Nowadays, developing low-carbon building materials is urgently needed because of the massive energy consumption and carbon emissions from the tradition cement-based building materials production.  

Inspired by the colonial sandcastles, a research group led by Prof. WANG Shutao from the Technical Institute of Physics and Chemistry (TIPC) of the Chinese Academy of Sciences (CAS) have developed the natural-based low-carbon building materials which is promising to be applied in the next-generation low-carbon constructions. 

The work was published in Matter on Sept. 20.  

Usually, various adhesives, such as the geopolymers, resins, and high pressure-induced adhesives are used as the cement substitutes to fabricate the low-carbon building materials. Compared with these binders, the natural-based adhesives are promising due to the renewability and eco-friendliness of bio-resources.  

Tremendous research efforts have been devoted to binding grains by using bio-polymers as adhesives or bio-mineralization approaches. However, due to the weak mechanical properties of these grain aggregates, there are still limits in practical constructions. Developing the strong natural-based low-carbon building materials is therefore challenged but of great significance to reduce the carbon emissions and energy consumption in practical application. 

In this work, researchers found the in nature sandcastle worms can build up the strong colonial sandcastles as their nests along the coastlines. Because they bind various grains such as sands and shell pieces into their nest.  

Researchers realized the key point is the composite adhesive secreted by the sandcastle worms. The adhesive contains cationic proteins and anionic proteins simultaneously. It can bind the grains toughly.  

Mimicking this process, Prof. WANG’s group fabricated the colonial sandcastle-inspired low-carbon building materials with good mechanical performance. Based on the oppositely charged bio-polymer adhesives, these natural-based low-carbon building materials can be constructed by various grains (e.g., desert sands, sea sands, concrete slags etc.) under low temperature and atmospheric pressure.

Figure 1. (A) Design of colonial sandcastle-inspired natural-based low-carbon building materials. (B) Optical images of natural-based low-carbon building materials fabricated by various grains. (C) Comparison of compressive strength and elastic modulus between this natural-based low-carbon building materials and previous reported low-carbon building materials. 

The proposed natural-based low-carbon building materials possess anti-weathering property, waterproofness, unique recyclability. The designed new material is also exhibit great potential for next-generation low-carbon constructions. 

This work is supported by the National Natural Science Foundation of China and the International Partnership Program of the Chinese Academy of Sciences. 

https://doi.org/10.1016/j.matt.2023.08.023