Nanostructured High-Strength LightWeight Concrete

Scientists from the Peter the Great Saint-Petersburg Polytechnic University (SPbPU) in Russia, have created several types of building blocks based on nanostructured high-strength lightweight concrete, reinforced with skew-angular composite coarse grids. The development has unique characteristics, enabling the increase of load-carrying capability by more than 200% and decrease in specific density of the construction by 80%. In addition, among the advantages, are resistance to corrosion, aggressive environments and excessive frost resistance.

Researchers calculated that the service life of the building structures, made with the use of this reinforcement system, will increase at least 2-3 times in comparison with its modern analogs.

Such system allows to ensure the structure integrity even in conditions of seismic activity, since the load is distributed throughout the structure as a whole, and not by individual reinforcement bars. The invention can be used in the construction of bridges and pedestrian crossings, non-metallic ships, low-rise residential buildings” says Alexander Rassokhin, graduate student at SPbPU. Andrey Ponomarev, Professor of the Institute of Civil Engineering is the co-inventor of the new  construction technology.

The fundamentals of the research have been described in an article “Hybrid wood-polymer composites in civil engineering” at the Magazine of Civil Engineering.

Source: https://www.eurekalert.org/

Wooden SkyScrapers

High-rise wooden buildings, such as 14-storey apartment building “The Tree” in Norway, are altering city skylines in what the timber industry is heralding as a new era that will dent the supremacy of concrete and steel.

wooden skyscraper

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Situated on the Bergen waterfront, The Tree is the tallest wooden building in the world. The 52.8 metre high structure is one of a growing number of so-called Plyscrapers altering city skylines. The timber industry say it’s an environmental solution, as countries seek to reduce emissions.

It will never totally displace concrete and steel, but it’s definitely a part in our solution towards our struggle towards a CO2 neutral society,”  says Ole Herman Kleppe, Chief Project Manager.

The architects insist that fears of fire in such timber homes are groundless.  “These columns and these CLT panels they don’t burn. They’re so thick that they don’t burn. In addition, they are painted with fire resistant paint and the house is sprinkled so we have all possible ways to prevent a fire in the house. So actually, this is the safest house in Bergen regarding fire.” explains Kleppe.

The 14-storey structure is made of sustainable wood. But concrete makers dispute the idea that timber is greener, insisting that deforestation causes more CO2 emissions. The Tree’s structure isn’t entirely wooden.

It’s concrete on this roof because it adds weight and it was necessary to add weight to this wooden building because it kind of dampens the swinging,” adds Per Reigstad, architect at Artec.

Later this year a wooden building that’s two inches taller will open in Vancouver. Even taller structures are being planned in Vienna and London.

Source: http://www.reuters.com/

Bones and Shells, Inspiration For New Materials

Researchers at MIT are seeking to redesign concrete — the most widely used human-made material in the world — by following nature’s blueprints. In a paper published online in the journal Construction and Building Materials, the team contrasts cement pasteconcrete’s binding ingredient — with the structure and properties of natural materials such as bones, shells, and deep-sea sponges. As the researchers observed, these biological materials are exceptionally strong and durable, thanks in part to their precise assembly of structures at multiple length scales, from the molecular to the macro, or visible, level.

From their observations, the team, led by Oral Buyukozturk, a professor in MIT’s Department of Civil and Environmental Engineering (CEE), proposed a new bioinspired, “bottom-upapproach for designing cement paste.

bones molecular structure

These materials are assembled in a fascinating fashion, with simple constituents arranging in complex geometric configurations that are beautiful to observe,” Buyukozturk says. “We want to see what kinds of micromechanisms exist within them that provide such superior properties, and how we can adopt a similar building-block-based approach for concrete.”

Ultimately, the team hopes to identify materials in nature that may be used as sustainable and longer-lasting alternatives to Portland cement, which requires a huge amount of energy to manufacture. “If we can replace cement, partially or totally, with some other materials that may be readily and amply available in nature, we can meet our objectives for sustainability,” Buyukozturk says.

Source: http://news.mit.edu/2016/