scholarly journals Determination of ballistic resistance of cementitious composites

2021 ◽  
Vol 1205 (1) ◽  
pp. 012013
Author(s):  
J Vojtisek ◽  
E Bystrianska ◽  
O Koutny ◽  
J Kratochvil ◽  
M Drdlova
Keyword(s):  
High Performance ◽  
Ceramic Materials ◽  
Cementitious Composites ◽  
Cement Composites ◽  
Penetration Test ◽  
Depth Of Penetration ◽  
Ballistic Resistance ◽  
Differential Efficiency ◽  
The Relationship

Abstract The paper describes the possibility of using the DOP test, standardly used to evaluate the ballistic resistance of ceramics, to determine the ballistic resistance of cement composites. DOP - Depth of penetration test - is based on measurement of residual penetration of projectile in witness system after the sample perforation; this parameter is used to determine differential efficiency factor (DEF), characterizing the ballistic resistance of the particular material. To verify the method for non-ceramic materials, four variants of cementitious composites with compressive strengths in the range of 30–150 MPa have been tested. The obtained results confirm the method’s suitability for determining the ballistic resistance of cement composites in terms of ease of implementation, sensitivity, and accuracy of the obtained results for both composites of common strengths and high-performance variants. The paper also discusses some aspects of the relationship between the mechanical parameters of cement composites under static loading and their ballistic resistance.

Field Tests of Cementitious Composites Suitable for Protective Structures and Critical Infrastructure

2016 ◽  
Vol 722 ◽  
pp. 3-11 ◽  
Author(s):  
Jiří Štoller ◽  
Petr Dvořák
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Critical Infrastructure ◽  
Field Tests ◽  
Plain Concrete ◽  
Cementitious Composites ◽  
Fibre Reinforced Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Ballistic Resistance ◽  
Protective Structures

The paper deals with field tests of cementitious composites suitable for protective structures and critical infrastructure. The tests of ballistic resistance against contact and distant explosions are performed according to the NATO standards. The results of tests of plain concrete, steel fibre reinforced concrete and high performance fibre reinforced concrete are analysed.

scholarly journals Effect of Corundum and Basalt Aggregates on the Ballistic Resistance of UHP-SFRC

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1529
Author(s):  
Michal Mára ◽  
Přemysl Kheml ◽  
Kristýna Carrera ◽  
Jindřich Fornůsek ◽  
Radoslav Sovják
Keyword(s):  
High Performance ◽  
Mechanical Energy ◽  
3D Scanner ◽  
Depth Of Penetration ◽  
Steel Fibre Reinforced Concrete ◽  
Ballistic Resistance ◽  
Advanced Composite ◽  
Steel Core ◽  
Full Metal Jacket ◽  
Positive Effect

Ultra-high-performance steel-fibre-reinforced concrete (UHP-SFRC) is a technologically advanced composite with a high ability to absorb and dissipate mechanical energy. This work investigates the possibility of increasing ballistic resistance by adding different percentages of corundum and basalt aggregate into this type of concrete. The most common type of ammunition, a 7.62 mm × 39 mm calibre with a full-metal jacket and a mild-steel core (FMJ-MSC), was used to test all samples. The size of the damage and the mode of failure were determined using a 3D scanner operating on the principle of photogrammetry. The experimental campaign showed that the addition of basalt and, especially, corundum aggregate has a positive effect on ballistic resistance. In particular, the increase in compressive strength and the slight decrease in depth of penetration (DOP) was observed in the case of the usage of the corundum aggregate.

Crack path and fracture surface modifications in cement composites

2015 ◽  
Author(s):  
Sajjad Ahmad ◽  
Jean Marc Tulliani ◽  
Giuseppe Andrea Ferro ◽  
Rao Arsalan Khushnood ◽  
Luciana Restuccia ◽  
...  
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Cement Composite ◽  
Absorption Capacity ◽  
Cementitious Composites ◽  
Cement Composites ◽  
Stress Concentrations ◽  
Strength Capacity ◽  
Macro Scale ◽  
Applied Stresses

There is a tremendous increase in the use of high strength and high performance self-consolidating cementitious composites due to their superior workability and mechanical strengths. Cement composites are quasi-brittle in nature and possess extremely low tensile strength as compared to their compressive strength. Due to the low tensile strength capacity, cracks develop in cementitious composites due to the drying shrinkage, plastic settlements and/or stress concentrations (due to external restrains and/or applied stresses) etc. These cracks developed at the nanoscale may grow rapidly due to the applied stresses and join together to form micro and macro cracks. The growth of cracks from nanoscale to micro and macro scale is very rapid and may lead to sudden failure of the cement composites. The present paper reports the modifications in the crack growth pattern of the high performance cement composites to achieve enhanced ductility and toughness. The objective was accomplished by the incorporation of the micro sized inert particulates in the cement composite matrix. The results indicate that the incorporation of micro sized inert particles acted as the obstacles in the growth of the cracks thus improving the ductility and the energy absorption capacity of the self-consolidating cementitious composites.

