scholarly journals Modified Falling Mass Impact Test Performance on Functionally Graded Two Stage Aggregate Fibrous Concrete

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5833
Author(s):  
Nandhu Prasad ◽  
Gunasekaran Murali ◽  
Nikolai Vatin
Keyword(s):  
Test Performance ◽  
Impact Test ◽  
Impact Resistance ◽  
American Concrete Institute ◽  
Functionally Graded ◽  
Test Results ◽  
Two Stage ◽  
Polypropylene Fibres ◽  
Fibre Composites ◽  
Fibrous Concrete

This research examined the performance of functionally graded two-stage fibrous concrete (FTSFC) against modified repeated falling-mass impacts. This study led to the concept of creating improved multiphysics model of fibre composites with better impact resistance for potential protective constructions. FTSFC was developed based on the bio-inspiring strength of turtle shells. The excellent impact resistance of FTSFC was accomplished by including a larger quantity of steel and polypropylene fibres in the outer layers. At the same time, one- and two-layered concrete were cast and compared to evaluate the efficiency of three-layered FTSFC. To minimize the dispersed test results, a modified form of the 544 drop-mass impact test was recommended by the American Concrete Institute (ACI). The modification was a knife-edge notched specimen instead of a solid cylindrical specimen without a notch. This modification predefined a crack path and reduced the dispersion of results. Cracking and failure impact numbers, ductility index, and failure mode were the testing criteria. The suggested modification to the ACI impact test decreased the coefficient of variance, showing that the dispersion of test results was reduced significantly. This study led to the concept of creating improved, fibre composites with better impact resistance for potential protective constructions.

scholarly journals Impact Resistance of Functionally Layered Two-Stage Fibrous Concrete

Fibers ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 88
Author(s):  
Gunasekaran Murali ◽  
Nandhu Prasad ◽  
Sergey Klyuev ◽  
Roman Fediuk ◽  
Sallal R. Abid ◽  
...  
Keyword(s):  
Impact Test ◽  
Impact Resistance ◽  
Injection Technique ◽  
Two Stage ◽  
Polypropylene Fibres ◽  
Drop Mass ◽  
Fibrous Concrete ◽  
Definition Of ◽  
Protective Structures ◽  
The Impact

The impact resistance of functionally layered two-stage fibrous concrete (FLTSFC) prepared using the cement grout injection technique was examined in this study. The impact resistance of turtle shells served as the inspiration for the development of FLTSFC. Steel and polypropylene fibres are used in more significant quantities than usual in the outer layers of FLTSFC, resulting in significantly improved impact resistance. An experiment was carried out simultaneously to assess the efficacy of one-layered and two-layered concrete to assess the effectiveness of three-layered FLTSFC. When performing the drop-mass test ACI 544, a modified version of the impact test was suggested to reduce the scattered results. Instead of a solid cylindrical specimen with no notch, a line-notched specimen was used instead. This improvement allows for the pre-definition of a fracture route and the reduction of the scattering of results. The testing criteria used in the experiments were impact numbers associated to first crack and failure, mode of failure, and ductility index. The coefficient of variation of the ACI impact test was lowered due to the proposed change, indicating that the scattering of results was substantially reduced. This research contributes to the idea of developing enhanced, more impact-resistant fibre composites for use in possible protective structures in the future.

scholarly journals Response of Novel Functionally-Graded Prepacked Aggregate Fibrous Concrete against Low Velocity Repeated Projectile Impacts

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 280
Author(s):  
Nandhu Prasad ◽  
Gunasekaran Murali ◽  
Roman Fediuk ◽  
Nikolai Vatin ◽  
Maria Karelina
Keyword(s):  
Impact Resistance ◽  
Single Layer ◽  
Functionally Graded ◽  
Low Velocity ◽  
Polypropylene Fibres ◽  
Projectile Impact ◽  
Reference Information ◽  
Fibrous Concrete ◽  
New Type ◽  
Research Gap

