Ahmed Wisal, Lim C W
Department of Architecture and Civil Engineering, City University of Hong Kong, Kowloon, Hong Kong Special Administrative Region.
City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, PR China.
Constr Build Mater. 2022 Aug 15;344:128245. doi: 10.1016/j.conbuildmat.2022.128245. Epub 2022 Jun 27.
Global public response to the COVID-19 (SARS-CoV-2) pandemic is highly focused on human health. However, conservationists have cautioned of unprecedented threats to the natural environment from a new type of non-biodegradable microplastic waste resulting from extensive use of disposable medical face masks (DMFMs). Thus, this waste must be recycled in an eco-friendly manner on an urgent basis. In this research, we developed a new environmentally friendly recycling technique using waste DMFMs in sustainable green concrete. More explicitly, a new fiber hybridization approach has been introduced in which two types of fibers namely DMFM fiber and basalt fiber (BF) were incorporated into fiber reinforced recycled aggregate concrete (FRAC). The volume fractions of DMFM fiber were 0%, 0.1%, and 0.2% and the volume fractions of BF were 0%, 0.25%, and 0.5%. In addition, two mineral admixtures (fly ash and ground granulated blast furnace slag) were also used. Test results indicated increase of approximately 12% in compressive strength, 26% in split tensile strength, and 60% in flexural strength of FRAC containing hybrid fibers and mineral admixtures. The density and ultra-sonic pulse velocity (UPV) of DMFM fiber- and BF-modified FRAC ranged from 2406-2433 kg/m and 4502-4541 m/s, respectively, which meets structural concrete requirements. The water absorption rate gradually increased with an increase in the volume fractions of fibers but remained within the allowable water absorption limit for construction materials. Lastly, the microstructure investigation indicated excellent concrete quality, improved interfacial transition zones (ITZs), and good compatibility of host concrete matrix with both DMFM fiber and BF that correlates well with the experimental results reported in this study.
全球对新冠疫情（严重急性呼吸综合征冠状病毒2）的公共应对高度关注人类健康。然而，自然资源保护主义者警告称，一次性医用口罩（DMFM）的大量使用产生了一种新型不可生物降解的微塑料垃圾，这对自然环境构成了前所未有的威胁。因此，必须立即以环保方式对这种垃圾进行回收利用。在本研究中，我们开发了一种新的环保回收技术，将废弃的DMFM用于可持续绿色混凝土中。更确切地说，引入了一种新的纤维混杂方法，将两种类型的纤维，即DMFM纤维和玄武岩纤维（BF）掺入纤维增强再生骨料混凝土（FRAC）中。DMFM纤维的体积分数分别为0%、0.1%和0.2%，BF的体积分数分别为0%、0.25%和0.5%。此外，还使用了两种矿物掺合料（粉煤灰和粒化高炉矿渣）。试验结果表明，含有混杂纤维和矿物掺合料的FRAC的抗压强度提高了约12%，劈裂抗拉强度提高了26%，抗弯强度提高了60%。DMFM纤维和BF改性的FRAC的密度和超声波脉冲速度（UPV）分别为2406 - 2433 kg/m和4502 - 4541 m/s，符合结构混凝土的要求。吸水率随着纤维体积分数的增加而逐渐增加，但仍在建筑材料允许的吸水率范围内。最后，微观结构研究表明混凝土质量优异，界面过渡区（ITZ）得到改善，主体混凝土基体与DMFM纤维和BF的相容性良好，这与本研究报告的实验结果高度相关。
