Functionally Layered Thin Slabs Made from UHPC and ECC Composites

2017 ◽  
Vol 259 ◽  
pp. 90-96
Author(s):  
Milan Rydval ◽  
David Čítek ◽  
Jiří Kolísko ◽  
Šárka Nenadálová ◽  
Tomáš Bittner
Keyword(s):  
Tensile Strength ◽  
Deformation Modulus ◽  
Steel Fibers ◽  
Modulus Of Rupture ◽  
High Ductility ◽  
Structural Elements ◽  
Thin Slab ◽  
Load Bearing ◽  
Lower Tensile Strength ◽  
Bearing Part

Corrosion of short steel fibers is one of the limit factors for using cement based UHPC material like an architectural concrete. The steel fibers corrosion is undesirable effect. PVA fibers and TRC reinforcement are nowadays used for facade elements. Structural elements reinforced by non-conventional reinforcement have lower tensile strength, also modulus of rupture is lower, due to low tensile strengths and deformation modulus of PVA and TRC. The tensile strength is determined by properties of mixture design. The potential of functionally layered thin slabs consist on the high ductility and tensile strength of UHPC matrix reinforced by short steel fibers. The load bearing part of functionally layered slabs is made by UHPC reinforced by steel fibers and the covering part is made by ECC reinforced by PVA fibers. Ductile and durable elements should be prepared by acceptable ratio between load bearing part and covering part of functionally layered thin slab. Functionally layered slabs should be used for architectural facade elements.

scholarly journals Effect of Steel Fibers on Heat of Hydration and Mechanical Properties of Concrete Containing Fly Ash

2019 ◽  
Vol 38 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Sajid Mehmood ◽  
Faheem Butt
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Construction Projects ◽  
Heat Of Hydration ◽  
Steel Fibers ◽  
Modulus Of Rupture ◽  
Consistent Increase ◽  
Lower Heat

This study investigated the effects of steel fibers on the fresh and hardened properties, and heat of hydration of concrete containing FA (Fly Ash). A total of 192 samples were cast comprising cubes, cylinders, and prisms, for six concrete mixes with varying contents of steel fibers by volume and a fixed content of FA i.e. 15% by weight of cement. The semi adiabatic setup was used to monitor temperature rise due to the heat of hydration in the concrete mixes for fourteen days. The use of FA increased workability, and decreased early compressive strength, tensile strength and heat of hydration of concrete. However, an increase in the compressive strength of FA concrete was observed by the addition of steel fibers up to 0.9% whereas a consistent increase in the splitting tensile strength and modulus of rupture was observed with the addition of the steel fibers from 0.4-1.8%. Further the test results showed that increasing steel fibers content decrease the evolution of heat due to hydration. It was concluded that the FA concrete with steel fibers can be used in precast industry and mass construction projects due to the improved mechanical properties and lower heat of hydration.

Development of wood structural elements for fire resistant buildings

2018 ◽  
Vol 9 (2) ◽  
pp. 126-137
Author(s):  
Hirokazu Ohashi ◽  
Shinya Igarashi ◽  
Tsutomu Nagaoka
Keyword(s):  
Fire Resistance ◽  
Urban Areas ◽  
Research Work ◽  
Structural Elements ◽  
Wood Structures ◽  
Load Bearing ◽  
Content Type ◽  
Glued Laminated Timber ◽  
Japanese Law ◽  
Bearing Part

Purpose As forestry contributes to the reduction of greenhouse gases by CO2 fixation, in recent years, use of wood in buildings has attracted all over the world more attention. However, construction of large wood structures is almost inexistent within urban areas in Japan. This is due to the Japanese law on fire protection of wood buildings in cities, which is considered very strict with severe requirements. This paper aims to present a research work relative to the development of one-hour fire-resistant wood structural elements for buildings in cities. The developed elements are composed of three layers made of laminated timber. Design/methodology/approach These wood structural elements, made of glued laminated timber with self-charring-stop, have sufficient fire resistance during and after a fire and comply with the strict Japanese standard for wood structural elements, which stipulates that such elements have to withstand the whole dead-load of concerned buildings after fire. To comply with such requirements, new elements of glued laminated timber with self-charring-stop layer were developed, and their performance was confirmed. Several fire-resistant tests conducted on columns, beams, column-beam joints, connections between beams and walls and beams with holes were carried out. Findings All tests proved that the elements have sufficient fire resistance. No damage was found out at the load-bearing part of the elements after testing. As the developed elements have two layers protecting the load-bearing part, the temperature in the load-bearing part could be retained below 260°C (carbonization temperature) and provide the elements with a sufficient fire resistance for 1 h. Practical implications These wood structural elements have already been applied in six projects, where large-size wooden buildings were constructed in urban areas in Japan. Originality/value The proposed structural elements use a novel technique. Every wooden element is composed of three layers made of glued laminated timber. The elements have a typical performance of self-charring-stop after fire without need for water of firefighters. More technologies related to these elements, including column-beam joints and beams with holes and effect of crack, were also developed to design and construct safe wooden buildings.

