, to analyze the correlation of wave velocity and compressive strength of normal strength and high strength concrete to propose an estimation formula. And a concrete member is produced to estimate the compressive strength, and provide elementary data for establishing a site-applicable standard for strength estimation formula. In order to analyze the correlation of concrete compressive strength and wave velocity, total of 144 specimens were produced per age, and six concrete members were produced for wave velocity measurement. In this study, the Ultrasonic Pulse Velocity method was used to propose a compressive strength estimation formula of normal strength and high strength concrete, which was applied to concrete members for verification, and the following conclusion was obtained. The correlation between wave velocity and compressive strength was found to be Fc=0.0952VP3.5, R2=0.82 for normal strength concrete, and Fc=0.0028VP6.1, R2=0.83 for high strength concrete. Result of comparing the estimated strength of the concrete member of the relative error rate was standard strength 18.7% on average, the high-strength 8.7%

scholarly journals Effect of size and shape of specimen on compressive strength of glass fiber reinforced concrete (GFRC)

2011 ◽  
Vol 9 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Rao Krishna ◽  
Rathish Kumar ◽  
B. Srinivas
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Glass Fiber ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Strength Concrete ◽  
Size And Shape ◽  
Glass Fiber Reinforced ◽  
Compressive Strength Of Concrete

Concrete is a versatile material with tremendous applications in civil engineering construction. Structural concrete elements are generally made with concrete having a compressive strength of 20 to 35 MPa. Lately, there is an increase in use of high strength concrete (HSC) in major construction projects such as high-rise buildings, and bridges involving members of different sizes and shapes. The compressive strength of concrete is used as the most basic and important material property in the design of reinforced concrete structures. It has become a problem to use this value as the control specimen sizes and shapes are different from country to country. In India, the characteristic compressive strength is usually measured based on 150 mm cubes [1]. But, the ACI code of practice specifies the design compressive strength based on the standard 150x300 mm cylinders [2]. The use of 100x200 mm cylinders gained more acceptance as the need to test high strength concrete increases [3]. In this context the size and shape of concrete becomes an important parameter for the compressive strength. In view of the significance of compressive strength of concrete and due to the fact that the structural elements of different sizes and shapes are used, it is proposed to investigate the effect of size and shape of the specimen on the compressive strength of concrete. In this work, specimens of plain as well as Glass Fiber Reinforced Concrete (GFRC) specimens are cast in order to carry out a comparative study.

Repaired Reinforced Concrete Beams with Normal and High Strength Concrete

2013 ◽  
Vol 6 (2) ◽  
pp. 21-37
Author(s):  
Emad Yassin Khudhair
Keyword(s):  
Reinforced Concrete ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Wire Mesh ◽  
Strength Concrete ◽  
Strength And Deformation ◽  
Normal Strength ◽  
Concrete Elements

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.

Superplasticizer for High Strength Concrete

2015 ◽  
Vol 1768 ◽  
Author(s):  
Luis E. Rendon Diaz Miron ◽  
Maria E. Lara Magaña
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
High Strength Concrete ◽  
High Strength ◽  
Mineral Admixtures ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength ◽  
Ready Mixed Concrete ◽  
Mixed Concrete

ABSTRACTIn the early 1970s, experts predicted that the practical limit of ready-mixed concrete would be unlikely to exceed a compressive strength greater than 90 MPa [1]. Over the past two decades, the development of high-strength concrete has enabled builders to easily meet and surpass this estimate. The primary difference between high-strength concrete and normal-strength concrete relates to the compressive strength that refers to the maximum resistance of a concrete sample to applied pressure. Although there is no precise point of separation between high-strength concrete and normal-strength concrete, the American Concrete Institute defines high-strength concrete as concrete with a compressive strength greater than 45 MPa. Manufacture of high-strength concrete involves making optimal use of the basic ingredients that constitute normal-strength concrete. When selecting aggregates to obtain high-strength concrete, we consider strength, optimum size distribution, surface characteristics and a good bonding with the cement paste that affect compressive strength. Selecting a high-quality Portland cement and optimizing the combination of materials by varying the proportions of cement, water, aggregates, and admixtures is also necessary. Any of these properties could limit the ultimate strength of high-strength concrete. Pozzolans, such as fly ash and silica fume along with silicic acid, are the most commonly used mineral admixtures in high-strength concrete. These materials impart additional strength to the concrete by reacting with Portland cement hydration products to create additional Calcium Silicate Hydrate (CSH) gel, the part of the paste responsible for concrete strength; finally the most important admixture is polycarboxylate ether as super plasticizer. It would be difficult to produce high-strength ready-mixed concrete without using chemical admixtures. In this paper we study the use of high performance concrete (HPC) to obtain very narrow strong pre-fabricated elements for water conducting channels.

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