Triaxial Compressive Behavior of Two Types of Concrete with Curing Conditions of Construction Site

2011 ◽  
Vol 261-263 ◽  
pp. 38-42
Author(s):  
Yi Bo Xiong ◽  
Lu Peng ◽  
Jin Xu ◽  
Liang Ma
Keyword(s):  
Failure Criterion ◽  
Raw Materials ◽  
Triaxial Compression ◽  
Experimental Program ◽  
Construction Site ◽  
Curing Conditions ◽  
Different Types ◽  
Confining Pressures ◽  
Coulomb Model ◽  
Exponential Decay Law

Based on an extensive experimental program under uniaxial and triaxial compression, this paper studies the mechanical behavior of two types of concrete with the same raw materials and the same curing conditions of the construction site. Stress-strain relations and strengths are obtained under triaxial compression with confining pressures from 10MPa to 120MPa. Material constants of different types of failure criterion are determined by the statistical method with the data from this study and public literature, including linear Mohr-Coulomb model, parabolic Willam-Warnke failure criterion and power functional Johnson-Holmquist model. The results indicate that the modulus of both types of concrete decrease as an exponential decay law with the increase of confining pressures in triaxial compression.

EFFECTS OF GEOGRID REINFORCEMENT ON THE STATIC LIQUEFACTION BEHAVIOR OF GRANULAR FILL BY TRIAXIAL TEST METHOD

2016 ◽  
Vol 78 (8-6) ◽  
Author(s):  
Mahendran N. ◽  
Hemalatha A.
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Triaxial Compression ◽  
Test Method ◽  
Experimental Program ◽  
Strain Response ◽  
Geogrid Reinforcement ◽  
Static Liquefaction ◽  
Granular Fill ◽  
Confining Pressures

Replacing theexistingweaksoilby granularfillmaterial(partialorfull)isone oftheconventionalstabilisationtechnique toimprovethebearing capacity and liquefactionbehaviorofthesoil.However, inmanycasesthedepthofreplacedgranular fillbecomesvery thick,thusleadtothe excessive cost. In the solution to this problem an experimental investigation was initiated to evaluate the effectofgeogrid reinforcementonthe staticliquefaction resistance of granularfillobtainedfrom Karaikudi, SivagangaiDistrict,Tamilnadu, India. An experimental program through triaxial compression was conduct and with various investigation on geogrid layers confining pressures. It was observedthat the extensile force of thegeogridgradually contributestothe improvementof the reinforcedspecimensshear strengthandthe extensileforceincreasedwiththeincrease inthe numberofgeogridlayers,asa result thefailuremodechangedfromshearband tobulging.Theinstalledgeogridlayersin thegranular fillimprovedthestress–strain response intermsofincrease inpeak deviatoric stressanddecrease infailure strains.Inaddition,the extensile force providesbetterinterlocking propertytothe granular   fill   be   arranged   between   the geogrid,leading tothedecreaseinthe pore waterpressure.Underaconfining pressureof150 kPatheporewaterpressure of the un-reinforced specimen was about 117 kPa,whereasthegranular fillreinforced withone,twoandthree layersofgeogrid achieved    the   pore    water   pressure   of 97.5 kPa,76.5 kPa and49.5 kPa,respectively, whichare 20.12 %,52.94 % and136.36 %, lower than thatofthe un-reinforced specimen. The findings conclude that the geogrids considerablyinfluencetheshearbehaviour of granular fill, andthe geogrid reinforcement improvesthe interlocking strengthof thegranularfill,thusimproving its shear strength

The Construction Site

2018 ◽  
Author(s):  
Mark Slobin
Keyword(s):  
Social Distance ◽  
Construction Site ◽  
Different Types ◽  
Early Influences

The chapter opens with the author’s personal and family musical formation as examples of how family, school and other early settings shape urban musical lives. Next comes a collage of short quotes from a couple dozen Detroiters to suggest how different types of early influences form musicians’ identities more generally. A short closing section discusses how the availability of many different musical sources within a metropolis helps to shape personal profiles, even as social distance keeps some styles and performances of music inaccessible.

