When most people think of building materials, one of the first to come to mind is concrete. The mixture of water, cement, and aggregates has been used worldwide for thousands of years and continues to be an integral part of construction years after the Egyptians used it as a building material to create concrete columns, many of which still exist 3,600 years after they were made.
Concrete is a popular building material. Unlike building materials such as bricks, wood or steel, concrete arrives on a building site in a ‘plastic’ state and can be moulded, coloured, and shaped to create everything from a simple home staircase to docks, silos, bridges, and epic structures like the Hoover Dam, which contains 4.5 million cubic yards of concrete.
Since British stone mason Joseph Aspdin mixed finely ground limestone and clay with water and created Portland cement back in 1824, concrete technology has changed in not only strength but sustainability. From pre-fabricated products to the latest environmentally aware ‘green’ materials, building products have become more durable than ever before.
One of the most remarkable recent innovations is self-healing concrete, which is inspired by the human body’s ability to repair itself. A group of Dutch scientists at the Delft University of Technology in The Netherlands embedded concrete with limestone-producing bacteria and calcium lactate.
Much like breaking a bone sees osteoblast cells act to produce minerals and create new bone, cracks in concrete signal Sporosarcina pasteurii or Bacillus pseudofirmus bacteria into action, consuming the calcium lactate, and converting it to calcite, repairing the crack. Costs remain high, but this remarkable innovation is estimated to be able to heal itself for two hundred years.
Another recent initiative is sustainable concrete. Since concrete manufacture is responsible for an estimated seven to ten percent of carbon dioxide emissions worldwide, concrete’s environmental footprint is being reduced through the inclusion of recycled materials, including glass and even slag. Waste products that would otherwise need to be hauled away for disposal are being given a new life as part of concrete structures.
As clients demand more environmentally friendly initiatives and reduced carbon emissions, construction companies will see a greater acceptance of using local, recyclable materials in concrete mixes.
Nations such as Australia have already embraced modular construction methods. These structures can take a number of forms and be made from varied materials including wood or pre-made concrete sections.
Modular construction is used to create walls, floors, and other structural elements and sees precast concrete sections manufactured in moulds or forms, transported to sites, and erected.
In some instances, buildings are made directly on site through ‘tilt-up’ construction, where forms are made on the ground, concrete is poured and set, and entire sections are then lifted into place to create walls, columns, and supports.
The method was initially used to create homes over one hundred years ago, today’s tilt-up concrete slabs take the form of hotels, school sand, office buildings, even massive warehouses. While cast sections must be precisely made on level ground and require bondbreaker chemicals, the technology offers many advantages, not the least of which is the ability to create sections of exacting thicknesses poured on site.
Both modular and tilt-up construction hold many advantages over other forms of building, from the speed of assembly and lowered environmental impact – since no waste material is generated – to concrete’s ability to withstand the elements, insects, and vermin.
Thanks to ongoing research, emerging technologies and advanced manufacturing techniques are becoming more long-lasting, innovative, and environmentally friendly. This includes such materials as highly efficient ‘thermal bridging’ insulation, which has an estimated increased R-value that is forty percent higher than traditional insulation as well as other passive means to keep buildings cool in summer and warm in winter.
One of the most exciting advances in the construction industry is undoubtedly the ability to harness energy from sources other than electrical grids. Building-integrated photovoltaics, or BIPV, are being used both in new buildings and retrofit projects.
BIPV is being used as a means of structures powering themselves by generating electricity through the use of transparent photovoltaic glass, essentially solar panels, which comprise the envelope, including windows, roofs, and other areas.
Building integrated photovoltaic (BIPV) glazing can help buildings generate their own electricity, by turning the whole building envelope into a solar panel. Companies such as Polysolar provide transparent photovoltaic glass as a structural building material that can be used to form windows, facades, and roofs. Polysolar’s technology is efficient at producing energy even on north-facing, vertical walls, and its high performance at raised temperatures means it can be double glazed or insulated directly.
As well as saving on energy bills and earning feed-in tariff revenues, its cost is only marginally higher than traditional glass, since construction and framework costs are the same while cladding and shading system costs are replaced.
Traditional solar panels surfaces must be directed towards the sun. However, BIPV can be used on walls to gather non-directional low-light. Polysolar Ltd. Was established in 2007 in the United Kingdom and is leading the way in innovating and manufacturing thin-film photovoltaic energy solutions which have already been used in gas stations and a solar bus shelter in London’s famous Canary Wharf.
Another unique energy-generating environmentally sustainable technology comes from UK company Pavegen, which was founded in 2009. Every day around the world, billions of footsteps are made by pedestrians, so why not harness the kinetic energy created by this physical motion? Pavegen had a vision “to redefine sustainability in the built environment, with the creation of a pioneering flooring technology that generates electricity from footsteps and captures data,” according to the company.
Pavegen technology harnesses energy generated as people walk on customizable flooring systems that can be used both indoors and outdoors. Once weight is placed on Pavegen tiles, electric-magnetic induction generators use an induction process and a rotary motion to generate off-grid electricity.
All tiles are fitted with a wireless device that transmits movement data analytics in real time and directs power to where it is needed most. The technology is best suited to high foot traffic areas and connects to building management systems and mobile devices. It has been used to power floodlights around a football pitch in Rio de Janeiro, Brazil and street lights outside Canary Wharf in London, England.
In late 2016, Tesla – well-known for unique energy-efficient products such as cars and the Powerwall home generation system – announced rooftop solar tiles. These tiles capture sunlight and either transform it into energy for immediate use or store it in a Powerwall battery.
After Tesla Motors shareholders had approved plans to acquire solar energy business SolarCity, Tesla Chief Executive Officer Elon Musk stated that his company’s new solar roofs will “actually cost less than [a] normal roof before you even take the value of electricity into account.” This estimate includes installation costs and does not require subsidies.
If this goal comes to fruition, it would not only result in homeowners having much more control over their electrical destiny – as their reliance on the grid would be lessened or eliminated entirely – but greatly reducing their carbon footprint, since solar produces zero carbon emissions. Additionally, these systems, once installed, are likely to boost the property value of a home.
In coming years, the construction industry will continue to use tried and true materials such as concrete, wood, and steel. However, as environmental awareness increases, these will be joined by newer, longer-lasting, and sustainable products and technologies.