## 4 Conclusions  
This paper reported the results of an experimental study conducted to investigate and evaluate fresh and hardened properties of high-strength concrete containing three types of BPW, hybrid, hard, and soft, to address a current lack of knowledge of employing this concrete for engineering purposes and pave the way towards the utilisation of biomedical waste in structural concrete as a sustainable way of their disposal. The following main concluding remarks can be drawn:  
* Generally, including hard or hybrid BPW in concrete results in better properties than soft BPW-containing concrete. * The more BPW addition leads to more reduction in the slump by up to 46.4%, 54.4%, and 48.8% after adding up to 9% hybrid, hard, and soft BPW, respectively. It can be attributed to the flaky and elongated shapes of the BPW particles, affecting the workability factors due to more friction and lower flowability. * Incorporating BPW causes the density of the concrete to decrease by up to 2.08%, 2.17%, and 2.04% regarding hybrid, hard, and soft BPW, respectively. * The compressive strength of all types of BPW-containing high-strength concrete is lower than the non-BPW-containing concrete, which can be attributed to a weaker cohesion and friction at the ITZ of BPW and the cement paste compared to the natural aggregate. The compressive strength declines gradually by BPW addition up to 9% hybrid, hard, and soft BPW by 38.08%, 33.9%, and 41.16%, respectively. Figure 20: Experimental modulus of elasticity of the concrete containing BPW versus predicted values obtained from the Equation (3), and correction factors for each type of BPW. * The tensile strength of the BPW-containing concrete decreases by adding more BPW by up to 14.9%, 14.16%, and 20.62% for hybrid, hard and soft BPW, respectively. However, at small amounts of BPW addition, the tensile strength reduction is marginally the same as the non-BPW-containing concrete. * Addition of BPW leads the modulus of elasticity to decrease by up to 27.41%, 24.4%, and 33.19% for hybrid, hard, and soft BPW-containing concrete respectively, which can be attributed to the lower modulus of elasticity of the DWP than natural aggregate and more porous ITZ between the BPW and the cement paste. * The structural and physical properties of BPW-containing concrete generally follow the same models used in most conventional concrete codes, i.e., a power relationship is observed between f\({}_{\text{t}}\) and f\({}_{\text{c}}\), and E and f\({}_{\text{c}}\). Predictions by ACI 363-R08 [68], ACI 318-14 [76], AS 3600-2018 [16], and EC-2 [69] are better matched with the results of this study. * Comparing with other formulae proposed for the tensile strength of plastic-containing concrete, results of this study are in good agreement with [PERSON] et al. [19] and [PERSON] (coarse aggregate substitution) [35]. However, they utilised quite different types and shapes of polymeric materials. * Given the difficulties involved in measuring the modulus of elasticity, and following several codes [16; 68; 74; 76; 81], a regression-based formula was proposed to predict the elastic modulus of BPW-containing concrete based on its density and compressive strength. Given that the essential mechanical properties of structural concrete containing a small percentage of hybrid BPW are predictable by current codes for normal concrete, and noting that preparing hybrid BPW does not need any manual procedure, adding BPW in concrete seems to be a viable solution to decrease the landfilling problem caused by medical waste. S.R. : Methodology, Investigation, Writing--Original Draft; K.G. : Supervision, Writing--Review and Editing; E.O.G. : Supervision, Writing--Review and Editing; R.A.-A. : Supervision, Writing--Review and Editing. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable.