A technical revolution in basic building materials could soon lead to major changes in the face of modern construction. Jon Herbert looks at a range of developments.
Innovation is catching up with construction. Robotic brick-layers, automation and prefabricated factory house-building promise early technical answers to a severe skills shortage and also mark the end of traditional wet trades. Drones are now central to survey health and safety. Put together, the changes are beginning to replace the need for many human workers on site.
However, a revolution in materials is expected to have an equally important impact.
The use of some basic materials has changed only marginally in the past. Steel replaced iron. Concrete often replaces stone. Timber is enjoying a new popularity. Modern strong, lightweight, easy-to-use resins, polymers, composites, plastics and alloys have also become indispensable.
However, a new generation of smart developments with entirely different properties is waiting in the pipeline. References to 2D materials and 4D printing hint at what is to come.
The future will almost certainly see self-repairing materials, plus those designed to self-assemble, or with programmable assembly capabilities that can work without human hands in difficult places at increasingly reasonable costs.
Less is more
One smart way to use materials is to cut their use in terms of raw commodities, human input, time and energy. Materials of the future are being developed to do this in radical ways.
One approach is to embed processors within new materials so that a specific change can be triggered by the addition of a stimulant such as water or temperature variations.
Construction by and large is not on this curve. Aerospace leaders, such as Boeing and sports equipment manufacturers like Adidas, are. Developments are expected to bear fruit well into the future. But an early start is said to be important.
Just add water
Inveterate walkers and climbers may be used to feeling on arrival at a cold, dark, soaking wet campsite how wonderful it would be to have a tablet that, placed on the ground, could transform itself instantly into a fully-pitched tent — complete with stove and boiling water.
That reality is still some way off! But it illustrates the concept behind the development of some modern materials.
One approach is the creation of materials that either assemble themselves or, through the use of 4D printing (time is the fourth dimension) create materials that are pre-programmed to behave in certain predetermined ways.
Research at the Massachusetts Institute of Technology (MIT) in Boston has gone down the route of developing pre-programmed shoes. The secret is in being able to print a detailed pattern into a stretched fabric that, with no other input, folds itself into a fully-formed shoe once released.
Technology is also taking another route which might be more applicable to construction, building and civil engineering. Programmable materials are being developed that transform into something else once a stimulus is added.
Examples include wood and timber waste, plastics or metal printed with embedded patterns. When an energy stimulus is applied, which could be moisture in the case of wood, or a temperature change for metals, the printed material responds by metamorphosing into a predictable shape.
This could be significant for construction. While self-assembling materials seem to be better suited for manufacturing where the need is for accurate replication again and again, innovative technologies could have important applications at, for example, enclosed urban sites difficult for plant and people to reach.
No need to read the instructions
An exciting application could be through the use of components that locate each other and assemble themselves into remote structures with no direct intervention by people or external technology.
However, more progress has been made in programmable “smart” materials that do not necessarily have to be electrically or mechanically-based. Instead, the smartness can come from the materials themselves, potentially saving a lot of cost and physical assembly time. Rather than depending on external sensors to detect conditions and trigger a reaction, the programmable material itself is a sensor.
What does this mean? A basic example is wood. Add moisture and wood swells up and transforms itself naturally. The aim is to take these kinds of properties further in a stable way.
This can be done by printing on, bonding with, or weaving the required additional information into materials to produce a specific finish, size, shape or composition when the correct stimulus is applied.
An obvious advantage and application is the potential for self-repairing materials that self-activate, expand, retract or adjust when particular conditions dictate.
Major advances on a minute scale
Graphene is a British development that could have a major future in construction. However, as with other ultra-innovative materials, a couple of decades may be needed for its full potential and best practice applications to be brought to the marketplace effectively.
A child of Manchester research, the priority for its developers is to shorten that concept-to-implementation period as much as possible.
Graphene is essentially a one-atom-thick layer of layer of graphite atoms with incredible properties — a 2D material. The resulting honeycomb lattice is the thinnest material ever discovered that is surprisingly 200 times stronger than steel.
Extremely light, very tough but permeable to water, graphene is nevertheless a barrier to some of the simplest gases. It is also in very short supply at the moment.
The National Graphene Institute in Manchester is due to be joined by the Graphene Engineering Innovation Centre in 2018 with the aim of moving a wide range of 2D materials from research to commercialisation as swiftly as possible.
A priority will be to work with small and medium-sized enterprise (SMEs) in addition to an input of public money.
Although the construction industry is not particularly amenable to investing in new materials, a substance as strong as graphene could be of immense benefit to infrastructure building.
However, an early introduction is more likely to come as an addition to other products such as polymers, resins, steel or concrete. But developments here are at an early feasibility stage.
An obvious bottleneck is the ability to manufacture materials cost and time efficiently on an adequate scale; current weekly production rates of 500g are set against a projected global demand of some 54,000t by 2025.
The current cost of graphene production is circa £400 per gramme. Much work remains to be done there.
The other breakthrough technology that is already at work in construction is large-scale 3D printing. Dubai was the site of a world first in 2016 with the printing of an office building with a floor space of 250m2. Modules were printed in 17 days and put together in two more.
Strength and maintenance requirements are said to be negligible when compared to conventional buildings.
Behind the curve
Disruptive technology of this kind could be very useful but currently has no real drivers in construction, which is accused regularly of being conservative in preferring old and tried practices.
However, the problem is more complex. In many cases, legislation may have to be changed. There are health and safety precedents that much of the industry would be loathe to change for legal reasons. Nobody wants to be sued for high sums should problems occur many years into the future.
Having said which, other sectors such as biomed, automation and aviation are making strides forward with innovations that respond to changing parameters such as pressure and rising or falling temperatures.
Competitive cultures are one reason for differentiating products in industries that are otherwise much the same. In contrast, construction and building programmes tend to be very individualistic.
A more optimistic view is that innovation in one sector will eventually cascade into others. Early innovation risks are avoided. However, there is a risk of being left behind the commercial curve.