Epoxy fibers with different diameters were prepared by hot drawing and their mechanical properties were measured under tension. The stiffness, strength, ultimate strain, and toughness revealed substantial scale-dependent effects as they all significantly increased with a decrease in size. Compared to bulk epoxy, an intrinsically brittle material, thin epoxy fibers displayed a highly ductile behavior under tension. A drop in stress observed immediately beyond the yield point was followed by the development of a stable necking region propagating through the entire fiber length, then by strain-hardening up to final rupture. Necked fiber segments tested in tension were found to have even higher strength and modulus compared to the initial as-prepared fibers. Possible reasons for the highly ductile mechanical behavior and the size effects of epoxy fibers are discussed. Size effects for the strength of epoxy can be elucidated in principle either by means of a classical fracture mechanics argument (strength~1/d 1/2), or via a stochastic model argument (strength~1/d 1/β , where β is a function of the material and is generally larger than 2). In both models the presence and size of critical defects play a key role. However, defects cannot explain the colossal ductility (plastic deformation) seen in our experiments, nor can the presence of defects justify a size effect in an elastic property, namely Young's modulus. Only scarce evidence exists in the literature for similar (milder) size effects in epoxy fibers but without any structural justification. We find here that highly cross-linked necked epoxy fibers exhibit partial macromolecular anisotropy which likely explains the observed high mechanical characteristics.

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The use of plastic is considerably increased in day-to-day life for supply of the materials, liquids, foods and other essentials daily products. These single use plastic is disposed off in very disorderly manner. Therefore, the disposal of plastic waste becomes a universal problem because of it is non-biodegradable, and availability of plastic waste in huge quantity in the various countries having considerable population. This plastic waste can be reduced by utilizing in the same or in other forms in day-to-day various activities and development of infrastructure like cement concrete roads, pavements and other low cost housing schemes, but it is realize that all the plastic waste material cannot be reutilized. Its partial utilization may also become the solution to reduce the impact on the environment and ecological problems. The cost of ingredient concrete materials is continuously increasing due to non availability, taxation, transportation and also the wastes of materials. Therefore, the plastic waste can be converted into synthetic fibres and granules and can be utilize in concrete as a partial replacement of sand. The main objective of this laboratory investigation is to reduce the impact of plastic waste on the environment by utilizing in infrastructure development. For laboratory investigation, synthetic fibres 1%, 2% and 3% of dry weight of sand is utilized to replace the sand and plastic granules 5%, 10% and 15% of dry weight of sand is utilized to replace the sand. The strength parameters of concrete are tested in the laboratory such as compressive strength, tensile strength and workability of concrete. The test result shows positive impact of utilization of plastic waste up to some extent.

In present investigation, an attempt was made to optimise the peak stress for paper laminate composite using FRANC2D software. It was observed that the laminate having the triangular geometry supposed to be most appropriate as it has the lowest value of peak stress contour compared to other models like parallel strip, up-down tapered and down-up tapered. The minimum peak stress was observed for the samples having triangular geometry while the maximum was observed for down-up tapered samples. Therefore, the hypothesis adopted to use in-built materials with variables reinforcement area and strip geometry and length in the FRANC2D software to optimize the sample geometry and then apply it to the paper laminate by considering its mechanical properties might be use to optimize the peak stress of paper laminate composite in tensile loading conditions. It was also observed a length of one-quarter of the length of the plane strip, might be the optimum length of the paper laminate samples. However, it feels that, the above model can be further modified considering a more significant mechanical properties as well as different sample geometries.