Use of Polyethylene Terephthalate Fibers for Strengthening of Reinforced Concrete Frame Made of Low-Grade Aggregate

This chapter presents an experimental finding on the use of waste materials for strengthening a reinforced concrete (RC) frame prepared with low-grade materials. Compressive, tensile and flexural strength of concrete specimens made of recycled coarse aggregate (RCA) and natural coarse aggregate (NCA) were evaluated to assess RCA suitability for structural use. Results show that the strength parameter decreases in all cases. In order to extend the application of RCA concrete to structural elements, three RC frames were prepared and tested under monotonic loading. The joint regions of one of the frame were cast using Polyethylene terephthalate (PET) fiber, i.e., PET fiber-reinforced concrete (PFRC). PET fiber (aspect ratio = 25) of 0.5% by weight of concrete used in the PFRC mix was obtained by hand cutting of post-consumer PET bottles. A reference specimen was also prepared using 100% NCA and subjected to a similar loading condition. The RCA frame resulted in a brittle mode of failure and lower load carrying capacity as compared to the reference specimen. However, the presence of PFRC improved the damage tolerance and load resisting capacity and hence seismic parameters such as stiffness degradation, ductility and energy dissipation increased. This indicates that PET fiber is a viable substitute for steel fiber as a low-cost material in improving the seismic performance of frame structures

Analysis of Material Removal and Surface Characteristics in Machining Multi Walled Carbon Nanotubes Filled Alumina Composites by WEDM Process

The reinforcement of ceramic materials with electrically conductive particles increases the overall conductivity of the ceramic material. This allows the ceramic material to be more readily machined using wire electrical discharge machining process. The current work is an approach to identify the machinability of multi walled carbon nanotubes filled alumina composites in wire electrical discharge machining process. Alumina samples of 5 vol. % and 10 vol. % multi walled carbon nanotubes are machined and analysed for material removal rate and the surface characteristics. An increase in material removal rate is observed with increase in filler concentrations. At the same time, better surface roughness is observed. The surface characteristics of composite alumina are further compared with Monel 400 alloy. It has been observed that spalling action is the dominating material removal mechanism for alumina composites, while melting and evaporation is for the Monel 400 alloy

A few simple CFD models for flow simulation around groyne

The flow processes around a groyne structure is a complex and challenging topic in computational hydraulics and has brought attention of many researchers in the last few decades. In comparison to experimental studies, numerical modeling can provide more details about the flow characteristics at less cost. In the present work, performances of four simple finite difference schemes, i.e., Lax diffusive scheme, predictor corrector scheme, modified predictor corrector scheme and Beam and Warming scheme are compared in simulation of flow around groyne structure. The numerical results are validated with available experimental data and the best model is found out in terms of accuracy and efficiency