PU composites based on different types of textile fibers

2021 ◽  
pp. 002199832110316
Author(s):  
Nuno Gama ◽  
B Godinho ◽  
Ana Barros-Timmons ◽  
Artur Ferreira
Keyword(s):  
Thermal Conductivity ◽  
Raw Materials ◽  
Natural Fibers ◽  
Tensile Modulus ◽  
High Water ◽  
Textile Fibers ◽  
Synthetic Fibers ◽  
Hydrophilic Nature ◽  
Different Types ◽  
Recycled Composites

In this study polyurethane (PU) residues were mixed with residues of textile fibers (cotton, wool and synthetic fibers up to 70 wt/wt) to produce 100% recycled composites. In addition, the effect of the type of fiber on the performance of the ensuing composites was evaluated. The presence of fibers showed similar effect on the density, reducing the density in the 5.5-9.0% range. In a similar manner, the addition of fillers decreased their thermal conductivity. The 70 wt/wt wool composite presented 38.1% lower thermal conductivity when compared to the neat matrix, a reduction that was similar for the other type of fibers. Moreover, the presence of fillers yields stiffer materials, especially in the case of the Wool based composites, which with 70 wt/wt of filler content increased the tensile modulus of the ensuing material 3.4 times. This was attributed to the aspect ratio and stiffness of this type of fiber. Finally, the high-water absorption and lower thermal stability observed, especially in the case of the natural fibers, was associated with the hydrophilic nature of fibers and porosity of composites. Overall, the results suggest that these textile-based composites are suitable for construction and automotive applications, with the advantage of being produced from 100% recycled raw-materials, without compromised performance.

scholarly journals Modified Nanoclays/Straw Fillers as Functional Additives of Natural Rubber Biocomposites

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 799
Author(s):  
Justyna Miedzianowska ◽  
Marcin Masłowski ◽  
Przemysław Rybiński ◽  
Krzysztof Strzelec
Keyword(s):  
Natural Rubber ◽  
Raw Materials ◽  
Research Work ◽  
Damping Properties ◽  
Main Research ◽  
Functional Additives ◽  
Different Types ◽  
Elastomeric Materials ◽  
Research Goal ◽  
The Impact

Increasingly, raw materials of natural origin are used as fillers in polymer composites. Such biocomposites have satisfactory properties. To ensure above-average functional properties, modifications of biofillers with other materials are also used. The presented research work aimed to produce and characterize elastomeric materials with a straw-based filler and four different types of montmorillonite. The main research goal was to obtain improved functional parameters of vulcanizates based on natural rubber. A series of composites filled with straw and certain types of modified and unmodified nano-clays in various ratios and amounts were prepared. Then, they were subjected to a series of tests to assess the impact of the hybrids used on the final product. It has been shown that the addition of optimal amounts of biofillers can, inter alia, increase the tensile strength of the composite, improve damping properties, extend the burning time of the material and affect the course of vulcanization or cross-linking density.

Mechanical behaviour of powders using a medium pressure flexible boundary cubical triaxial tester

2003 ◽  
Vol 217 (3) ◽  
pp. 233-241 ◽  
Author(s):  
F Li ◽  
V M Puri
Keyword(s):  
Shear Modulus ◽  
Mechanical Behaviour ◽  
Triaxial Compression ◽  
Three Dimensional ◽  
Volumetric Strain ◽  
Confining Pressure ◽  
Alumina Powder ◽  
Medium Pressure ◽  
Mean Pressure ◽  
Confining Pressures

A medium pressure (<21 MPa) flexible boundary cubical triaxial tester was designed to measure the true three-dimensional response of powders. In this study, compression behaviour and strength of a microcrystalline cellulose powder (Avicel® PH102), a spray-dried alumina powder (A16SG), and a fluid-bed-granulated silicon nitride based powder (KY3500) were measured. To characterize the mechanical behaviour, three types of triaxial stress paths, that is, the hydrostatic triaxial compression (HTC), the conventional triaxial compression (CTC), and the constant mean pressure triaxial compression (CMPTC) tests were performed. The HTC test measured the volumetric response of the test powders under isostatic pressure from 0 to 13.79MPa, during which the three powders underwent a maximum volumetric strain of 40.8 per cent for Avicel® PH102, 30.5 per cent for A16SG, and 33.0 per cent for KY3500. The bulk modulus values increased 6.4-fold from 57 to 367MPa for Avicel® PH102, 3.7-fold from 174 to 637 MPa for A16SG, and 8.1-fold from 74 to 597MPa for KY3500, when the isotropic stress increased from 0.69 to 13.79 MPa. The CTC and CMPTC tests measured the shear response of the three powders. From 0.035 to 3.45MPa confining pressure, the shear modulus increased 28.7-fold from 1.6 to 45.9MPa for Avicel® PH102, 35-fold from 1.7 to 60.5MPa for A16SG, and 28.5-fold from 1.5 to 42.8MPa for KY3500. In addition, the failure stresses of the three powders increased from 0.129 to 4.41 MPa for Avicel® PH102, 0.082 to 3.62 MPa for A16SG, and 0.090 to 4.66MPa for KY3500, respectively, when consolidation pressure increased from 0.035 to 3.45MPa. In addition, the shear modulus and failure stress values determined from the CTC test at 2.07, 2.76, and 3.45MPa confining pressures are consistently greater than those from the CMPTC test at the same constant mean pressures. This observation demonstrates the influence of stress paths on material properties. The CTT is a useful tool for characterizing the three-dimensional response of powders and powder mixtures.

