Evaluation of concrete bricks with crumb rubber and polypropylene fibres under impact loading

Effects of partial replacements of sand by waste fine crumb rubber on the performance of reinforced concrete under low velocity impact loading were investigated. Specimens were prepared for 5%, 10% and 20 % replacements by volume of sand. All specimens were cured in moist air for 90 days. For each case, six beams of 100 mm ×100 mm × 500mm were subjected to 5.15 kg hammer from 900mm height. The number of blows of the hammer required to induce the first visible crack of the beam were recorded. The results are presented in terms of impact energy required for the first crack. The fine crumb rubbers increased the impact energy for first crack.

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FRACTURE OF CONCRETE CONTAINING CRUMB RUBBER

Journal of Civil Engineering and Management ◽

10.3846/13923730.2013.782335 ◽

2013 ◽

Vol 19 (3) ◽

pp. 447-455 ◽

Cited By ~ 22

Author(s):

Audrius Grinys ◽

Henrikas Sivilevičius ◽

Darius Pupeikis ◽

Ernestas Ivanauskas

Keyword(s):

Fracture Energy ◽

Mouth Opening ◽

Crumb Rubber ◽

Crack Mouth Opening Displacement ◽

Concrete Fracture ◽

Opening Displacement ◽

Polypropylene Fibres ◽

Abrupt Decrease ◽

Resistance To Stress ◽

Maximum Stresses

Every year, colossal amounts of used and non-biodegradable rubber tyres are accumulated in the world. Experience shows that the most efficient way to increase the concrete fracture energy G F (N/m) is to use metal or polypropylene fibres. The optimal content of fibre increases concrete resistance to stress (especially tensile stress under bending force). Concrete fracture is not brittle; concrete continues deforming after maximum stresses and is able to resist certain stresses, there is no abrupt decrease in loading. The research has proved that crumb rubber can be used in concretes as an alternative to metal and polypropylene fibres. The investigation has found that rubber waste additives, through their specific properties can partly take up tensile stresses in concrete and make the concrete fracture more plastic; besides, such concrete requires a significantly higher fracture energy and concrete samples can withstand much higher residual strength at 500 µm crack mouth opening displacement (CMOD) and deflection.

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Effect of Fibres on Bond Behaviour Under Impact Loading

MRS Proceedings ◽

10.1557/proc-211-139 ◽

1990 ◽

Vol 211 ◽

Author(s):

Cheng Yan ◽

Sidney Mindess

Keyword(s):

Impact Loading ◽

Steel Fibre ◽

Polypropylene Fibre ◽

Reinforcing Bars ◽

Polypropylene Fibres ◽

Bond Behaviour ◽

Steel Fibres

AbstractThe bond between concrete and reinforcing bars under impact loading was studied for plain, polypropylene fibre reinforced, and steel fibre reinforced concretes. It was found that adding steel fibres significantly improved the bond behaviour under impact loading; polypropylene fibres had a much smaller effect.

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Degradation of crumb rubber modified railway ballast under impact loading considering aggregate gradation and rubber size

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0596 ◽

2021 ◽

pp. 1-13

Author(s):

Mehdi Koohmishi ◽

Alireza Azarhoosh

Keyword(s):

Impact Loading ◽

Large Scale ◽

Dynamic Effect ◽

Crumb Rubber ◽

Railway Track ◽

Impact Loads ◽

Railway Ballast ◽

Loading Test ◽

Aggregate Gradation ◽

Established Procedure

Impact loads generated from the dynamic effect of passing trains can exacerbate the degradation level of ballast aggregate of railway track. To diminish the induced impact loads, the use of crumb rubber (CR) in the ballast course is characterized as a well-established procedure related to the modification of utilized material. Nonetheless, more in-depth assessments of size and percentage of CR particles combined with ballast aggregate are still required. The present study evaluates the influence of size and content of CR particles used for degradation reduction of ballast aggregate subjected to impact loading. For this purpose, a large-scale impact loading test is carried out on prepared specimens of aggregate by considering the initial gradation, subgrade condition, as well as the size and content of CR particles. The results indicate less ballast degradation for a higher percentage of CR particles. Meanwhile, the enhancement of rubber modified ballast against deterioration is further highlighted in the case of rigid subgrade. In addition, incorporation of larger-sized CR particles (12.5–25 mm) in a ballast specimen comprising more uniform gradation of aggregate can more effectively diminish the amount of degradation. Nevertheless, using smaller-sized CR particles (4.75–9.5 mm) for a ballast sample consisting of a broader range of sizes can better improve resistance against degradation.

