Improvement in mechanical properties of SBR/Fly ash composites by in-situ grafting-neutralization reaction

This research investigates the preparation and characterization of new organic–inorganic geopolymeric foams obtained by simultaneously reacting coal fly ash and an alkali silicate solution with polysiloxane oligomers. Foaming was realized in situ using Si0 as a blowing agent. Samples with density ranging from 0.3 to 0.7 g/cm3 that show good mechanical properties (with compressive strength up to ≈5 MPa for a density of 0.7 g/cm3) along with thermal performances (λ = 0.145 ± 0.001 W/m·K for the foamed sample with density 0.330 g/cm3) comparable to commercial lightweight materials used in the field of thermal insulation were prepared. Since these foams were obtained by valorizing waste byproducts, they could be considered as low environmental impact materials and, hence, with promising perspectives towards the circular economy.

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Flexural Performance of Geopolymer Concrete Modified with Pozzalonic Minerals and Secondary Reinforcement

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2018.7110 ◽

2018 ◽

Vol 15 (2) ◽

pp. 459-469

Author(s):

D. R. Anand Rejilin ◽

R. Murugesan ◽

V. Bravin Ebanesh

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Secondary Reinforcement ◽

Fibre Reinforcement ◽

Percentage Increase ◽

Cement Concrete ◽

Flexural Performance ◽

Micro Cracks ◽

Structural Applications

Concrete, the versatile building material is relevantly used for structural applications for its ease of application and in situ adaptability. Decline of raw materials, cost and environmental issues related to unsustainable usage of cement, persuades the construction industries for an alternate binder similar to cement. Geoploymer concrete known for its eco-friendly manufacturing process and economic approach makes the, GPC a viable substitute for cement concrete. At elevated temperature, GPC undergoes polymerisation reaction and develops three dimensional amorphous components which exhibits enriched mechanical properties. To achieve the in-situ application of geoploymer concrete and to overcome the requirement of heat during polymerisation reaction, fly ash based GPC was modified with different proportions of GGBS and OPC and curing it with ambient temperature for enhancing its mechanical behaviour. Variation in temperature during the initial stages of casting process produces micro cracks which are prevented by addition of Secondary reinforcements which furthermore improved the mechanical properties. A constant percentage of GUJCON fiber as secondary reinforcement was added to all the modified proportions. The fly ash based GPC replaced with GGBS and OPC showed improved split and compressive strength at 100% and 40%. Further improvement of strength was observed with 12% replacement of GGBS with OPC to GGBS based GPC. The flexural performance of the modified GPC with optimum proportions of GGBS and OPC was compared with conventional cement concrete beam. The percentage increase in strength of GGBS based GPC with optimum OPC content when compared with conventional specimens showed 53% improvement in strength. When fibre reinforcement was added in prescribed quantity, it promoted the mechanical strength and reduced micro cracks by which the load carrying capacity was increased to 66%. The structural performance of modified GPC was found to be suitable for in situ applications in ambient curing condition.

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Study on the Mechanical Properties of Fly-Ash-Based Light-Weighted Porous Geopolymer and Its Utilization in Roof-Adaptive End Filling Technology

Molecules ◽

10.3390/molecules26154450 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4450

Author(s):

Luchang Xiong ◽

Bowen Fan ◽

Zhijun Wan ◽

Zhaoyang Zhang ◽

Yuan Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Fly Ash ◽

Porous Structure ◽

High Efficiency ◽

Influence Factor ◽

Structure Model ◽

Plastic Yielding ◽

Working Face ◽

Secondary Air

This paper aims to study the porous structure and the mechanical properties of fly-ash-based light-weighted porous geopolymer (FBLPG), exploring the feasibility of using it in roof-adaptive end filling technology based on its in-situ foaming characteristics and plastic yielding performance. A porous structure model of FBLPG during both the slurry and solid period was established to study their influence factor. In addition, this study also built a planar structure model in the shape of a honeycomb with bore walls, proving that the bore walls possess the characteristics of isotropic force. FBLPG shows a peculiar plastic yielding performance in the experiment where its stress stays stable with the gradual increase of the deformation, which can guarantee the stability of a filling body under the cycled load from the roof. At the same time, the in-situ foaming process combined with the unique filling technique can make the FBLPG filling body fully in contact with the irregular roof. This roof-adaptive end filling technology makes it a successful application in plugging the 1305 working face, which avoids problems of the low tight-connection ratio and secondary air-leakage channel resulted from the traditional filling technology, effectively improving coal production in terms of safety and high efficiency.

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Dynamics of Nanoparticle Chain Aggregates of Carbon Under Tension

MRS Proceedings ◽

10.1557/proc-778-u4.4 ◽

2003 ◽

Vol 778 ◽

Author(s):

Rajdip Bandyopadhyaya ◽

Weizhi Rong ◽

Yong J. Suh ◽

Sheldon K. Friedlander

Keyword(s):

Mechanical Properties ◽

Carbon Black ◽

Polymer Film ◽

Elastic Behavior ◽

Small Strains ◽

Transmission Electron ◽

Chain Aggregates ◽

Nanoparticle Chains ◽

Reinforcing Filler

AbstractCarbon black in the form of nanoparticle chains is used as a reinforcing filler in elastomers. However, the dynamics of the filler particles under tension and their role in the improvement of the mechanical properties of rubber are not well understood. We have studied experimentally the dynamics of isolated nanoparticle chain aggregates (NCAs) of carbon made by laser ablation, and also that of carbon black embedded in a polymer film. In situ studies of stretching and contraction of such chains in the transmission electron microscope (TEM) were conducted under different maximum values of strain. Stretching causes initially folded NCA to reorganize into a straight, taut configuration. Further stretching leads to either plastic deformation and breakage (at 37.4% strain) or to a partial elastic behavior of the chain at small strains (e.g. 2.3% strain). For all cases the chains were very flexible under tension. Similar reorientation and stretching was observed for carbon black chains embedded in a polymer film. Such flexible and elastic nature of NCAs point towards a possible mechanism of reinforcement of rubber by carbon black fillers.

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