Executive Summary : | Usage of biomedical plastic waste as aggregates in concrete has intense potential to deal with the huge plastic wastes and the consequential ecological risks. However, research findings of last decades indicate poor compressive strength and workability of such concrete. The proposition submitted aims to address this issue. The hypothesis is columnar shape plastic aggregates, embedded with sand / Silica nano particles can offer desired strength and workability to the concrete. The poor performance in concretes prepared using plastic based aggregates was attributed to shape, smoothness and hydrophobic nature of the plastic aggregates. The flaky shapes enhance inter aggregate friction and spherical shapes promote air entrapment and voids. The smooth surface causes weak bond formation at transition zones. The hydrophobic nature results in poor water absorption. The proposed treatment can address concerns raised. The packing fraction in the columnar grains is less compared to the spherical grains having a potential to reduce porosity. This necessitates appropriate mathematical modeling to determine the dimensions as well as aggregate mixing order. In the proposed treatment the plastic wastes after decontamination will be molded and embedded with suitable percentage of sand and Silica nanoparticles. The sand/SNP based surface layer will offer the appropriate substrate for the bond formation thus mitigating the challenges. Laboratory scale experiments undertaken by the proposer has yielded promising results enhancing the compressive strength up to 29 MPa in contrast to 20 MPa strength of concrete prepared using untreated aggregates. An extensive research is necessary to understand the concrete behavior for fresh properties, hardened properties, durability study. In the research we have proposed to design the aggregate through modeling and experimentation. The parameters including columnar aggregate dimensions, sand/SNP ratio, embedded surface coverage will be varied within modeled ranges to produce coarse aggregates. Concretes will be prepared using the modified coarse aggregates as part replacement of coarse aggregates at different levels from 10% to 30%. The proposed research is estimated to be completed in two and half years and involves financial estimates of 20 lakhs. The research results are expected to open up an adoptable avenue towards using vast quantity of biomedical plastic wastes. The research will necessitate mechanical processing, plastic processing and concrete processing. The proposing team has research experience in all these domains. Though the research aims at using biomedical waste plastics, the outcomes will add knowledge in the direction of using general plastics and geopolymer concretes. |