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Compared to conventional concrete, lightweight concrete offers a reduced unit weight, making it easier to handle and transport. Its popularity has surged globally in numerous countries and has proven beneficial for construction purposes. Lightweight concrete often exhibits better thermal insulation properties compared to traditional concrete, contributing to energy efficiency in buildings. Recently, the inclusion of cenospheres in lightweight aggregates is being is heavily researched around the world. Ceneosphere addition increases the volume of the concrete mixture because of their smaller size and hollow nature of the particle. This research paper showcases the various applications and advantages of lightweight concrete (LWC) containing cenosphere, along with highlighting the role of different supplementary cementitious materials characteristics and manufacturing methods. Furthermore, the current study examines previous researches on sustainable lightweight concretes and showcases the improvements and advancements in mechanical, durability, and thermal properties obtained when cenospheres were added.

Concrete’s thermal properties are more complex than for most materials because not only is the concrete a composite material whose constituents have different properties, but its properties also depend on moisture and porosity. Exposure of concrete to elevated temperature affects its mechanical and physical properties. In the current study, M40 and M80 grades of plain self-compacting concrete (SCC) mixes are developed using Nan Su mix design principles to investigate the effect of elevated temperatures on 1) weight and compressive strength 2) compressive strength of SCC when tested cool and hot 3) effect of 2, 4 and 6 hrs. exposure duration of elevated temperatures on compressive strength 4) modulus of elasticity 5) size of testing specimen and 5) effect of thermal cycles on SCC mixes. Results derived the following conclusions 1) the M80 specimens lose more strength than M40 SCC specimens when subjected to elevated temperatures ;2) specimens heated and then permitted to cool before testing lose more strength than those tested while hot; 3) the longer the duration of heating before testing, the larger the loss in strength; 4) The decrease in modulus of elasticity caused by elevated-temperature exposure is more pronounced than the decrease in compressive strength. 5) Small test specimens generally incur greater strength losses than larger ones and 6) Specimens subjected to several cycles of heating and cooling lose more strength than those not subjected to thermal cycling.

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Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study deals with thermal and mechanical modelling of plasma sprayed zirconia coatings on stainless steel substrates, with a NiCrAlY bond coat. Applications concern thermal barrier coatings (TBC). Typically a coating of some hundreds micrometers induces a decrease of some hundreds degrees on the substrate temperature following the thermal flux. NiCrAlY permits to regularise the gap of the dilatation coefficients between the substrate and the ceramic. The NiCrAlY improves the adhesion of the coatings by providing a transition between the level of residual stresses in the three layers. A numerical model is developed and integrated to the industrial code ABAQUS based on finite elements approximation to simulates these behaviours under a parametric study. [ABSTRACT FROM AUTHOR]

The applied thermo-mechanical loading during cutting process leads to an important tool failure especially when machining is effected on refractory super-alloys such as titanium and/or nickel based-alloys. Heat removal generated by tool/workpiece friction plays an important role in preserving the structural integrity of the cutting tool. Efficient heat removal in machining depends solely on the thermal properties of the tool and on their evolution with temperature and mechanical parameters (strain, strain rate, etc.). In the present work, the effect of these thermal properties on the produced wear during the machining of refractory alloys is particularly investigated. Finite-Element Analysis (FEA) and SEM-imagery were used to map the thermal conductivity within the affected tool zone. The results indicate that depending on the temperature rise, the tool-tip might undergo a severe drop in thermal conduction. This drop may locally restrict the ability of the tool material to dissipate the applied thermal load. This may nucleate thermally congested clusters within the tool-tip where the material completely loses the ability to transport heat. Thermal congestion renders an energetically active zone where the thermal energy available may be used to activate wear through different mechanisms. It is also found that the immediate layer under the surface of the tool tip is important to enhance the ability of the tool material to dissipate the thermal loads. The results also highlight the importance of matching the temperature dependant properties of the different coating layers in order to enhance delamination resistance. [ABSTRACT FROM AUTHOR]