A Termite-Inspired Alternative to Cement

Clay combined with organic materials is used by termites as a strong and durable construction material for their mounds with minimal environmental impact. Here, the bioinspired retrosynthesis of a composite is presented based on clay-cellulose-lignin as a sustainable, low-carbon alternative to ordinary Portland cement (OPC). It is shown that this green alternative has compressive strength comparable to that of OPC, 32 MPa, while maintaining the advantages of ambient-temperature processing (calcination temperatures >1400 °C are required for OPC). The higher compression strength of the green cement stems from a synergistic interaction between the stiff mineral and flexible cellulose fibers (as imaged by diverse advanced electron microscopy techniques), forming a dense interlocked network that enhances the strength and the elasticity of the composite. This is demonstrated by its ability to withstand repeated extreme compression cycles. These properties, together with ease of the process and the use of readily available materials of low environmental impact, positions the developed biocomposite as a promising construction material.