subways

Green grout for stabilizing buildings

March 31, 2025 By EarthWise Leave a Comment

We are all familiar with the grout that is used for tiles in our homes. We are less familiar with grout that is used to stabilize the soil beneath buildings. Grouting is a process of ground improvement by injecting materials that can fill voids and cracks, strengthen and increase the bearing capacity of soil, and reduce permeability.

Traditional grouting methods have environmental downsides. Most often, silica-based chemical grouts are used, and they are produced through energy-intensive processes that contribute substantially to carbon dioxide emissions. As is the case for all materials and practices of the construction industry, developing sustainable, low-emission alternatives to conventional grouting materials has become an important priority.

Researchers from the Shibaura Institute of Technology in Japan have developed an innovative new grout material called Colloidal Silica Recovered from Geothermal Fluids. This grout material enhances soil stabilization and simultaneously reduces the environmental impact of geothermal energy harvesting.

Geothermal energy production generates large amounts of silica-rich waste fluids which creates challenges for its maintenance and disposal. The new grout repurposes this waste material thereby transforming an industrial byproduct into a valuable construction material.

The new grout material is particularly valuable in earthquake-prone regions, where soil stabilization is essential in preventing structural damage during seismic events. In addition, the grout’s superior water-sealing properties makes it ideal for underground construction projects like tunnels, subways, and basements. The new grout in an important step for the construction industry’s efforts to achieve carbon neutrality.

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From Waste to Wonder: Revolutionary Green Grout for Sustainable Construction Practices

Photo, posted July 8, 2011, courtesy of MTA Construction & Development Mega Projects via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Low Fares Clean German Air | Earth Wise

September 29, 2022 By EarthWise Leave a Comment

Germany’s parliament set summer public transport fares at 9 euros a month as a way to slash pollution and reduce imports of Russian oil. The low price included all buses, trams, subways, and regional trains, effectively lowering prices by more than 90% in some cities. Berliners saved 98 euros on their monthly travel pass; commuters in Hamburg saved even more.

The program began June 1 and ended August 31. The bargain rates drove widespread use of public transport and discouraged the use of cars, which already was undesirable due to high gasoline prices. Over the three-month period, transit authorities sold over 50 million subsidized tickets. One out of five travelers were using public transport for the first time, according to surveys.

According to an estimate from the Association of German Transport Companies, the program helped to avoid 1.8 million tons of carbon dioxide emissions. This is roughly equivalent to taking 1.5 million cars off the road for the summer or planting 30 million trees.

The discount transit program had a clearly positive effect on the climate and, obviously, was a source of financial relief for German citizens. Last year, Germany was the largest buyer of Russian oil in Europe and it wanted to make drastic reductions in its purchases. The success of the program prompted many to ask for it to be continued. However, the program cost the government about 2.5 billion euros in reimbursements to transit companies. The German government has said it would not be extended.

Nonetheless, German policymakers are weighing other proposals for low-cost public transit. Clearly encouraging people to use public transit pays dividends.

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Germany’s Cheap Summer Train Fares Prevented 1.8 Million Tons of Carbon Pollution

Photo, posted June 6, 2022, courtesy of 7C0 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Should New York Build A Storm Surge Barrier?

December 6, 2019 By EarthWise Leave a Comment

In 2012, Superstorm Sandy’s storm surge combined with a high tide and buried lower Manhattan under 13 feet of water. Across all five boroughs, subways, highways, and parking garages flooded and homes and businesses were destroyed. Sandy caused nearly $20 billion in damages in New York City alone and more than 50 people died.

Ever since that disaster took place, there have been discussions about building storm surge barriers to protect the city from future storms. Columbia University’s Sabin Center recently hosted an event to discuss the feasibility of building such barriers.

A study by the U.S. Army Corps of Engineers called the NY and NJ Harbor and Tributaries Focus Area Feasibility Study (HATS, for short) evaluates five options for coastal protection, which range in scope and price.

The most extensive option would involve constructing six miles of storm surge gates along with 26 miles of floodwalls, levees, and buried seawalls. This option would cost $62 billion but could theoretically save $131 billion in damages and protect 95% of the study area.

The study also considers the side effects of building storm surge barriers. These include environmental impacts such as effects on fish and wildlife, water quality, noise and vibrations, and changes in water flow. While these effects can be quite serious and there is opposition from many quarters related to environmental impacts, others point out that there is really no other credible defense against storm surge. The debate over whether or not to build storm surge barriers could easily last for many more years.

In the bigger picture, storm surge barriers do nothing to protect against rain-driven flooding, sea level rise, and tidal floods which continue to increase.

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Should New York Build a Storm Surge Barrier?

Photo, posted October 30, 2012, courtesy of Pamela Andrade via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.