Khan M D Ikramullah, Ram V Vinayaka, Patel Vipulkumar Ishvarbhai
Department of Civil Engineering, Birla Institute of Technology and Science - Pilani, Hyderabad Campus, Secunderabad, Telangana, 500078, India.
School Computing, Engineering and Mathematical Sciences, La Trobe University, Bendigo, VIC, 3552, Australia.
Sci Rep. 2024 Jun 14;14(1):13776. doi: 10.1038/s41598-024-64506-6.
This study examines the effect of coarse recycled aggregates (CRAs) and processed coarse recycled aggregates (PCRAs) on the behaviour of alkali-activated concrete (AAC) before and after exposure to marine seawater and acidic environments (5% HCl and 5% HSO4 solutions). Measurements of compressive strength and the microstructure changes were conducted over periods of 56 and 90 days to assess these effects. The experimental design included varying the replacement levels of NAs with CRAs and PCRAs from (0-100%) and using ground-granulated blast furnace slag and fly ash as constant components. In addition to durability tests, sorptivity assessments were conducted to gauge the material's porosity and water absorption capabilities. Advanced microstructure techniques, such as scanning electron microscopy (SEM) and X-ray diffraction (XRD), were employed to detail the pre and post-exposure mineralogical and microstructural transformations within the AAC blends. The AAC mixtures incorporating PCRAs emerged as durable, showcasing better strength and a denser, more compact matrix facilitated by the synergistic formation of NASH and CASH gels after exposure to aggressive agents compared to untreated CRAs. In addition, the results show that the samples exposed to marine seawater exhibited improved mechanical performance compared to those exposed to acidic environments. The novelty of this study lies in its exploration of the effects of recycling plant-based CRAs and PCRAs on AAC for marine and acid exposure.
本研究考察了粗再生骨料（CRA）和加工粗再生骨料（PCRA）对碱激发混凝土（AAC）在暴露于海洋海水和酸性环境（5%盐酸和5%硫酸溶液）前后性能的影响。在56天和90天的时间内进行抗压强度测量和微观结构变化评估，以评估这些影响。实验设计包括将天然骨料（NA）用CRA和PCRA替代的水平从0至100%变化，并使用磨细粒化高炉矿渣和粉煤灰作为常量组分。除耐久性试验外，还进行了吸水性评估，以测量材料的孔隙率和吸水能力。采用了先进的微观结构技术，如扫描电子显微镜（SEM）和X射线衍射（XRD），来详细描述AAC混合料暴露前后的矿物学和微观结构转变。与未处理的CRA相比，掺入PCRA的AAC混合物表现出耐久性，在暴露于侵蚀性介质后，由于NASH和CASH凝胶的协同形成，展现出更好的强度和更致密、更紧凑的基体。此外，结果表明，与暴露于酸性环境的样品相比，暴露于海洋海水的样品表现出更好的力学性能。本研究的新颖之处在于探索了基于植物的CRA和PCRA对用于海洋和酸性暴露的AAC的影响。
