The world consumes billions of water bottles — every year. Of those, only 1 of 5 is recycled. Fortunately, a handful of MIT students have developed a solution to this problem, and it involves repurposing waste plastic bottles to reinforce concrete. Because the newly-invented method results in the concrete being more durable than existing concrete, plastic bottles may soon be used to construct everything from stronger building foundations to sidewalks and street barriers, reported The MIT News. According to the study, which was published in the journal Waste Management, MIT students discovered a method to produce concrete that is up to 20 percent stronger than conventional concrete. First, plastic flakes are exposed to small amounts of harmless gamma radiation. Then, they are pulverized into a fine powder, after which it is added to concrete. The discovery has far-reaching implications, as concrete is the second most widely used material on Earth (the first is water). MIT News reports that approximately 4.5 percent of the world’s human-induced carbon emissions are generated by manufacturing concrete. By replacing small portions of concrete with recycled plastic, the cement industry’s toll on the environment would be reduced. The newly-discovered method would also prevent millions of water and soda bottles from ending up in landfills. Michael Short, an assistant professor in MIT’s Department of Nuclear Science and Engineering, said, “There is a huge amount of plastic that is landfilled every year. Our technology takes plastic out of the landfill, locks it up in concrete, and also uses less cement to make the concrete, which makes fewer carbon dioxide emissions. This has the potential to pull plastic landfill waste out of the landfill and into buildings, where it could actually help to make them stronger.”

Some 2,000 years after they were first erected, Ancient Roman harbors made from concrete are still standing across Europe. Meanwhile, more modern constructions have proved far less durable. Finally, scientists have solved the puzzle of what made the ancient concrete so strong — and they think the discovery could make modern buildings more environmentally friendly. The results are published in American Mineralogist. Concrete used for ancient sea walls was made by mixing lime, seawater, volcanic ash and rock. Researchers have now discovered that elements in the ash react with sea water, which actually strengthens the material. Researchers discovered the Roman concrete contained aluminium tobermorite, a rare mineral that adds extra strength. When the Roman concrete was exposed to seawater, the tobermorite crystallised and spread. The researchers said that long-term exposure to sea water helped these crystals to continue growing, reinforcing the concrete and preventing cracks from developing.

As anyone who's ever visited Italy knows, the ancient Romans were master engineers. Their roads, aqueducts, and temples are still holding up remarkably well despite coming under siege over the centuries by waves of sacking marauders, mobs of tourists, and the occasional earthquake. But it seems the Romans also knew a thing or two about making concrete. While world's 1960s concrete tower blocks and flyovers are crumbling, Roman monuments such as the Pantheon and the Coliseum are still standing. Now scientists have discovered the secret ingredient behind the longevity of Roman concrete - volcanic ash. The study by the University of California, in Berkeley, found Roman concrete showed no corrosion, with a smooth surface suggesting long-term stability. Manufacturing modern cement requires heating a mix of limestone and clay at 1,450C. But Roman architectural mortar uses 85 per cent volcanic ash, fresh water and lime, which is cast at a much lower temperature, significantly reducing its carbon footprint. Now the researchers want to take the Roman techniques and apply them to modern cements. Dr Marie Jackson said: 'If we can find ways to incorporate a substantial component of volcanic rock in the production of specialty concretes, we could greatly reduce the carbon emissions associated with their production. We could also improve their durability and mechanical resistance over time.'

Construction workers in downtown Los Angeles finished laying the foundation for a planned 73-story skyscraper expected to be the tallest west of the Mississippi River as they completed the world's largest continuous pour of concrete, reported news agency Reuters. The 21,200 cubic yards of concrete weighing some 38,200 metric tons was hauled to the site by a fleet of over 200 trucks making a total of 2,120 trips in a continuous 19-hour. The foundation is expected to take two weeks to completely harden, during which cool water will be pumped through a network of tubes embedded in the massive slab to absorb heat as the concrete cures. The New Wilshire Grand tower, designed to include 900 luxury hotel rooms, 37,200 square meters of offices, plus retail space, is slated to be completed in late 2016 and open in early 2017. The US$ 1 billion project is being developed by Korean Airlines, which also owned the old Wilshire Grand building that was demolished to make room for the new tower. The marathon effort to lay its foundation was certified by the Guinness World Records as the largest continuous pour of concrete ever by volume, surpassing by just 200 cubic yards the previous record set at the Venetian hotel and casino in Las Vegas, according to Michael Empric, the Guinness adjudicator. The Venetian was completed in 1999. Rising 73 stories into the Los Angeles skyline, the New Grand Wilshire tower will measure 335 meters high, including a spire affixed to the top of the building, in a design that developers boast will make it the tallest building west of the Mississippi.