Adhesives for the Installation of Cast Basalt Elements on Metal and Comparison of Properties when Using Different Types of Fillers

2021 ◽  
Vol 898 ◽  
pp. 35-41
Author(s):  
Jakub Hodul ◽  
Tomáš Žlebek ◽  
Lenka Mészárosová ◽  
Aleš Jakubík ◽  
Rostislav Drochytka
Keyword(s):  
Construction Industry ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Mineral Admixtures ◽  
Maximum Efficiency ◽  
Organic Additives ◽  
Metal Base ◽  
Secondary Raw Materials ◽  
Ecological Benefit ◽  
Different Types

The polymeric adhesives for the installation of basalt elements on a metal base are designed primarily for environments with increased chemical and mechanical stress. They are composed of polymer resins (epoxy, polyurethane) as binders, as well as organic additives and mineral admixtures that mainly fulfill the function of filler. In all sectors of today's construction industry, maximum efficiency in the production of materials is required for sustainability purposes, which, however, must never be at the expense of the quality or the required performance. Due to these requirements, great emphasis is placed on the maximum use of secondary raw materials. Talc is used as the primary filler for polymer adhesives. Sawdust, tire rubber, and fly ash are used as secondary raw materials. The use of these in building supplies can positively affect some physical and mechanical properties of polymeric adhesives. Also, the use of secondary raw materials has the above-mentioned ecological benefit. Basic properties, such as bulk density and adhesion to both metallic and basalt elements, were monitored. The details of the cohesion of the adhesive with the bonded material, as well as the distribution of secondary raw materials in the polymer matrix, were assessed microscopically.

scholarly journals Characteristic of materials for the 3D printed building constructions by additive printing

2018 ◽  
Vol 222 ◽  
pp. 01013 ◽  
Author(s):  
Katarzyna Pacewicz ◽  
Anna Sobotka ◽  
Łukasz Gołek
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
New Technology ◽  
Setting Time ◽  
Three Dimensional ◽  
Construction Site ◽  
Printing Technology ◽  
Three Dimensional Printing ◽  
Materials Used ◽  
Dimensional Printing

Three dimensional printing is a promising new technology to erect construction objects. Around the world in every moment a new prototypes constructions are made by using this method. Three dimensional printing is taken into account as technology which can be used to print constructions in automated way on the Moon or Mars. The raw materials, which can be used with three dimensional printing have to fulfil basic requirements for those which are used in construction. That means that components of printing mortars are made from ingredients easily accessible in area nearby construction site and can be reusable. The cost of printing building objects due to that requirements is comparable to costs of traditional building, which are currently available. However additive techniques of printing needs a dedicated mortars for printer supplying. Characteristic for such mortars is: setting time, compressive strength, followability in the printing system, shape stability of every printed layer, controlling the hydration rate to ensure bonding with the subsequent layer, reusable capabilities, easily accessible raw materials, cost of such mixtures shouldn’t be too high in order to keep 3D printing competitive for traditional ways of building, mortar components should be recyclable and printing process should not influence negatively on an environment and people. All properties of printing mortars are determined by the device for additive application method. In this paper review of available materials used for three dimensional printing technology at construction site is presented. Presented materials were analysed in terms of requirements for building materials technology. Due to the lack of detailed information’s in available literature, regarding to the properties of raw materials, the results of this analysis may be used in the designing of new concrete mixtures for the use in three-dimensional printing technology for construction.

Creep behavior in Virginia Beach sand

2013 ◽  
Vol 50 (11) ◽  
pp. 1159-1178 ◽  
Author(s):  
Hamid Karimpour ◽  
Poul V. Lade
Keyword(s):  
Triaxial Compression ◽  
Initial Response ◽  
Grain Structure ◽  
Beach Sand ◽  
Static Fatigue ◽  
Compression Tests ◽  
Time Effects ◽  
Grain Crushing ◽  
Virginia Beach ◽  
Confining Pressures

Triaxial compression tests were performed on dense specimens of Virginia Beach sand at low and high confining pressures to study time effects that relate to grain crushing due to static fatigue or delayed fracture. Experiments to study effects of loading strain rate on subsequent creep showed negligible time effects and no grain crushing at low confining pressures, while tests at high confining pressures indicated increasing amounts of creep with increasing initial loading strain rates and with increasing deviator stress at creep. Investigation of effects of grain-size distribution indicated stiffer initial response and smaller amounts of creep for more uniformly graded soils at high confining pressures. The experimental results showed that structuration effects were not present in the dense Virginia Beach sand. A long-term creep test at high confining pressure indicated continuous creep with no indication of its termination. Sieve analyses following each triaxial test showed that grain crushing, as quantified by Hardin’s relative breakage factor, was proportional to energy input and amount of creep observed for each soil specimen. The creep is due to the time-dependent static fatigue by which the grains crush and cause rearrangement of the grain structure, and this is the reason behind the time effects in granular materials.

