Image Source: Wikimedia Commons (public domain)
The world is fast approaching its limit. As we continue to pollute, the Intergovernmental Panel on Climate Change’s carbon budget estimates we must stay below 2.9 trillion tons of carbon dioxide emissions in order to keep global temperatures from rising 2℃ by 2050. According to the National Climate Assessment, rising global temperatures from climate change contribute to escalating storms and floods, as well as extreme weather events such as hurricanes. Already, we’re at about 80 percent capacity in terms of the carbon budget. The Earth is warmer than it was before industrialization began.
From the looks of it, global warming will continue as people migrate to cities. Nearly 70 percent of the world’s population will live in cities by the year 2050, and right now cities pump out 70 percent of greenhouse gas emissions. Buildings alone contribute nearly 40 percent of emissions. To limit emissions, the future of city architecture must be green.
Green buildings make a big difference. So far, green buildings cut down on emissions in the United States by an estimated 34 percent. This is just the beginning. Architects and city planners around the world are looking towards sustainably sourced materials and LEED certification for green buildings. LEED is the standard for green buildings, and with LEED v4, the standard is higher than ever. Through a credit and points system, LEED incentivizes architects and other decision-makers to maximize building sustainability using credits. Thanks in part to this system, green buildings are going to get even greener.
LEED v4 treats buildings like living, breathing entities. The more fit the body, the more integrated it is with the environment. This call to optimum sustainability includes every decision-maker. LEED encourages planners to put buildings in sites where they can take advantage of shade, existing utilities, and thoroughfares for walking and biking. LEED encourages project teams to analyze detailed information from manufacturers about the sourcing of materials. Meanwhile, solar panels help green buildings put energy back into the grid, and rooftop plants help reduce rainwater runoff. Furthermore, concrete plays a role in keeping green buildings green.
How Concrete Plays a Role
Over time, escalating storms and floods weaken and degrade a key part of city and building infrastructure: concrete. You can build a building green, but if the foundation doesn’t have waterproof concrete, it can develop leaks, which lead to costly repairs. The same goes for walls and other parts of a green structure. The more repairs green buildings need, the more energy is consumed.
Concrete is notoriously susceptible to water damage. That’s why concrete waterproofing—particularly bentonite waterproofing—is essential. Bentonite waterproofing keeps the deluge of rainwater and flood-water from degrading the concrete at the base of our buildings, waterways, and streets. Bentonite waterproofing keeps flood water and waste water from seeping through concrete and polluting the water table beneath buildings. Furthermore, concrete with bentonite waterproofing can help catch rainwater and channel it to where it can be reused.
Additionally, when water permeates concrete building foundations, it creates an issue with water vapor. Vapor, the invisible destroyer, rises up into buildings and causes mold, mildew, and fungus. Long after floods or storms soak structures, building owners who haven’t applied concrete vapor barriers find themselves stuck with extensive repairs that cost thousands to millions of dollars. Concrete vapor barriers can help builders get LEED credits for optimizing indoor air quality.
Right-sized Buildings and Sustainable Concrete
LEED also incentivizes architects to collaborate with structural engineers on “right-sizing” the building’s structure—that is, making sure the building’s size and proportions contribute to efficient energy consumption. One great example of this is R.Torso.C.
R.Torso.C is a micro-home in Tokyo designed by award-winning architect Yasuhiro Yamashita. At just under 338 square feet, the house employs advanced design techniques to make it seem bigger than it is. One such technique is “NU-KE (noo-kay),” the “multi-layering of walls and spatial volumes” to emphasize views of the sky, creating the feeling of open space.
The design team’s primary innovation with R.Torso.C is its use of a new type of concrete, the idea for which dates all the way back to ancient Rome. The concrete, called shirasu, uses volcanic ash instead of sand. “This technique was used in ancient Rome and served the Pantheon for 2,000 years. And before this project, we were just disposing of the volcanic ash that we have here in Japan,” the architect told Architectural Digest.
Shirasu takes advantage of a pozzolanic reaction that causes the concrete to harden over time. When a substance rich in silica with no cementing properties—in this case, volcanic ash— combines with calcium hydroxide and water, the chemical reaction creates a concrete that continually strengthens in the long term. In other words, water doesn’t degrade shirasu, it makes it stronger.
While bentonite waterproofing and vapor barriers are necessary for existing concrete that will break down with the invasion of moisture, R.Torso.C is a building made of a type of concrete that very well may be the future of sustainable concrete. R.Torso.C is right-sized, small enough to make room for many more houses like it, paving the way for the megacities that will exist when 70 percent of the world’s population is living in cities in 2050.