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 Behaviour of ultra-high performance fibre reinforced concrete beam-column joint under cyclic loading

2017 ◽  
Author(s):  
Charles K.S. Moy ◽  
Jun Xia ◽  
Chee Chin ◽  
Jianzhong Liu
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
High Performance ◽  
Fibre Reinforced Concrete ◽  
Normal Strength Concrete ◽  
Joint Region ◽  
Strength Concrete ◽  
Column Joint ◽  
Normal Strength ◽  
High Performance Fibre

Ultra-high performance fibre reinforced concrete (UHPFRC) has very high compressive strength up to 200 MPa and exhibits strain hardening effects under flexural loading. The bond strength between UHPFRC and steel reinforcement is much better than the normal strength concrete. Therefore, there is a potential to use UHPFRC material at the beam-column joint region to reduce the congestion of reinforcement as well as to improve the seismic resistance of the structure. In this pilot study, the beam column joints made of normal strength concrete and UHPFRC were tested under lateral cyclic loading up to failure using a 500 tonne capacity computer control servo hydraulic machine. The specimen with normal strength concrete failed at the joint region while the specimen with UHPFRC material failed due to yielding of the rebars in the beam sections near the column face and no obvious cracks were observed at the joint area. The specimens with UHPFRC as joint material exhibited higher initial lateral stiffness and achieved slightly higher ultimate load capacity than the specimen with normal strength concrete.

scholarly journals Shear Bond between Ultra-High Performance Fibre Reinforced Concrete Overlays and Normal Strength Concrete Substrates

2021 ◽  
Vol 13 (15) ◽  
pp. 8229
Author(s):  
Sara Javidmehr ◽  
Martin Empelmann
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Treatment Method ◽  
Fibre Reinforced Concrete ◽  
Normal Strength Concrete ◽  
Treatment Methods ◽  
Strength Concrete ◽  
Structural Resistance ◽  
Normal Strength ◽  
High Performance Fibre

Strengthening or retrofitting of existing structures is a more sustainable and resource-efficient solution than replacing them with new constructions. To enhance the performance and effectiveness of strengthening works the use of high-performance materials is a promising method. Using ultra-high performance fibre reinforced concrete (UHPFRC) as supplementary concrete is one of such solutions leading to high structural resistance and better durability. For such UHPFRC overlays the shear bond resistance of the interface between the existing substrate, usually normal strength concrete (NSC), and the UHPFRC is a significant design aspect. This paper presents the results of push-off tests conducted on NSC-UHPFRC specimens, which were produced with different substrate treatment methods. Using different surface measurement techniques including the sand patch method and digital microscopy, the effects of substrate roughness and treatment method on shear bond behaviour and failure mechanisms are investigated, and the results are analysed with design approaches and further calculation models in the technical literature. Based on the results, the significance of considering roughness parameters and failure mode for the design of high-performance overlays is highlighted. Furthermore, the effectiveness of different substrate treatment methods is discussed and an effective treatment method is suggested.

Innovative strategies for enhancing fire performance of high-strength concrete structures

2018 ◽  
Vol 21 (11) ◽  
pp. 1723-1732 ◽  
Author(s):  
Venkatesh KR Kodur
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Published Data ◽  
Structural Members ◽  
Fire Performance ◽  
Normal Strength Concrete ◽  
Innovative Strategies ◽  
Strength Concrete ◽  
Normal Strength ◽  
Fire Conditions

High-strength concrete is being increasingly used in a number of building applications, where structural fire safety is one of the primary design considerations. Many research studies clearly indicate that the fire performance of high-strength concrete is different from that of normal-strength concrete and that high-strength concrete may not exhibit same level of performance as normal-strength concrete under fire conditions. This article outlines key characteristics that influence the performance of high-strength concrete structural members under fire conditions. Data generated in previous experimental and numerical studies are utilized to illustrate various factors that influence fire performance of high-strength concrete structural members. Based on the published data, observations and trends on the behavior of high-strength concrete members, innovative strategies for mitigating spalling and enhancing fire resistance of high-strength concrete structural members are proposed.

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.

Bond Strength of Reinforcement in High-Strength Concrete

2000 ◽  
Vol 3 (3) ◽  
pp. 245-253 ◽  
Author(s):  
P. Mendis ◽  
C. French
Keyword(s):  
Bond Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Development Length ◽  
Normal Strength Concrete ◽  
Empirical Relationships ◽  
Strength Concrete ◽  
The World ◽  
Current Design ◽  
Normal Strength

The use of high-strength concrete is becoming popular around the world. The american code, ACI 318–95 is used in many countries to calculate the development length of deformed bars in tension. However, current design provisions of ACI 318–95 are based on empirical relationships developed from tests on normal strength concrete. The results of a series of tests on high-strength concrete, reported in the literature, from six research studies are used to review the existing recommendations in ACI 318–95 for design of splices and anchorage of reinforcement. It is shown that ACI 318–95 equations may be unconservative for some cases beyond 62 MPa (9 ksi).

scholarly journals Strengthening of RC plates with mineral-bonded composite layers for enhanced impact safety

2020 ◽  
Vol 323 ◽  
pp. 01015
Author(s):  
Marcus Hering ◽  
Manfred Curbach
Keyword(s):  
Reinforced Concrete ◽  
Test Facility ◽  
Experimental Program ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Reinforcement Steel ◽  
Composite Layers ◽  
Bonded Composite ◽  
Normal Strength ◽  
Impact Experiments

The presented paper deals with a series of impact experiments conducted in the drop tower facility of the Otto Mohr Laboratory (OML) at the Technische Universität Dresden. The presented research results were generated in three projects. A number of reinforced concrete (RC) plates which were subsequently strengthened on the not-impacted side were produced and tested. As basic materials for the RC plates, a normal strength concrete (C35/45) and conventional BSt500 reinforcement steel were used. Different material combinations, cement-bonded composites were chosen for the subsequently applied strengthening layer. The paper presents the experimental program, the used test facility, and the results of the experiments and their interpretation.

Flexural Strength and Stiffness of High Strength Concrete Beams with Exposed Main Steel

2012 ◽  
Vol 446-449 ◽  
pp. 718-727
Author(s):  
Hamid Reza Azizipesteh Baglo ◽  
Mohammed Raoof
Keyword(s):  
High Strength Concrete ◽  
Large Scale ◽  
Structural Characteristics ◽  
High Strength ◽  
Design Parameters ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Beam Design ◽  
Wide Range ◽  
Normal Strength

In a number of previous publications, results were reported for a series of extensive and carefully conducted tests on large scale reinforced concrete (R.C.) beams with various extents of loss of concrete cover and exposure of main reinforcement along their spans, with such areas of simulated damage being located within their regions which are dominated by either shear or flexure. These tests on R.C. beams made with normal strength concrete have covered a wide range of first order beam design parameters, with their results used to verify the generality of various theoretical models. In the present paper, much attention will be devoted to various structural characteristics (such as ultimate strength, flexural stiffness, etc.) of similar damaged R.C. beams with the proviso that, instead of the previously used normal strength concrete, the beams are made with high strength concrete. No such results (for high strength R.C. beams) have previously been reported in the public domain.

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