scholarly journals Early-Age Cracking in Concrete: Causes, Consequences, Remedial Measures, and Recommendations

2018 ◽  
Vol 8 (10) ◽  
pp. 1730 ◽  
Author(s):  
Md. Safiuddin ◽  
A. Kaish ◽  
Chin-Ong Woon ◽  
Sudharshan Raman
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Real Life ◽  
Early Age ◽  
Structural Elements ◽  
Remedial Measures ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Different Types ◽  
Service Conditions

Cracking is a common problem in concrete structures in real-life service conditions. In fact, crack-free concrete structures are very rare to find in real world. Concrete can undergo early-age cracking depending on the mix composition, exposure environment, hydration rate, and curing conditions. Understanding the causes and consequences of cracking thoroughly is essential for selecting proper measures to resolve the early-age cracking problem in concrete. This paper will help to identify the major causes and consequences of the early-age cracking in concrete. Also, this paper will be useful to adopt effective remedial measures for reducing or eliminating the early-age cracking problem in concrete. Different types of early-age crack, the factors affecting the initiation and growth of early-age cracks, the causes of early-age cracking, and the modeling of early-age cracking are discussed in this paper. A number of examples for various early-age cracking problems of concrete found in different structural elements are also shown. Above all, some recommendations are given for minimizing the early-age cracking in concrete. It is hoped that the information conveyed in this paper will be beneficial to improve the service life of concrete structures. Concrete researchers and practitioners may benefit from the contents of this paper.

scholarly journals Proposal for improved mixes to produce concrete masonry units with commonly used aggregates available in the Valley of Mexico

2017 ◽  
Vol 7 (1) ◽  
pp. 36-56
Author(s):  
A. Tena ◽  
A. Liga ◽  
A. Pérez ◽  
F. González
Keyword(s):  
Mexico City ◽  
Raw Materials ◽  
Federal District ◽  
Masonry Structures ◽  
Construction Site ◽  
Test Results ◽  
Concrete Masonry ◽  
Distrito Federal ◽  
Design Value ◽  
Masonry Units

Proposal for improved mixes to produce concrete masonry units with commonly used aggregates available in the Valley of MexicoABSTRACTIn this paper, a proposal is done to update the masonry index compressive strength design value f*m for solid concrete masonry units for the masonry guidelines of Mexico´s Federal District Code (NTCM-2004). Solid units were made by taking into account the characteristics of the most commonly used raw materials available in the Valley of Mexico to fabricate such units in the Metropolitan Area of Mexico City. Different tests were conducted for both raw materials and the obtained concrete units. Based upon test results, it is illustrated why it is much better to design masonry structures based upon the experimental data of the units to be used at the construction site rather than using index values proposed in building codes.Keywords: masonry; concrete masonry units; compressive strength.Propuesta de mejora de mezclas para producir piezas de mampostería de concreto empleando materiales comúnmente disponibles en el Valle de MéxicoRESUMENSe presenta un estudio donde se hace una propuesta para actualizar los valores índices de la resistencia a la compresión de mamposterías (f*m) elaboradas con piezas de concreto especificados en las normas de mampostería vigentes en el Distrito Federal. Se realizó un estudio de mercado, donde se tomaron en cuenta las características de los materiales comúnmente utilizados en la actualidad en el Valle de México para la fabricación de piezas de concreto sólidas, incluyendo los resultados de distintas pruebas de laboratorio realizadas a la materia prima. Con base en estos resultados, se ilustran las ventajas de diseñar a la mampostería con base experimental en lugar de utilizar los valores indicativos que se ofrecen en las normas de mampostería.Palabras clave: mampostería; piezas de concreto; resistencia a la compresión. Proposta de melhoria de traços para produzir blocos de alvenaria de concreto utilizando materiais comumente disponíveis no Vale do México RESUMOApresenta-se um estudo onde se propõe uma atualização dos valores do índice de resistência à compressão da alvenaria (f*m) elaborados com blocos de concreto especificados nas normas de alvenaria em vigor no Distrito Federal. Foi realizado um estudo de mercado, que levou em conta as características dos materiais comumente utilizados atualmente no Vale do México para a fabricação de blocos de concreto sólidos, incluindo os resultados de vários testes de laboratório nas matérias-primas disponíveis. Com base nestes resultados, são apresentadas as vantagens de projetar a alvenaria com base experimental em lugar de usar os valores indicativos oferecidos nas normas de alvenaria.Palavras chave: alvenaria; blocos de concreto; resistência à compressão.

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