scholarly journals Estudio del comportamiento en zonas sísmicas del hormigón pretensado con refuerzo de fibras = Study of the behavior in seismic zones of reinforced prestressed concrete

2016 ◽  
Vol 2 (3) ◽  
pp. 20
Author(s):  
Eugenia Soledad Carbel
Keyword(s):  
Tensile Strength ◽  
Prestressed Concrete ◽  
Comparative Evaluation ◽  
High Performance ◽  
Steel Fibers ◽  
Deformation Characteristics ◽  
Structural Elements ◽  
Structural Walls ◽  
Conventional Concrete ◽  
Polyamide Fibers

ResumenEl hormigón pretensado reforzado con fibras, presenta simultáneamente las ventajas de los hormigones pretensados y de los reforzados con fibras. Se consigue un material de altas prestaciones en cuanto a su tenacidad, ductilidad y resistencia a la tracción, como así también para mejorar las características de agrietamiento y de deformación de los elementos estructurales del hormigón causados por solicitaciones sísmicas. En este trabajo se ha estudiado el comportamiento mecánico de un hormigón pretensado reforzado con fibras de acero y de poliamida , y su capacidad de resistir las grandes fuerzas de inercia causadas por las solicitaciones sísmicas. Para una evaluación comparativa se presentan ensayos de corte cíclico entre muros estructurales construidos con hormigón convencional y los reforzados con fibras, mediante modelos de histéresis. Los resultados muestran la variación de respuesta del hormigón con el tiempo, la diferencia existente con los hormigones tradicionales y la viabilidad del empleo de fibras. Comprobando que la adición de fibras en el hormigón armado convencional puede mejorar las actuaciones estructurales y funcionales, de las estructuras de hormigón relacionadas a las acciones sísmicas, a su vez las fibras de acero son más eficaces en mejorar el rendimiento de corte de PCCV que fibras de poliamida.AbstractPrestressed concrete reinforced with fibers, simultaneously presents the advantages of prestressed concrete and reinforced with fibers. It achieves a high performance material in terms of its toughness, ductility and tensile strength, as well as to improve the cracking and deformation characteristics of the structural elements of the concrete caused by seismic stresses. In this work the mechanical behavior of a prestressed concrete reinforced with steel and polyamide fibers and its ability to withstand the large forces of inertia caused by seismic stresses has been studied. For a comparative evaluation, cyclic cutting tests are presented between structural walls constructed with conventional concrete and those reinforced with fibers using hysteresis models. The results show the variation of concrete response with time, the existing difference with traditional concrete and the feasibility of using fibers. Finding that the addition of fibers in conventional reinforced concrete can improve the structural and functional performances of concrete structures related to seismic actions, in turn steel fibers are more effective in improving the PCCV cutting performance than fibers of polyamide.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

scholarly journals Effect of length of steel fibers of waste tires on splitting tensile strength of concrete

2019 ◽  
Vol 276 ◽  
pp. 01003 ◽  
Author(s):  
Aneel Kumar Hindu ◽  
Tauha Hussain Ali ◽  
Agha Faisal Habib
Keyword(s):  
Tensile Strength ◽  
Splitting Tensile Strength ◽  
Steel Fibers ◽  
Waste Tires ◽  
Concrete Cylinders ◽  
Proper Disposal

The increase in volume of vehicles ultimately increases the number of waste tires. The proper disposal or reutilization of waste tires is a challenge. This study is aimed to utilize the steel fibers of waste tires as reinforcement in concrete. Concrete cylinders were cast with addition of different percentages of steel fibers (0-2%) and length (10-20 mm). The fresh and hard properties of concrete reinforced with different percentages of steel fibers and lengths were observed. It is seen that splitting tensile strength of concrete increased with increase in the length of fiber and with the increase in the percentage of fiber. The inclusion of the fibers in concrete causes the reduction in the workability of concrete.

