Mechanical Properties and Durability of Bonded-Concrete Overlays and Ultrathin Whitetopping Concrete

2003 ◽  
Vol 1834 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Norbert Delatte ◽  
Anshuman Sehdev
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Normal Strength Concrete ◽  
Traffic Loading ◽  
Strength Concrete ◽  
Concrete Overlays ◽  
Normal Strength ◽  
Strength And Stiffness

Concrete overlays have been used for pavement and bridge-deck rehabilitation for many years. The mechanical properties and durability of several plain and fiber-reinforced concrete-overlay mixes were analyzed. Eight different concrete-overlay mix designs were investigated. The materials properties investigated were compressive and splitting tensile strength, modulus of elasticity, bond to concrete (with three different surface roughness characteristics), and durability. Freeze-thaw tests were performed to determine the durability of the concrete mixtures used. Strength and stiffness were investigated from 1, 3, 7, and 14 days. Laboratory tests on the strength and stiffness development of eight candidate concrete-overlay designs showed that high-strength concrete was appropriate for opening overlays to traffic in 24 h or less, but normal-strength concrete may be used if traffic loading may be delayed for 48 or 72 h. For larger projects, where paving continues over several days, normal-strength mixtures may be used when 48 to 72 h or more of curing can be achieved before traffic loading begins, with high-strength mixtures used for the last day's construction. All the high-strength concrete overlay-mixture designs tested appear to have satisfactory strength, stiffness, bond properties, and durability for use in bonded overlay construction. The normal-strength concrete is more economical than the high-strength concrete but develops its design properties more slowly.

Behavior of Densified Normal Strength Concrete under Elevated Temperature

2009 ◽  
Vol 405-406 ◽  
pp. 405-408 ◽  
Author(s):  
Bo Ming Zhao ◽  
Gai Fei Peng ◽  
Ting Yu Hao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Fire Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Polymer Fiber ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Normal Strength ◽  
Spalling Test

This paper presents an experimental investigation on fire resistance of densified normal strength concrete (DNSC), at water/binder (W/B) ratios of 0.45, 0.36, and 0.32, of which compressive strength of 28-days ranged from 42.5 MPa to 56.3 MPa. The results of the spalling test reveal that DNSC encountered explosive under high temperature. Polymer fiber can be used to improve fire resistance of DNSC. DNSC subjected to high temperature lost its mechanical properties in a similar manner to that of high-strength concrete.

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 Mechanical properties of Hybrid steel/PVA fibers reinforced high strength concrete

2018 ◽  
Vol 199 ◽  
pp. 11005 ◽  
Author(s):  
Wasim Abbass ◽  
M. Iqbal Khan
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Research Work ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Hybrid Fiber ◽  
Strength Concrete ◽  
Flexural Performance ◽  
Micro Level

The high strength concrete exhibits improved compressive strength with drawback of brittle failure due to lack of tensile strength which can be catered by the addition of fibers. The efficient use of fibers with hybridization at macro and micro level can improve mechanical properties of high strength concrete. The effect of hybridization of hooked end steel macro fibers (60 mm) and PVA micro fibers (12 mm) with different dosages was investigated in this research work. The different percentage of steel and PVA were hybridized to find out the best combination of hybridized fibers in high strength concrete. The compressive and flexural properties of high strength concrete along with complete load vs deflection behaviour of hybrid fiber reinforced concrete were investigated. The results revealed that hybridization of macro and micro fibers provided better improvement in flexural performance. It was observed from the results that the hybrid combination of fibers of 1% macro steel fiber and 0.15% micro PVA fibers proved to be the best for enhancement in flexural performance of high strength 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).

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.

Repairing of RC Structures by Steel Fibred High Strength Concrete

2016 ◽  
Author(s):  
Iakov Iskhakov ◽  
Yuri Ribakov
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Steel Fibers ◽  
Bending Moments ◽  
Normal Strength Concrete ◽  
Poisson Coefficient ◽  
Rc Structures ◽  
Strength Concrete ◽  
Dynamic Loadings ◽  
Normal Strength

<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>

Nonlinear analysis of normal- and high-strength concrete slabs

1993 ◽  
Vol 20 (4) ◽  
pp. 696-707 ◽  
Author(s):  
H. Marzouk ◽  
Z. W. Chen
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
High Strength Concrete ◽  
High Strength ◽  
Nonlinear Finite Element ◽  
Concrete Slabs ◽  
Normal Strength Concrete ◽  
Tension Stiffening ◽  
Strength Concrete ◽  
Normal Strength

Concrete slabs supported on four edges and loaded axially and transversely are used in many civil engineering applications. High-strength concrete slabs are commonly used for marine structures and offshore platforms. The catastrophic nature of the failure exhibited by reinforced concrete slabs when subjected to concentrated loads has been a major concern for engineers over many years. Therefore, there is a great need to develop accurate numerical models suitable for normal-strength or high-strength concrete in order to reflect properly its structural behaviour.Proper simulation of the post-cracking behaviour of concrete has a significant effect on the nonlinear finite element response of such slabs. Cracking and post-cracking behaviour of concrete which includes aggregate interlock, dowel action, and tension-stiffening effects is especially crucial for any nonlinear concrete analysis. The post-cracking behaviour and the fracture energy properties of high-strength concrete are different from those of normal-strength concrete. This can be realized by comparing the experimental testing results of plain normal- and high-strength concrete. The experimental results of testing plain high-strength concrete in direct tension indicated that the total area under the stress - crack width curve in tension is different from that of normal-strength concrete.A suitable softening and tension-stiffening model is recommended for high-strength concrete; other existing models suitable for normal-strength concrete are discussed. The proposed post-cracking behaviour models are implemented in a nonlinear finite element program in order to check the validity of such models by comparing the actual experimental data with the finite element results. Finally, a parametric study was conducted to provide more insight into the behaviour of high-strength concrete slabs subjected to combined uniaxial in-plane loads and lateral loads. The effects of the magnitude of in-plane load and the sequence of loading on the structural behaviour of such slabs are examined. Key words: high-strength concrete, slabs, punching shear, fracture energy, tension-softening, tension-stiffening, parametric study.

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