DARPA is looking for a "biological" way to restore concrete

The BRACE program logo shows the concrete restoration sequence

The American Advanced Development Agency (DARPA) has taken up issues of restoring and maintaining the infrastructure. Since last year, work has been underway on the BRACE program, during which they plan to find fundamentally new ways to restore and repair concrete and reinforced concrete structures. We consider "biological" technologies that can solve the problem without the need to dismantle structures or replace its elements.

The problem of degradation

Concrete and reinforced concrete are among the main modern building materials and are widely used in the construction of military and civilian infrastructure. However, for all their advantages, they can degrade with negative consequences.

Under the influence of external factors, as well as due to incorrect composition, non-compliance with construction technologies, etc. cracks appear in the concrete, and then it begins to crumble. External moisture leads to corrosion of metal elements, which reduces the strength of the structure, and also creates additional internal stresses. The strength of the structure gradually decreases, up to its complete destruction.

According to the DARPA agency, by now the US armed forces are fully faced with the problem of degradation of concrete structures. A lot of objects for various purposes, built in the middle of the XNUMXth century, remain in operation. Due to age and external factors, their condition leaves much to be desired and requires attention.

While American military builders have to use "ordinary" concrete

Not all such facilities can or should be repaired or demolished and rebuilt. In this regard, it is proposed to develop new repair technologies that allow restoring the integrity of building materials and structures without significant external impact.

Inspired by nature

In March 2022, DARPA announced the launch of a new research program called Bio-inspired Restoration of Aged Concrete Edifices (“Biologically inspired restoration of old concrete structures”) or BRACE (sounds like “Brace” or “Brace”).

As part of the new program, it is planned to re-examine the processes of degradation and destruction of concrete and reinforced concrete under different conditions and for different times. Based on the information collected, they will try to create a new technology for repairing and / or maintaining the integrity of the structure.

As part of BRACE, DARPA offers an interesting concept for damage recovery. We need some means that can create a network of thin channels in the damaged area or in the thickness of concrete, similar to blood vessels or mycelium. Through this network, materials for repair should be delivered to the damaged area in an optimal way. Once in the right area, the particles of the material will be embedded in the existing structure and strengthen it.

In repair mode, the canal network will have to ensure that a large amount of building material is quickly delivered to the damaged area to fill the resulting voids. Prevention will consist in similarly filling small defects before they increase and begin to pose a threat. In addition, DARPA would like to use a network of channels for material diagnostics and damage signaling.

How exactly the channels will be created is to be determined by the organizations participating in the program. It is possible to use certain chemical, biological and other means. At the same time, the cross section and configuration of the network of "vessels" should not adversely affect the strength of the restored structure, which is already weakened.

The program is divided into two so-called. technical areas (Technical Areas) that have similar but different goals. The task of the first "area" TA1 is the actual creation of a new technology. As part of the TA2 direction, methods for using new tools will be developed, as well as test systems and models for verification. In the future, a new task will appear - it is necessary to develop a high-speed version of the technology. With its help, they plan to repair minor damage to buildings, airfields, etc.

The BRACE program started in March last year and has four and a half years to complete. This means that new technologies should appear before the end of FY 2026. The timing of the appearance of new materials in engineering and building structures cannot yet be named. In the indefinite future, the transfer of new developments to the civilian sphere is not ruled out, where they will also find wide application.

Researchers and performers

A year ago, DARPA launched the BRACE program, and also opened a call for applications from organizations wishing to participate in it. On March 23, 2023, the agency announced the completion of the preparatory part of the program and the selection of its participants.

Three American organizations will be engaged in the full development of new technologies. This is the Livermore National Laboratory. E. Lawrence, University of Colorado and Battel Memorial Institute. They presented their own ideas and developments on the "biological" restoration of concrete.

XNUMXD printing of a cement mortar building

Unfortunately, the details of preliminary projects from BRACE member organizations have not yet been announced. Official reports mention that they all meet the basic requirements of the customer and are based on the idea of ​​a network of channels within the material. In this case, the general concept can be implemented in different ways.

According to DARPA, all three participants in the program will work in both "technical areas". They will have to develop new technologies, as well as adapt them for practical use. A set of measures and means for testing will also be created by the participants.

Applications

The main phase of the BRACE program has just begun, and its results will have to wait for several more years. In addition, there are no guarantees yet that the research participants will cope with the tasks. However, the DARPA agency already indicates the possible areas of application of new technologies and the expected effect.

The Pentagon has at its disposal a mass of military infrastructure of various kinds, in the construction of which concrete and reinforced concrete were used. These are various buildings and structures, airfield runways, port berths and even silo launchers for strategic missiles. A significant proportion of these concrete/reinforced concrete structures were built in the distant past and are gradually deteriorating.

With the help of the developed tools, in the future they plan to repair damaged objects and their elements. In addition, their use at the construction stage is not excluded, which will prevent further degradation of structures. As a result, old facilities will be able to stay in operation longer, and newly built ones will initially have an increased resource. In both cases, there will be known savings.

It is also planned to create funds for quick repairs. With their help, they are going to deal with combat damage to airfields and various buildings. This application imposes special requirements on the means of repair, but provides obvious advantages.

