Fabrication of Novel Aerated Concrete Blocks By Combining Traditional and Synthetic Materials

The demand for green construction materials is growing worldwide for environmental protection reasons. The majority of CO₂ emissions come from the concrete and construction sectors, which use natural resources for manufacturing. It also gives alarming notes on sustainability objectives. Since ancient times, the use of lime-based building materials has been practised. The lime mortar was prepared by mixing different natural additives (such as molasses, curdling, and egg yolk), which help in gaining strength as the lime mortar has less strength than the cement mortar, but it is more durable than the cement mortar. Many heritage monuments of the Indus Valley civilization made of lime mortar attest to the durability of lime-based structures. Lime-based mortar is still used in rural and suburban areas of India, along with other locally viable reinforcing materials like rice husk and tree barks. Although the prepared building material is eco-friendly enough, it still has a higher dead weight and some durability issues (e.g. higher water absorption). Here, we discuss the surface treatment of the waste polyethylene bag cuts, which have a higher potential for littering, using the traditional building material lime (usually used as the main binding material). Thus, lime-coated polyethylene bag cuts were prepared. When those lime-coated polymeric wastes were employed in wet, aerated cement-based slurry, they offered higher performance in fibre-matrix bonding than that of the untreated polyethylene bag cuts. Additionally, we used an eco-friendly aeration technique that required lesser energy than the presently available aeration techniques (i.e., an aluminium powder-based method). Colloidal gas aphrons (CGAs), which are micron-sized bubbles, are introduced as an aerating medium in this novel technique. The resultant aerated blocks possess low densities, moderate [1.95–3 MPa] compressive strengths, absorb less water, and are less prone to cracking due to the bridging effect of the plastic bag cuts. We were successful in using fly ash, another waste, during the preparation of the aerated slurry, which reduces the need for cement, main binder, and lowers the carbon impact. Thus, by using waste materials, these innovative reinforced aerated blocks would be able to achieve sustainability while also improving the characteristics of aerated blocks.