Preplaced Aggregate Fibrous Concrete (PAFC) is a newly minted composite that has recently become more popular. The production of PAFC involves two essential processes; first, the fibres and coarse aggregate were filled into the empty framework to form the first layer of a natural skeleton, followed by grout injecting. A cement grout fills the voids in the first layer skeleton with slight compaction. This process is repeated to complete the remaining layers; hence, a type of Functionally-graded Preplaced Aggregate Fibrous Concrete (FPAFC) is obtained. The most recent studies revealed that the literature regarding the high-velocity projectile impact on fibrous concrete is well documented; however, the low-velocity repeated projectile impact on PAFC is still unexplored and needs particular emphasis. This research aims to investigate the FPAFC made with a new type of steel and polypropylene fibres against low-velocity projectile impact to fill this research gap. In the current study, twelve mixes were prepared with mono and hybrid combinations of fibres for pioneering the possible utilization of fibres in FPAFC. The maximum fibre dosage in this study is limited to 2.4%. The projectile impact resistance of FPAFC was assessed in line with penetration depth, front and rear damage surface area, weight loss, damage ratio and failure pattern. Additionally, a simplified analytical model was introduced to compute the ejected composite mass from the tested specimens. The results revealed that the addition of steel fibre in a single layer FPAFC exhibited an increasing compressive strength trend compared to the two/three-layered FPAFC. Furthermore, increasing the dosage of fibre at the bottom and top layers of FPAFC with a hybrid combination alleviates the spalling with an increasing number of impacts. The results from this research offer the reference information for more detailed research and studies of FPAFC under low-velocity projectile impact.

scholarly journals DYNAMIC IMPACT WEAR AND IMPACT RESISTANCE OF W-B-C COATINGS

2020 ◽  
Vol 27 ◽  
pp. 37-41
Author(s):  
Josef Daniel ◽  
Jan Grossman ◽  
Vilma Buršíková ◽  
Lukáš Zábranský ◽  
Pavel Souček ◽  
...  
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Protective Coatings ◽  
Impact Resistance ◽  
Impact Testing ◽  
The Novel ◽  
Test Results ◽  
Dynamic Impact ◽  
Impact Deformation ◽  
The Impact

Coated components used in industry are often exposed to repetitive dynamic impact load. The dynamic impact test is a suitable method for the study of thin protective coatings under such conditions. Aim of this paper is to describe the method of dynamic impact testing and the novel concepts of evaluation of the impact test results, such as the impact resistance and the impact deformation rate. All of the presented results were obtained by testing two W-B-C coatings with different C/W ratio. Different impact test results are discussed with respect to the coatings microstructure, the chemical and phase composition, and the mechanical properties. It is shown that coating adhesion to the HSS substrate played a crucial role in the coatings’ impact lifetime.

scholarly journals Using the Plate-Creep test to determine the impact strength properties of concrete

2021 ◽  
Author(s):  
Murat Gökçe ◽  
Keyword(s):  
Impact Strength ◽  
Creep Test ◽  
Impact Test ◽  
Impact Resistance ◽  
Strength Properties ◽  
Test Results ◽  
Test Device ◽  
Concrete Mixtures ◽  
Repetitive Impact ◽  
The Impact

The paper aims to design a concrete against repetitive impact and abrasion resistance. Macro/micro steel fibers and two types of crushed stone based on limestone and corundum as aggregate were used in concrete mixtures. Impact test device has been modified, designed and used for impact strength testing of concrete. The usability of the plate creep test in determining the impact strength of concrete was also investigated. According to the test results, a high correlation was found between the abrasion, impact resistance tests and the creep test.

scholarly journals Resistance of External Thermal Insulation Composite Systems with Rendering (ETICS) to Hail

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2452
Author(s):  
Barbara Francke ◽  
Renata Zamorowska
Keyword(s):  
Thermal Insulation ◽  
Impact Test ◽  
Impact Resistance ◽  
Surface Damage ◽  
New Method ◽  
Test Results ◽  
Basic Premise ◽  
Composite Systems ◽  
Damage And Fracture ◽  
New Research

This paper analyzes the resistance to hail of external thermal insulation composite systems (ETICS), i.e., external thermal insulation of foamed polystyrene with the same finishing coat and various reinforcing mesh and base coats used to make the reinforced layer. The manuscript presents our own new method for assessing ETICS resistance to hail and test results obtained according to this method. The basic premise of the presented new research methodology is evaluation of the thermal insulation system surface damage and fracture toughness, in the function of hit velocity with a polyamide ball with a standardized diameter and weight. The results of hail resistance tests were compared with the values of hard body impact resistance obtained in the tests done according to ETAG 004. Results obtained by the new method help to evaluate precisely the resistance of thermal insulation sets to damage as a result of impact of heavy objects of permanent shape, with greater accuracy than the hard body impact test. They also confirmed that thermal insulation sets with dispersion adhesive in the reinforcement demonstrate greater resistance to damage as a result of hail impact than the sets with cement-based adhesives and that weight of the reinforcing mesh used in the system is not significant to affect the hail resistance.