Mechanical properties of low-density paper

2020 ◽  
Vol 35 (1) ◽  
pp. 61-70
Author(s):  
Na Young Park ◽  
Young Chan Ko ◽  
Lili Melani ◽  
Hyoung Jin Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Structural Change ◽  
Tensile Testing ◽  
Tensile Modulus ◽  
Gauge Length ◽  
Efficiency Factor ◽  
Low Density ◽  
Tensile Stiffness ◽  
Lower Tensile Strength

AbstractFor the mechanical properties of paper, tensile testing has been widely used. Among the tensile properties, the tensile stiffness has been used to determine the softness of low-density paper. The lower tensile stiffness, the greater softness of paper. Because the elastic region may not be clearly defined in a load-elongation curve, it is suggested to use the tensile modulus which is defined as the slope between the two points in the curve. The two points which provide the best correlation with subjective softness evaluation should be selected. Low-density paper has a much lower tensile strength, but much larger elongation at the break. It undergoes a continuous structural change during mechanical testing. The degree of the structural change should depend on tensile conditions such as the sample size, the gauge length, and the rate of elongation. For low-density paper, the tensile modulus and the tensile strength should be independent of each other. The structure efficiency factor (SEF) is defined as a ratio of the tensile strength to the tensile modulus and it may be used a guideline in developing superior low-density paper products.

scholarly journals Composites from Thermoplastic Natural Rubber Reinforced Rubberwood Sawdust: Effects of Sawdust Size and Content on Thermal, Physical, and Mechanical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
High Density Polyethylene ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Shore Hardness ◽  
Thermoplastic Natural Rubber ◽  
Plastic Content

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.

scholarly journals RICE STRAW/THERMOPLASTIC COMPOSITE: EFFECT OF FILLER LOADING, POLYMER TYPE AND MOISTURE ABSORPTION ON THE PERFORMANCE

CERNE ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Hossein Mohammadi ◽  
Seyedmohammad Mirmehdi ◽  
Lisiane Nunes Hugen
Keyword(s):  
Tensile Strength ◽  
Rice Straw ◽  
Moisture Absorption ◽  
Water Immersion ◽  
Filler Loading ◽  
Thermoplastic Composite ◽  
Modulus Of Rupture ◽  
Thermoplastic Composites ◽  
Composite Effect ◽  
Wet Condition

ABSTRAT Thermoplastic composites made with 45, 60 and 75% of rice straw as filler and two types of thermoplastics, virgin polyethylene (PE) and polypropylene (PP) were evaluated. The final boards were made with and without maleic anhydride modified polypropylene (MAPP) at 2% of the total weight of each specimen. The flexural and tensile strengths were measured for dry composites and also measured after 24 h of water immersion of the composites (wet condition). By increasing the filler content, the flexural and tensile strengths and also the density of the specimens decreased. The type of matrix (PE or PP) did not affect significantly the flexural strength, but PP led to higher values of tensile strength for low fiber loadings (45% and 60%). Coupling agents increased the flexural and tensile strength. After water immersion, modulus of elasticity and modulus of rupture were decreased, while tensile strength was less influenced.

Domestic and international best practice in research and testing glass for load-bearing structures of buildings

2021 ◽  
Vol 31 (4) ◽  
pp. 5-19
Author(s):  
I. I. Vedyakov ◽  
D. V. Konin ◽  
A. A. Egorova ◽  
I. V. Rtishcheva
Keyword(s):  
Best Practice ◽  
Glass Structure ◽  
Deformation Modulus ◽  
Distinct Pattern ◽  
Design Standards ◽  
Load Bearing ◽  
Wide Range ◽  
Two Samples ◽  
Scientific Technical ◽  
Testing Standards

The present work provides an overview and analysis of scientific, technical, regulatory, and methodical Russian and foreign literature regarding using glass as a material for load-bearing structures of buildings. In the absence of design standards, an experimental study of usually one or two samples is necessary each time glass structure is used; however, this is insufficient to determine the distinct pattern of material performance. Since jointing the glass structures has been rarely studied, the number of tests is minimal, thus preventing establishing the unambiguous material operation and its calculated physical and mechanical characteristics. The article considers and evaluates the test results of glass structures obtained by various methods. The particular values of ultimate stresses and deformation modulus lie in a wide range. The technology, manufacturing process, and starting materials have a significant influence on the characteristics of glass, including multilayer glass. This article stresses the need for developing regulatory technical and methodical documents, the design and testing standards for glass structures and their jointing. It is necessary to classify load-bearing glass structures by various criteria.

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