scholarly journals Effect of Carbon Nanotube Size on Compressive Strengths of Nanotube Reinforced Cementitious Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tanvir Manzur ◽  
Nur Yazdani ◽  
Md. Abul Bashar Emon
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
High Performance ◽  
Construction Material ◽  
High Potential ◽  
Cement Matrix ◽  
Cementitious Composites ◽  
Cement Composites ◽  
Nanoscale Science ◽  
20 Nm

Application of nanoscale science to construction material has already begun. In recent times, various nanofibers have raised the interest of researchers due to their exceptional mechanical properties and high potential to be used as reinforcement within cement matrix. Carbon nanotube (CNT) is one of the most important areas of research in the field of nanotechnology. The size and exceptional mechanical properties of CNT show their high potential to be used to produce high performance next generation cementitious composites. In this study, an attempt has been made to investigate the effect of size of CNTs on compressive strengths of CNT reinforced cement composites. Seven different sizes of multiwalled nanotubes (MWNTs) were used to produce MWNT-cement composites. A trend was observed regarding the effect of nanotube size on compressive strength of composites in most cases. MWNT with outside diameter (OD) of 20 nm or less exhibited relatively better performance. Smaller MWNT can be distributed at much finer scale and consequently filling the nanopore space within the cement matrix more efficiently. This in turn resulted in stronger composites.

scholarly journals Simultaneous Determination of Catalpol, Aucubin, and Geniposidic Acid in Different Developmental Stages ofRehmannia glutinosaLeaves by High Performance Liquid Chromatography

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Yanjie Wang ◽  
Dengqun Liao ◽  
Minjian Qin ◽  
Xian’en Li
Keyword(s):  
Bioactive Compounds ◽  
High Performance ◽  
Developmental Stages ◽  
Iridoid Glycosides ◽  
Gardenia Jasminoides ◽  
Increasing Trend ◽  
Relationship Of ◽  
The Relationship ◽  
Geniposidic Acid

AlthoughR. glutinosaroots are currently the only organ source in clinics, its leaves are a potential supplement for the roots especially in extraction of some important bioactive compounds. Our early work found that the contents of catalpol and total iridoid glycosides varied among different developmental stages ofR. glutinosaleaves. Aucubin and geniposidic acid, the abundant major bioactive compounds inEucommia ulmoidesandGardenia jasminoides, respectively, were found present inR. glutinosaroots, however, and have not been analyzed in its leaves. In this paper, we aimed to determine contents of these three iridoid glycosides in different developmental stages ofR. glutinosaleaves using the optimized HPLC-UV conditions. Our results showed that aucubin and GPA inR. glutinosaleaves were much lower than catalpol and showed the increasing trend with the leaf development, which was different from catalpol. This work provided the important information for future exploitation ofR. glutinosaleaves as a potential supplement for its roots in extraction of some important bioactive compounds and studying the relationship of aucubin and catalpol metabolism.

Structure of Mesoporous Aerogels

MRS Bulletin ◽  
1994 ◽  
Vol 19 (4) ◽  
pp. 49-53 ◽  
Author(s):  
Dale W. Schaefer
Keyword(s):  
Mesoporous Materials ◽  
Pore Formation ◽  
High Performance ◽  
Classification Scheme ◽  
Structural Data ◽  
Ceramic Materials ◽  
Fine Scale ◽  
Manufacturing Methods ◽  
The Relationship ◽  
New Strategies

Several emerging technologies depend on the development of porous materials with pore dimensions in the nanometer range (1 nm = 10 Å). Based on the canonical classification scheme, such materials are defined as “mesoporous materials.” Specialty uses, such as separation applications, require porosities engineered to meet stringent pore-size requirements, particularly for separating high-boiling-temperature or-ganics. In addition, commodity products, such as high-performance thermal insulation, await credible manufacturing methods to produce fine-scale pores. Finally, information discovered during the development of mesoporous materials could be helpful in finding new strategies to generate void-free ceramic materials by reverse engineering.Although several methods exist to generate nanometer porosity, our ability to tailor porosity for specific applications is still primitive. Because we lack adequate structural data and models for pore formation, the relationship between synthetic protocol and pore structure remains enigmatic.

Determination of "true" serum creatinine by high-performance liquid chromatography combined with a continuous-flow microanalyzer.

1977 ◽  
Vol 23 (7) ◽  
pp. 1281-1283 ◽  
Author(s):  
N D Brown ◽  
H C Sing ◽  
W E Neeley ◽  
S E Koetitz
Keyword(s):  
Internal Control ◽  
Continuous Flow ◽  
High Performance ◽  
Citrate Buffer ◽  
Liquid Chromatograph ◽  
Initial Injection ◽  
Cation Exchange Column ◽  
On Line ◽  
The Relationship

Abstract We coupled a high-performance liquid chromatograph with a continuous-flow microanalyzer to produce a system for specifically determinig "true" creatinine in urine and serum specimens. A selective microbore pellicular cation-exchange column and a single eluting sodium citrate buffer are used to separate the noncreatinine but Jaffé-positive constituents from the creatinine in normal and experimental specimens. The effluent is analyzed continuously, on-line, the alkaline picrate complex being developed and measured in the microanalyzer. Physiological samples, reference standards, and internal control specimens are assayed in 6-min intervals subsequent to the initial injection. The relationship between concentration and peak are is linear for creatinine standards between 5 and 10 mg/liter. Specimen volumes ranging from 1 to 25 microliters, and containing creatinine in amounts exceeding 5 ng per injected sample, can be assayed with this system.