Structure of Alumina Layer on the Damage Resistance of Multilayered CVD Coating under Repeated Impact Loading

2008 ◽  
Vol 373-374 ◽  
pp. 113-116
Author(s):  
Xiao Dong Zhu ◽  
Hai Lin Dou ◽  
Zhi Gang Ban ◽  
Yi Xiong Liu ◽  
Jia Wen He
Keyword(s):  
Metal Cutting ◽  
Impact Test ◽  
Impact Resistance ◽  
Cutting Tools ◽  
Coarse Grained ◽  
Test Results ◽  
Repeated Impact ◽  
Alumina Layer ◽  
Al2o3 Layer ◽  
Α Al2o3

Repeated impact test is an appropriate way to evaluate coating properties of metal cutting tools since the cyclic impact loading applied in the test simulates the interrupted cutting process. For hard CVD coatings with multi-layered structure, the alumina is usually of the lowest toughness and adhesion, and relatively easy to fail in the metal cutting. In the present paper, multilayered coatings consisting medium temperature TiCN, Al2O3 and TiN were deposited by chemical vapor deposition (CVD) on the tungsten carbide/cobalt substrate and evaluated using scratch adhesion test and repeated impacted test. The phase structure of alumina layers are α or )κ as usually applied in cutting tools, and the grain size for the α phase one is varied from one micron to four microns. The scratch and indentation test results show that the alumina layer of κ phase is easy to remove under the quasi-static loading, implying brittleness and low adhesion. The repeated impact test results reveal lower impact resistance for the κ phase alumina, and only adhesive failure can be found, which differs to that of the α phase one. The coarse grained α-Al2O3 layer shows similar adhesion compared to the fine grained α- Al2O3 in scratch test. The failure mode of the coating with coarse grained α-Al2O3 layer in the repeated impact test is primarily impact wear. No cohesive failure can be found at all load levels, and this leads to higher impact life than that of the fine grain one. It was shown that the relatively low adhesion of bottom TiCN layer may not affect the impact resistance.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

scholarly journals Sustainable Use of Waste Polypropylene Fibres to Enhance the Abrasion and Skid Resistance of Two-Stage Concrete

2021 ◽  
Vol 13 (9) ◽  
pp. 5200
Author(s):  
Rayed Alyousef
Keyword(s):  
Abrasion Resistance ◽  
Research Work ◽  
Sustainable Use ◽  
Plain Concrete ◽  
Skid Resistance ◽  
Two Stage ◽  
Polypropylene Fibres ◽  
Conventional Concrete ◽  
Carpet Industry ◽  
Waste Polypropylene

Two-stage concrete (TSC), also known as prepacked aggregate concrete (PAC), differs from traditional concrete in terms of site application and manufacturing process. Although this type of concrete is not a replacement for conventional concrete applications, it is an ideal option for unusual and difficult placing conditions, especially for repairing existing concrete structures. In other words, this type of concrete is a newly developed concrete and made by placing and packing coarse aggregates and fibres in a designed formwork, then injecting a cement grout mixture into the free spaces between the aggregate particles using gravity or a pump device. For the mentioned system and others, concrete components used as floors or pavements must have an adequate degree of roughness during service life when exposed to skid and abrasion. Thus, this research work introduced a new concrete method (prepacked aggregates fibre-reinforced concrete—PAFRC) with high abrasion and skid resistance reinforced with waste polypropylene (PP) fibres from the carpet industry. The effects of PP fibres at 0–1% dosages on the mechanical properties, abrasion resistance, and skid resistance of PAFRC mixes were studied. The results revealed that the addition of PP fibres reduces the compressive strength of concrete mixtures. Nonetheless, the presence of PP fibres results in PAFRC mixes having higher tensile strength, abrasion resistance, and skid resistance than plain concrete. It was detected that in both grouting methods (gravity and pump), with the addition of PP fibre up to a specific dosage, the resistance against abrasion and skid was increased by about 26% compared to plain PAC mix. Additionally, the outcomes indicated that PAFRC is a promising material for applications such as pavements with high abrasion and skid resistance.

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