The mechanical stability of cellular structures

logo_smallIn a previous post we already reported about acoustic emission experiments on cellular glass. The experiments are described in a public scientific paper.  This paper was in the mean time 96 times cited, which is a nice result. Indeed, people found the same phenomena in the crumbling of paper, in bundles of glass fibres, in theoretical simulations and in earthquakes. The citations can be found here with GOOGLE SCHOLAR. This service is invented to satisfy the ego of scientists, also mine. Like can be observed, even in 2014 after more than 15 years, the paper is still cited and this year, an important paper was found by the system.

The paper describes tensile experiments monitored with acoustic emission on polyurethane foams. They found the following similarities:

  • power law distribution for the magnitudes of the events
  • Power law distribution for the time between events
  • almost no dependence on the density

The second power law is not present at lower temperatures, which is unexpected. At lower temperature where the foam is brittle, I would expect even more similarities.

But the paper focuses on the fact that cellular structures fail in a different way than the base material, explaining why a seriously reduced safety factor can be used. In cellular glass, this is an important property when we think about cellular glass under buildings, under large tanks with liquid gasdgc new anhydrous ammonia tank c5648-00051 and the intelligent GLAPOR® solution under buildings with boards and gravel. PeriBo RDS-SD GLAPOR PICT Button

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Building with foamed glass gravel and boards

logo_smallFor years and years, I worked on the annealing of cellular glass to avoid breakage and producing foamed glass gravel is totally the opposite. But since 15 months, I daily watch the production of gravel and the product started to become very interesting to me. Indeed, in floor insulation is vapor tightness not an issue and the much more expensive horizontal boards are not necessary. Foamed glass gravel is also a durable solution for floor insulation and a nice method to use waste glass which became difficult to reuse as bottles or flat glass. On top of that, the waste glass can be foamed with healthy foaming agents, used in any house man or wife. The product does not absorb water, is 100% ecological and healthy and has a very long life time, compared to EPS and XPS. The last property is much more important under the floor (impossible to replace) than on a roof. Many companies are producing this material, which became rather cheap due to the market competition.

GLAPOR® is the only company, who is producing gravel and boards and has developed the best of two worlds. Indeed, in the GLAPOR® solution, the gravel is enclosed between walls, built from GLAPOR® cellular glass boards. In this way, rain water, falling aside the house, can not flow into the gravel, which is protected by the boards. In this way, the system has a perfect frost protection and other advantages. A schematic drawing and picture explain the above. The GLAPOR® mantra   “Fascination by glass bubbles” is well applied in this case.

Today, the gravel is sold at about 40€/m³ and the cellular glass boards at 150€/m³, making this system really competitive with the classic EPS and XPS solutions.

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Gravel between upstanding boards

perimeter

Actual building site with gravel between boards

The revelation of GLASSTEC 2014

logo_smallEvery two years, there is the glass technology fair in Düsseldorf20141022_110049. It is not my favorite exercise, certainly in times when float glass industry is suffering. But I was surprised by the many presentations about cellular glass, like for example Francke. They are working together with Glamaco Maschinenbau, a company which was working for the old Coriglas plant in Schmiedefeld, Germany. But another demonstration was astonishing. Indeed, Lfg or Lehr for Glass, who has built the plant for STES in Vladimir in Russia, had a nice 3D model of a production line, together with a movie of the running line and produced cellular glass. The produced cellular glass had extremely fine cells for such a light block. The first line was successfully started and the second line will be running in two weeks, together producing about 100000m³. Oleg Gerberv.!, owner of Lfg, was very proud he did the job with ordinary robots, who are very flexible to program and easy to replace in case of failure.  Oleg, a real Ukrainian, was working a long time for Ernst Pennekamp GmbH&Co, a glass lehr constructor and he decided to make the big jump. He found the capital and he did it, I have a large respect for this self made man. Some time ago, he asked my opinion about his robot, running in a pilot plant in Wuppertal, Germany. I still remember that visit, it was the first time I saw a white powder to be foamed to a nice black foam in an electric furnace under air. I realized I made an error 7 years ago, when I was thinking that cellular glass was at the end. Indeed, we are at the beginning of new challenging wave.

It was a long time very quite in the cellular glass business but the last seven years, a huge extra production capacity for boards was built in Europe, China and Russia. STES should sell their material NEOPORM about 40% cheaper than other manufacturers for the same quality and still with good profits. Next to that, we have at least 1000000 m³ foamed glass gravel, used for floor thermal insulation. STESThis is the start of important price drops, making cellular glass accessible to everybody, who likes to behave ecological and wanted to avoid foams with a rather short life time. Andrei from STES and Oleg from LFG are doing the same as for example Michael O’Leary from Ryan Air for the aviation industry. Thanks to him and other price breakers, ordinary people can take the air plane while in the past, it was reserved for the happy few without any good reason. Thanks Andrei and Oleg, you both are great guys.