This talk is a sharing of a chapter in the recent book entitled “Biochar for Environmental Management - Science, Technology and Implementation” [1]. Focusing on the application of biochar in buildings and roads, it is more than just a review of the state-of-the-art in this aspect of biochar but aims to develop the fundamental principles and frameworks to understanding why and how biochar has the observed effect on concrete and asphalt. 

This talk is divided into two segments. In the first, the overall principles on how biochar results in positive effects on concrete or asphalt is illustrated - in essence, this can be attributed to biochar's influence on the hygro-mechanical properties of these construction materials by modifying their microstructure as a result of changing the moisture distribution in them. 

In the second segment, attention will be focused on the applications of biochar in concrete and asphalt. Specifically, the ways in which the filler effect, particle size, particle shape, macro- and micro-porosity, permeability, and the “reservoir effect” afforded by biochar modifies the moisture distribution in the concrete and asphalt media will be discussed. With this understanding as a background, a number of case studies on biochar concrete and asphalt research around the world will be shared. 

Finally, a few key areas of future development will be discussed - including the use of biochar to augment carbon mineralization in curing green concrete, such as limestone calcined clay concrete.