Concrete is a ubiquitous building material and is often cited as the most consumed product on Earth, second only to drinking water.1
As this legacy concrete infrastructure continues to age, the maintenance and repair of concrete is of increasing strategic importance to defense and civilian infrastructure. Missile silos and naval piers, for example, are often decades old and not easily replaced, and the DoD relies on concrete airfield pavements that are prone to damage from overuse. or attacks and require rapid repairs to maintain high operational rates.2
Concrete cracking and corrosive deterioration contribute most to the degradation and loss of serviceability of steel reinforced structures,3 but current technology is limited to surface treatments which are short lived and do not address the underlying causes of decomposition. New research, however, suggests that interdisciplinary technologies can be used to give weathered concrete self-healing capabilities.
DARPA recently launched the Bio-Inspired Restoration of Aged Concrete Buildings, or BRACE. BRACE’s goal is to develop technologies that impart a sustainable self-healing capacity to concrete at depths that treat cracks early, to repair them, prevent their spread and extend the functionality of critical infrastructure.
Inspired by the vascular systems that support ongoing repair in multicellular organisms and ecosystems, BRACE will develop approaches to integrate healing “vascularization” for sustained damage repair and prevention.
The 4.5-year research effort will include two Technical Areas (TAs) focused on developing sustainable systems for transporting healing substances in concrete, as well as practical tools to apply, maintain and predict function and performance long term of these. systems.
TA1 will meet the challenges of engineering bio-inspired approaches to establish long-acting vascular structures deep in concrete both to repair cracks and to provide self-diagnostic signals that allow the user to know that they still work after years or decades.
In TA2, artists will develop methods for applying and maintaining TA1 systems in concrete, rapid aging test rigs for vascularized concrete, and models that predict system effectiveness to avoid the need for future repairs. Performers will respond to both TAs, and BRACE will refine these capabilities in two paths aligned with long-term (e.g., steel-reinforced marine or buried infrastructure) and rapid (e.g., expeditionary airfield runway repairs) repairs ).
Although the program targets these use cases, the technologies developed in BRACE could eventually be adapted for civilian infrastructure.
BRACE implementers will engage with U.S. government and DoD stakeholders, as well as appropriate regulatory authorities. Safety is paramount and all research will be subject to regular review by independent laboratory and regulatory bodies to ensure BRACE technologies do not pose a threat to human or structural health. In addition, teams are also required to collaborate with experts in ethical, legal and societal implications (ELSI) and ensure that the research addresses all related concerns.
A Virtual Nominator Day for potential Nominators is scheduled for April 13, 2022.
For more information and how to register, go to: https://sam.gov/opp/fea8b749efde4076b4b6c75453991673/view.
An Agency Wide Announcement (BAA) solicitation should be available on SAM.gov in the coming weeks.
- Colin R. Gagg. “Cement and Concrete as an Engineering Material: A Historical Appraisal and Case Study Analysis.” Analysis of technical failures, May 2014. https://www.sciencedirect.com/science/article/abs/pii/S1350630714000387#:~:text=Abstract,all%20other%20building%20materials%20combined.
- Haley P. Bell, Benjamin C. Cox, Lulu Edwards, Lyan I. Garcia, Nolan R. Hoffman, Mariely Mejías-Santiago, and Jared L. Johnson Rapid Airfield Damage Recovery Technology Integration Experiment. US Army Corps of Engineers Engineering Research and Development Center. 2019.
- Taffesea, WZ and E. Sistonen, Life prediction of repaired structures using the concrete recasting method: state of the art. Procedia Engineering, 2013. 57: p. 1138-1144.