Use of Biological Additives in Concrete Pavements: A Review of Opportunities and Challenges

Abstract

In light of the substantial life-cycle energy footprints and environmental impacts of traditional pavements, the use of biological additives in pavements is becoming an appealing option that helps the greening of pavements. For instance, by utilizing native microorganisms to produce healing product(s) and strengthen the deficient region(s), bioconcrete enables the autonomous self-healing of concrete pavements. Healing mechanisms, delivery methods, and types of bacteria are the main factors that define healing performance. Based on the metabolic pathways similar to bioconcrete, biocement uses soil from the local site and a mixture of nutrients and bacteria to form biocementation. Production process, feasibility, benefits, and concerns are currently the main research subjects of biocement. Compared with synthetic topical sealers, biological surface sealers provide a more effective and safer way to combat material deterioration of concrete pavements. Currently, these biological pavement solutions are not yet widely used in modern pavement design or construction because of the lack of understanding of their long-term effects and performance. The relatively higher investment of implementing them in pavements is another challenge. However, their advantages are self-evident, including the benefits in strengthening the mechanical properties and autonomously healing the cracks of concrete and other construction materials, the friendliness to the environment, and the potential of reducing the life-cycle cost of concrete pavements. Continued multidisciplinary exploration in this genuinely innovative field is anticipated to help overcome technical and nontechnical barriers and unlock the potential of biological additives for their use in concrete pavements.