Evaluation of a radioenzymic kit for determination of plasma catecholamines.

1980 ◽  
Vol 26 (1) ◽  
pp. 120-122 ◽  
Author(s):  
S J Tasseron ◽  
J W Fiolet ◽  
A F Willebrands
Keyword(s):  
High Performance ◽  
Plasma Catecholamines ◽  
The Other ◽  
Laboratory Activity ◽  
Test Kit ◽  
Normal Humans ◽  
Methyl Derivatives ◽  
The Relationship ◽  
Layer Chromatography

Abstract We evaluated a commercially available reagent test-kit (Upjohn) for simultaneously determining norepinephrine, epinephrine, and dopamine in 50-microL of plasma. The three catecholamines are enzymically converted into the radioactive O-methyl derivatives and separated by thin-layer chromatography. Day-to-day precision (CV) was 11, 10, and 14% for norepinephrine, epinephrine, and dopamine, respectively. The relationship between concentration of catecholamine and radioactivity (net dpm) was linear to at least 8 ng (corresponding to 1 mumol/L in plasma). Sensitivity was approximately 2 pg for dopamine, 1 pg for each of the other two catecholamines. Under our conditions, epinephrine was not quite completely resolved from the other two fractions. Catecholamine values determined in normal humans, after 30 min supine and after normal laboratory activity, agreed well with those found by other investigators. Correlation was good between kit results and those obtained in another laboratory that used self-prepared reagents and "high-performance" liquid chromatography for the separation.

scholarly journals Considerations on Dop (Depth Of Penetration) Test for Evaluation of Ceramics Materials Used in Ballistic Protection

2017 ◽  
Vol 69 (1) ◽  
pp. 162-166 ◽  
Author(s):  
Ioan-Dan Popa ◽  
Florin Dobriţa
Keyword(s):  
Ceramic Materials ◽  
Special Focus ◽  
Penetration Test ◽  
Depth Of Penetration ◽  
Protection Level ◽  
Ballistic Protection ◽  
Tremendous Amount ◽  
Materials Used ◽  
Penetration Tests

Abstract Tremendous amount of funds and other resorces were invested in studying the response of ceramic materials under ballistic impact, the main goal being to find a way to increase the protection of soldiers and the vehicles used in the modern battlespace. Using of ceramic materials especially carbon based (carbides), nitrogen based (nitrides) and oxygen based (oxides) ceramics in order to increase the protection level of ballistic equipment could be, sometimes, a big challenge when trying to use the proper test in order to evaluate and compare their performances. The role of the tests is to provide a better understanding of their response in different situations and, as a consequence, to make them more efficient as armour components through future improvements. The paper presents shortly the main tests which are used and eventually standardised for evaluating the ballistic behaviour of the ceramics and other armour components, with a special focus to DOP (Depth of Penetration) Tests.

scholarly journals Determination of Shape Coefficient in Elastic Modulus Estimation with Penetration Test

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Tongbin Zhao ◽  
Rui Mao ◽  
Kai Fang ◽  
Biwen Zhang ◽  
Fenghai Yu
Keyword(s):  
Elastic Modulus ◽  
Soft Rock ◽  
Confining Pressure ◽  
Test Results ◽  
Penetration Test ◽  
Shape Coefficient ◽  
Penetration Behavior ◽  
Penetration Tests ◽  
The Relationship

Elastic modulus is a significant parameter in design and construction for rock engineering. Rock penetration test as a convenient method to evaluate the modulus of rocks has a great potential to be used. Based on the elastic theory, the relationship between rock penetration behavior and elastic modulus was established. In order to evaluate the elastic modulus, the shape coefficient is an important parameter to be determined. However, due to many factors, the value of this parameter is still uncertain. To provide a better insight into the shape coefficient and its factors, a series of penetration tests which used several types of rock samples with different sizes were conducted to study the determination of shape coefficient under different conditions. The test results show that sample size influences the shape coefficient, and with the increase in size, the shape coefficient decreases gradually to a stable value. In contrast, confining pressure has less effect on shape coefficient, and in the moderate and low stresses region, a fixed value can be selected for the test. Different types of rocks correspond to different shape coefficients. The shape coefficient of hard rock is higher than that of soft rock. Shape coefficient should be selected reasonably according to the penetration depth in practical application, and the reason, furthermore, why back-calculated shape coefficient deviates from the theoretical value is also discussed.

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