Using steel fibred high strength concrete for repairing normal strength concrete beams and slabs

Author(s):  
I Iskhakov ◽  
Y Ribakov ◽  
K Holschemacher ◽  
T Mueller
2019 ◽  
Vol 1 (2) ◽  
pp. 218-224
Author(s):  
Atur P.N. Siregar

This paper discusses and reports based on the experimental investigation of the flexural ductility of singly reinforced normal strength and high strength concrete beams. Compressive concrete strength of 40 and 95 MPa were employed to create singly reinforced normal strength and high strength concrete beams, respectively. Fourteen samples made of normal and high strength concrete were engaged to observe the flexural ductility behaviour of beams on the basis of four point bend testing. Analysis on the basis of the flexural cracking, ultimate failure and curvature ductility were carried out to derive the comparison of singly reinforced normal strength and high strength beams. The beams using high strength concrete revealed a higher ductility ratio than that of normal strength concrete, i.e. 4.50 for high strength concrete and 2.60 for normal strength concrete.


2022 ◽  
Vol 1048 ◽  
pp. 359-365
Author(s):  
Ihtesham Hussain Mohammed ◽  
Ahmed Majid Salim Al Aamri ◽  
Shakila Javed ◽  
Yahya Ubaid Al Shamsi

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.


2018 ◽  
Vol 21 (11) ◽  
pp. 1723-1732 ◽  
Author(s):  
Venkatesh KR Kodur

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.


2000 ◽  
Vol 3 (3) ◽  
pp. 245-253 ◽  
Author(s):  
P. Mendis ◽  
C. French

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).


2012 ◽  
Vol 446-449 ◽  
pp. 718-727
Author(s):  
Hamid Reza Azizipesteh Baglo ◽  
Mohammed Raoof

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.


2016 ◽  
Author(s):  
Iakov Iskhakov ◽  
Yuri Ribakov

<p>Steel fibered high strength concrete (SFHSC) is effective for repairing structures from normal strength concrete (NSC). Design of NSC structures that should be repaired is based on general concepts for design of two-layer beams, developed by the authors. Such beams are effective when their section carries large bending moments. Steel fibers increase the ultimate deformations of high strength concrete. The required ductility level of the repaired element is achieved by selecting appropriate fibers' content. This is important for design of structures to dynamic loadings. The paper is focused on interpreting the experimental data in order to find the optimal fibre content and correspondingly the highest Poisson coefficient and ductility of the repaired elements’ sections. The experimental results, obtained in the frame of this study, form a basis for provisions, related to repairing of NSC beams and slabs, using SFHSC.</p>


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