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Investigation into Recycled Rubber Aggregates and Steel Wire Fiber for Use in Concrete Subjected to Impact Loading

Infrastructures ◽

10.3390/infrastructures5100082 ◽

2020 ◽

Vol 5 (10) ◽

pp. 82

Author(s):

Steven M. Tate ◽

Hiwa F. Hamid ◽

Stephan A. Durham ◽

Mi G. Chorzepa

Keyword(s):

Impact Loading ◽

Steel Fiber ◽

Steel Wire ◽

Crumb Rubber ◽

Impact Testing ◽

Steel Fibers ◽

Small Scale ◽

Recycled Steel ◽

Rubber Aggregates ◽

Powdered Rubber

This study investigated the potential use of tire derived rubber aggregates, particularly powdered rubber, and recycled steel-wire fibers in concrete subjected to impact loading. The fibers are approximately 0.4 mm in average diameter and 25 mm in length on average. There are two main portions to this study. The first phase of this study involved small-scale batching to investigate the fresh and hardened properties of concrete mixtures with powdered rubber up to 50% replacement of sand volume and recycled steel fibers up to 0.25% by mixture volume. Additional mixtures containing powdered rubber, crumb rubber, and tire chips were evaluated for their mechanical performance. Based on fresh concrete properties, compressive strength, modulus of rigidity, and impact resilience, mixtures were selected for a second investigative phase. In this phase, static and impact testing were performed on two sets of scaled beams. One beam set was produced with concrete containing 40% powdered rubber as a sand replacement and another beam set with a combination mixture incorporating rubber products of varying sizes (10% powdered rubber, 10% crumb rubber, and 10% tire chip) and 0.25% recycled steel fiber. Flexural performance improved initially with the inclusion of powdered rubber but decreased with increasing concentrations. Mixtures including recycled steel fibers at 0.25% outperformed industrial steel fiber mixtures in both flexural strength and impact resistance. For both the static and impact beams with the recycled powdered rubber and steel fibers in the combination demonstrated improved load distribution and load-carrying capacity, acting as a sufficient replacement for industrial steel fiber reinforcement.

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Fracture Behaviour of Fibre Reinforced Rubcrete

Materials Science Forum ◽

10.4028/www.scientific.net/msf.969.80 ◽

2019 ◽

Vol 969 ◽

pp. 80-85 ◽

Cited By ~ 2

Author(s):

Anand Raj ◽

Arshad P.J. Usman ◽

Praveen Nagarajan ◽

A.P. Shashikala

Keyword(s):

Fracture Energy ◽

Steel Fibre ◽

Fracture Behaviour ◽

Crumb Rubber ◽

Polypropylene Fibre ◽

Rubber Content ◽

Polypropylene Fibres ◽

Steel Fibres ◽

Point Bend

Fracture energy (Gf) studies provide us with means to assess the variation in ductility of concrete. This paper presents the results of fracture energy studies conducted on 18 mixes of M60 Grade concrete consisting of rubcrete (0%, 5%, 10%, 15% of crumb rubber), steel fibre reinforced rubcrete (0.25%, 0.5%, 0.75%, 1% steel fibres and 0% and 15% crumb rubber) and polypropylene fibre reinforced rubcrete (0.1%, 0.2%, 0.3% polypropylene fibres and 0% and 15% crumb rubber) using three-point bend beam tests on 60 × 100 × 500 mm specimens as per TC 50 FMC (1985). Results indicated an enhancement of fracture energy with an increase in rubber content.

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Bond between epoxy-coated reinforcing bars and concrete under impact loading

Canadian Journal of Civil Engineering ◽

10.1139/l94-009 ◽

1994 ◽

Vol 21 (1) ◽

pp. 89-100 ◽

Cited By ~ 6

Author(s):

Cheng Yan ◽

Sidney Mindess

Keyword(s):

Reinforced Concrete ◽

Strain Rate ◽

Fracture Energy ◽

Impact Loading ◽

Steel Fibre ◽

Bond Stress ◽

Fibre Reinforced Concrete ◽

Reinforcing Bars ◽

Polypropylene Fibres ◽

Steel Fibres

The bond between epoxy-coated reinforcing bars and concrete under static, high strain rate, and impact loading was studied for plain concrete, polypropylene fibre reinforced concrete, and steel fibre reinforced concrete. The bond stress, slip, crack development, the bond stress–slip relationship, and the fracture energy during the bond-slip process were investigated experimentally. The results were compared with those for uncoated reinforcing bars. It was found that for epoxy-coated rebars, the bond resistance decreased, in terms of the maximum local bond stress and the average bond stress; wider cracks developed during the bond process; and the fracture energy during bond failure decreased. It was also found that the influence of epoxy coating on the bond behaviour for push-in loading was much more significant than for pull-out loading. However, steel fibre additions at a sufficient content, and higher concrete strength, can mitigate the above effects to a considerable degree. Polypropylene fibres were much less effective in this regard than steel fibres. Key words: epoxy-coated rebars, bond, fibre concrete, strain rate, impact steel fibres, polypropylene fibres, concrete, high strength concrete.

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