In the future, BRACE technologies will be able to move into the civilian and dual-use areas. Concrete structures are used almost everywhere, incl. on objects of critical importance. The introduction of promising means of repair and prevention will allow relatively quickly and at minimal cost to restore damaged facilities and structures, as well as to prolong their operation. In addition, it will be possible to quickly repair with almost complete restoration of strength.

Obviously, new technologies from DARPA and contractors will definitely find their customers in the civilian sphere. Recently, the US has experienced serious infrastructure problems. For a number of reasons, the wear and tear of various objects in the field of transport, energy, industry, etc. does not receive due attention. Prevention is not carried out in full, which leads to various accidents. It is possible that the emergence and widespread use of BRACE technologies will reduce such risks, although it will not completely eliminate them.

Difficult tasks

Thus, the DARPA agency is launching full-scale studies as part of another promising dual-use program. The goal of the BRACE program is to create fundamentally new technologies in the field of materials science and construction. If the participants in the program do their job, then the US military and civilian construction workers will have new special opportunities.

However, the BRACE members face very difficult tasks. They will have to find tools with special functions and capabilities, as well as ensure their application in practice. Whether it will be possible to obtain all the desired results will become known in a few years. In the meantime, the Pentagon will have to carry out repairs in the usual way or demolish and rebuild facilities - with all the costs of time and money.

Comments

[Blue fox]

Thank you for the article. Really informative and interesting.
By the way, technologies of this kind were developed in the USSR, for example, restoration of damage to the runways of military airfields for heavy jet aircraft by filling funnels with polymeric fast-curing resins.
And one more thing, by the way, in the United States, military builders as such remained, unlike us. It is military builders, and not engineering troops, who have a completely different purpose, composition and equipment, or specialists of the military construction complex, that is, in essence, civil servants without shoulder straps performing the functions of a customer performing military construction work ... civilian contractors. Hence the losses among civilian builders, for example, during the construction of defense lines in the border regions with ukrooeykh. Do we need military builders in the modern Russian army? Is this a question? But we definitely need some formations of military personnel capable of carrying out construction work, primarily in such areas as road construction, bridge building (we remember the restoration of the bridge across the Dnieper after repeated attacks by Khaimars, when civilian repair teams died), the construction of airfields and long-term fortification facilities with their knowledge, specialized equipment, states with both air defense systems and UAVs, camouflage and other special ones. Well, it goes without saying that the servicemen should have the skills to conduct combined arms combat, and most importantly, be able and obliged to carry out work in the frontline zone by order. And let them be part of the engineering troops, it doesn’t matter.

[Mister X]

Previously, they knew how to build not only for centuries - for millennia!
Roman concrete is an example.
Ancient Roman plumbing, which is about 2000 years old.

[Rumata]

Quote: Mister X

ancient roman plumbing

"Weighty, rude, visible" (C)

[vovochkarzhevsky]

Liquid glass, it is also silicate glue and no biology is needed. Someone is making another loot.

[Knell wardenheart]

Conceptually, the idea with "bio-concrete" is quite interesting, I read about it in "Science and Life" not so long ago. There, the essence boils down to the fact that cultures of microorganisms are mixed into concrete, which are activated when exposed to oxygen - that is, in most cases with the appearance of cracks. Further, these microorganisms should redistribute (as conceived by the developers) calcium-containing substances mixed into the same concrete, absorbing and processing them, and actually cement the resulting cracks with their waste products.
Such a material will not be "eternal", of course, and, in principle, there are a lot of questions about how it is possible to implement this, as well as, in principle, about the inevitable increase in the porosity of the upper layers of such "bio-concrete" (and the question of the compatibility of the metabolism of these organisms with the presence metal structures, because in addition to oxygen, moisture will inevitably be required). But the thought is interesting.

As for "nano-capillary-permeated concrete" - empirically it doesn't seem like a good idea. Moisture will penetrate through such "pores" into the same iron frame (and on the entire scale of the structure), crystallization processes will occur there, with the change of seasons and under the influence of wind and temperature changes, due to thermal compression and expansion, such material will degrade faster ordinary concrete.

[Volunteer Marek]

Very interesting. This is really a big problem. And not only among the staff. Even the demolition of dilapidated reinforced concrete structures is still work! But I can imagine how much work and money it will cost to create these technologies! But, it will pay off handsomely.

[Rumata]

KIEV
The walls of St. Sophia Cathedral were laid out from large granite blocks, poured with "trout" - lime mortar with the addition of crushed bricks. Rows of large stones were finished with "plinth" - orange-pink wide and flat brick with a thickness of 2,5 to 4 centimeters. The outer masonry remained open, the facades of the building were not plastered.
LEGEND - kneaded on chicken eggs.

BYZANTIUM
An extract of ash leaves was added to the solution of the Sofia Cathedral.

[ximkim]

Cool
Civil engineering will be a stunning success.

[Colleague]

All discoveries will come down to adding eggs to the concrete, and the next patents of a typical concrete batch, so that no one has the right to build, except for "BLACK BLOCKS" ...