Small Pores, Big Impact-Controlling the Porosity Allows for Developing More Sustainable Construction Materials

Owing to the ongoing increase in world population, two challenges in the field of construction materials need to be solved: first, the sustainability and, second, the durability of the materials used. Whereas there are first concepts to address either issue independently, combined approaches are still scarce. We here present a hybrid mortar system, in which two different additives achieve this dual goal: a biological additive minimizes the ingress of water into mortar, thus improving the durability of the material, and a second group of additives reduces the ecological impact of the material by lowering the amount of carbon dioxide emission associated with cement production. Our results indicate how either additive affects the pore structure of the hybrid material and how this affects its mechanical competence and resistance to water ingress. If a similar concept can also be applied to other cementitious materials, it may present an urgently needed short-term solution to improve the sustainability of construction materials.