AN EXPERIMENTAL INVESTIGATION ON PLASTIC AND DEMOLISHED WASTE AS A PARTIAL REPLACEMENT IN CONCRETE MIX

Abstract

This study is mainly concerned with conducting experimental investigation for testing the suitability of plastic and demolished waste as a partial replacement in concrete mix. In the present scenario, no construction activity can be imagined without using concrete. Concrete is the most widely used building material in construction industry. As it is widely used for construction of various structures, the economy is dependent upon the cost of material used in making concrete. On the other hand, due to rapid urbanization and industrialization all over the world, huge quantities of plastic waste and demolished waste are being generated. The disposal of these wastes is a very serious problem because, it requires huge space and also it causes environmental pollution. In this situation, construction industry is in need of finding cost effective materials for increasing the strength of concrete. So, in this project it is dealt with the possibility of using the plastic waste and demolished waste as the partial replacement of fine aggregate and coarse aggregate in concrete mix. In this perspective, it is aimed at comparing the properties of conventional concrete mix with the concrete mix prepared using plastic waste and demolished aggregate. In the present experimental investigation, plastic waste is used as replacement of fine aggregate partially by 10% and coarse aggregate is replaced with demolished aggregate partially by 0%, 10%, 20%, 30%, 40% and 50%. The conventional mix has been designed for C-25 grade concrete. In this investigation seven mixes are prepared; the specimens used are cubes of size 150mm length, 150mm width and 150mm depth, cylinders of size 150mm diameter and 300mm of height and flexural beam moulds of size 500mm length, 150mm width and 150mm depth. v Initially, conventional mix is prepared by using conventional materials (cement, natural sand, natural aggregate and water) and their physical and mechanical properties were evaluated. Now, the concrete with recycled wastes are prepared and these are also tested for their properties, likewise all the seven mixes were prepared. For every mix 18 specimens (6 cubes, 6 cylinders, 6 flexural beam specimens) were casted and thus totally 126 specimens were prepared. Specimens of every mix were tested for compressive strength, splitting tensile strength and flexural strength test at 7 and 28 days after curing. With constant percentage replacement of plastic waste in place of sand and varying percentage replacement of coarse aggregate with demolished aggregate, it is found that the density of concrete can be varied from 2500 to 2100 kg/m3. The workability of fresh concrete was decreased with increase in addition of recycled aggregate. From the results it is found that by replacing the natural sand and coarse aggregate by plastic waste and recycled aggregate in the normal concrete, compressive strength (fck), split tensile strength (ft) and flexural strength decreases with increase of recycled wastes. From the experimental investigation, it is concluded that fine aggregate replaced with 10% of plastic waste and coarse aggregate replaced with 10% of recycled aggregate, the properties of fresh concrete were good and also it reached the target mean strength of conventional concrete.