American Journal of Materials Science 2016, 6(4A): 88-93 DOI: 10.5923/c.materials.201601.17 Taguchi Analysis on the Compressive Strength Behaviour of Waste Plastic-Rubber Composite Materials Noel Deepak Shiri * , Shreeranga Bhat, Babisha K. C., Krishna M. Moger, Minal Patricia D’almeida, Clyde Jofan Menezes Department of Mechanical Engineering, St. Joseph Engineering College, Mangaluru, India Abstract In this paper an attempt has been made to optimize the waste plastic-rubber composite materials using the Taguchi’s Design of Experiment Methodology. Moreover, an investigation has been carried to find out the effect of various parameters such as waste plastic mix, rubber powder, and filler materials (calcium carbonate and fly ash) on the compressive strength of the material. The main objective was to reutilize the waste plastics into developing plastic-rubber composite materials. In the present research, waste plastics have been blended with rubber powder, calcium carbonate, and fly ash in a plastic extruder. Then the melt was transferred into cube moulds, and rammed to form the specimens. Taguchi’s L9 orthogonal array has been utilized to perform the experiment, and to optimize the parameters. The samples have been subjected to compression tests on the Universal Testing Machine. The data obtained has been analyzed using MINITAB statistical software to draw the robust conclusion. SEM micrographs and Particle size analysis have been performed on the fly ash filler material. The results show that fly ash is a mixture of micro and nano sized particles with a wide range of particle sizes. Further, it is evident from the research that all the selected parameters like waste plastic, rubber powder, fly ash and calcium carbonate are having significant effect on the compressive strength of the material under study. The Analysis of Variance (ANOVA) revealed that waste plastic mix is the most influencing parameter for the compressive strength. Experimental results of compressive strength for optimum values of waste plastic-rubber composite material in comparison with clay brick revealed that it is 3 times stronger than the normal clay brick. These results indicate that waste plastic-rubber composite material could be used as low cost construction material and a cheaper substitute to clay bricks and various other building materials. Keywords Waste plastics, Plastic/Rubber composite, Plastic Extruder, Compression Testing, Taguchi’s Technique 1. Introduction Plastic is one of the most commonly used materials in the modern era mainly due to its versatility and durability. It has also made life easier and better, but it is also very hazardous when not properly managed. Due to its non-biodegradable nature it gets accumulated in the environment and causes a lot of problems [1]. Plastics are generally lightweight, non-corrosive, soft, flexible, not easily damageable. And its high heat and electrical insulation features make plastics an indispensable packaging material. Also plastics rank first in the total amount of global waste produced. Four percent of the oil produced in the world is used in the production of plastics. Plastics are mostly used in packaging and construction industries. Polyethylene (PE), Polypropylene (PP), Polyethylene Terephthalate (PET), Polyvinyl Chloride (PVC) and Polystyrene (PS) are the main types of plastics * Corresponding author: noelshiri.sjec@gmail.com (Noel Deepak Shiri) Published online at http://journal.sapub.org/materials Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved [2]. Waste plastics can be used for production of construction materials like building blocks, roof and floor tiles and also for bridge construction materials. This in turn optimises the problem of waste material storage and the high cost of building materials. The waste plastics are incorporated with sand and other additives to form the construction materials [3]. Plastic waste recycled in India is in an unorganized method and 60% of the plastic-waste collected and segregated gets recycled back into materials for further processing into consumer products, while the balance is left unutilized and it is a source of hazard to environment. Plastics account for 16% of chlorine in the environment and have 54 carcinogens. Polythene bags for disposal if burnt irresponsibly releases highly toxic gases like phosgene, carbon monoxide, chlorine, sulphur dioxide, nitrogen oxide, besides deadly dioxin. Polymer materials are steadily replacing natural materials like metal, timber and fibres and thus conserving the natural environment [4]. Using a waste plastic extruder, the method for effectively converting waste plastics into building materials like bricks and interlocks have been studied and the plastic brick obtained was shown