International Journal of Science, Engineering and TechnologyAuthors: D.Ramakrishna, Dr.Ala Satyanarayana
Abstract: Concrete is one of the most widely used construction materials and is generally produced using large quantities of natural sand and crushed stone aggregates. Nearly 65–70% of the volume of conventional concrete consists of these natural materials. As a result, the concrete industry places considerable demand on natural resources. With the growing emphasis on sustainable construction, there is a need to reduce the dependence on conventional aggregates by incorporating suitable waste materials into concrete. Materials such as waste glass and discarded polyethylene terephthalate (PET) bottles can potentially serve as alternative aggregates when used at appropriate replacement levels without significantly affecting the required mechanical performance of concrete. The use of glass products has increased considerably in residential and commercial buildings. Glass is commonly used in windows, partitions, interior decoration, furniture, façades and architectural finishes because of its aesthetic and functional advantages. However, its brittle nature results in a substantial quantity of waste during manufacturing, transportation, cutting, handling and installation. A large portion of this waste is often discarded rather than reused, creating disposal and environmental concerns. Similarly, PET, or polyethylene terephthalate, has become one of the most commonly used plastics, particularly for beverage and water bottles. PET bottles are preferred because of their relatively high strength, low density, durability, good appearance and low permeability to gases such as carbon dioxide. The rapid increase in the consumption of PET products has consequently resulted in a significant increase in plastic waste. In many regions, the amount of PET waste generated is considerably higher than the quantity that is recycled. Disposal of such waste in landfills creates long-term environmental problems because plastics degrade very slowly. Therefore, utilizing waste glass and PET materials as partial substitutes for conventional aggregates in concrete can offer a practical method of waste management while also reducing the consumption of natural resources. The present experimental investigation was carried out in different stages to evaluate the possibility of using waste glass and PET bottle waste as aggregate replacements in M40 and M70 grade concrete. In the initial stage, waste glass was introduced separately as a replacement for fine aggregate, coarse aggregate and as a combined replacement for both fine and coarse aggregates. Different replacement percentages were investigated in order to determine the proportion that produced the most suitable compressive strength. A similar procedure was followed for PET bottle waste. Based on the results obtained from these preliminary trials, optimum replacement levels were selected for both M40 and M70 concrete. The confinement index was therefore closely associated with the improvement in the axial response of the concrete specimens. In addition, the stress ratio, strain ratio and ductility factor showed an increasing trend with higher levels of confinement. Overall, the study demonstrates that selected quantities of waste glass and PET bottle waste can be incorporated into M40 and M70 concrete as partial replacements for natural aggregates. When combined with suitable lateral confinement, the resulting concrete can exhibit improved strength and deformation characteristics. This approach provides a useful means of recycling non-biodegradable waste, reducing the consumption of natural aggregates and promoting more sustainable concrete construction.
DOI: http://doi.org/10.5281/zenodo.23180861
