Lightweight building materials offer a whole list of benefits. From cost savings to improved fire safety and sustainability, these innovative materials are proving their worth on construction sites.
However, it’s important to note that these materials don’t just reduce material weight, they also have better ductility and thermal properties.
Metal Alloys
Alloys are a mix of different metals that take advantage of certain properties of each. They are often stronger, harder or more resilient than pure metals. For example, tin and copper create the alloy brass, which is used in everything from pencil sharpeners to ship parts. When tin and copper are mixed together, their different atom sizes prevent the layers from sliding over each other as easily, so they stick to each other more firmly, like contrasting hooks and loops on velcro. This makes the alloy much harder and stronger than either tin or copper.
Another reason why metal alloys are better than pure metals is that they can be tailored to specific applications. For example, tin can be made softer and easier to cut by adding nickel, which also gives the material its color. Nickel is also a good choice to reduce corrosion and to make the alloy resistant to heat.
More recently, engineers are using new metal alloys to build lighter car and airplane components that can meet tougher fuel efficiency and emissions standards. The strength and durability of these metal alloys is helping cars, trucks and planes shed hundreds of pounds while preserving their structural integrity. These advanced alloys include high-strength steels, such as AHSS and aluminum blends. They are also attracting designers of consumer electronics, oil & gas equipment and other industrial machinery that requires lightweight materials.
Fiber-Reinforced Polymers (FRPs)
FRP composites consist of a polymer matrix embedded with fibre filaments to produce a strong and stiff material. The matrix consists of thermoset resins such as polyester, vinylester or epoxy and the fibres could be glass, carbon or aramid. The resins bind the fibres together to form the composite. The tensile strength of the FRP depends on the amount and type of fibres, their volume and how they are positioned within the matrix.
Due to their high tensile strength and lightweight nature, FRP is an ideal alternative to steel reinforcement bars in concrete structures. In addition, FRP can increase the load-bearing capacity of existing structures resulting in higher safety margins. This enables structures to be reused for decades without requiring extensive rebuilding work.
The application of FRP to concrete infrastructures as internal reinforcement has been actively investigated in many research laboratories and professional organizations worldwide. It is a non-intrusive solution that increases the load-bearing capacity of concrete structures and can bring them up to their design capacity.
However, a number of critical issues have to be taken into account, including the loss of significant flexural and shear strength with the use of FRP reinforcement. This can cause premature tendon rupture. The risk of this can be minimised by using the appropriate reduction factor based on the ACI code (e.g. for GFRP: 0.8, for basalt: 0.6) and using an adequate corrosion protection.
Transparent Aluminium
Aluminium is one of the most popular and versatile construction materials in modern times, but a transparent form of it hasn’t been widely available until recently. Researchers have developed aluminium oxynitride, or ALON, to be see-through and super tough at the same time. It is four times harder than fused silica glass and 85% harder than sapphire, but it is also incredibly light-weight and able to resist damage from radiation and oxidation.
This material is being used in military applications because of its bulletproof qualities. It has been discovered that a laminated pain of aluminium oxynitride can stop a powerful 50 calibre bullet – something that traditional bulletproof windows made from polycarbonate or glass cannot do. In addition, it is highly resistant to heat and can transmit infrared waves without absorbing them.
This see-through and hard material is not new, but the process for making it has been accelerated by the recent discovery of how to make solid aluminium invisible. It was done by applying a high-powered X-ray source to the material for a brief period, which turned it from opaque to translucent. This is an exciting development that could lead to a lot of future possibilities. The researchers hope that this method of turning solid aluminium into an exotic state of matter will be useful in areas like planetary science, astrophysics and nuclear fusion research.
Lightweight Insulation Materials
Lightweight insulation materials are vital in construction because they help to keep buildings warm and cool. Engineers are looking for innovative and sustainable ways to build with these lightweight materials. Engineers at the Karlsruhe Institute of Technology, for instance, are experimenting with microstructured construction materials that are inspired by bones and bees’ honeycombs. These structures have a density that is lower than water, but they are more stable than massive materials such as aluminum and steel.
These lightweight insulators can be made from minerals, plant fibers and even waste from durian or coconut. They are also less polluting than traditional building materials. Some of them are available as boards or in the form of structural insulated panels, which are easy to handle and cut for installation. They can be treated with borate to resist pests and mold.
Other insulating materials include mineral wool (often called rock or earth wool) and plastic foams like expanded polystyrene, phenolic foam and extruded polyisocyanurate. These products are typically produced in blocks that professionals can easily cut to form insulating boards for walls and roofs.
Another insulation material that is becoming increasingly popular is a specialist type of vacuum insulation. These materials are filled with tiny particles of a heat-absorbing material, such as silica or graphite. Because the particles can only interact with each other at certain points, they have extremely low thermal conductivity and impede convection and radiation.