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Bei KELLER auf der CERAMITEC 2018

   Die diesjährige CERAMITEC, auf der vom 10. bis 13. April in München über 600 Aussteller vertreten waren, war für KELLER ein großer Erfolg. Mit einer neuen Organisation der Geschäftsbereiche und in neuem Design wurden auf dem stylischen Messestand sehr gute Gespräche mit Kunden aus mehr als 40 Nationen geführt. Damit wurde die Erwartungshaltung noch übertroffen.

High-tech methods reveal new insights into strength of Roman concrete

A drilling project at a marine structure in Portus Cosanus, Tuscany, in 2003 yielded Roman concrete samples that have revealed important insights into the durability of the ancient material.

  Pozzolanic reaction of volcanic ash with hydrated lime is thought to dominate the cementing fabric and durability of 2000-year-old Roman harbor concrete. Pliny the Elder, however, in first century CE emphasized rock-like cementitious processes involving volcanic ash (pulvis) “that as soon as it comes into contactwith the waves of the sea and is submerged becomes a single stone mass (fierem unum lapidem), impregnable to the waves and every day stronger” (Naturalis Historia 35.166).

   Pozzolanic crystallization of Al-tobermorite, a rare, hydrothermal, calcium-silicate-hydrate mineral with cation exchange capabilities, has been previously recognized in relict lime clasts of the concrete. Synchrotron-based X-ray microdiffraction maps of cementitious microstructures in Baianus Sinus and Portus Neronis submarine breakwaters and a Portus Cosanus subaerial pier now reveal that Al-tobermorite also occurs in the leached perimeters of feldspar fragments, zeolitized pumice vesicles, and in situ phillipsite fabrics in relict pores. Production of alkaline pore fluids through dissolution-precipitation, cation-exchange and/or carbonation reactions with Campi Flegrei ash components, similar to processes in altered trachytic and basaltic tuffs, created multiple pathways to post-pozzolanic phillipsite and Al-tobermorite crystallization at ambient seawater and surface temperatures.

Dřevo tvrdé jako ocel

  Dřevo je levný a užitečný materiál, ovšem nepříliš tvrdý, což ho pro některá využití diskvalifikuje. Vědci nyní ale vyvinuli postup, kterým lze slisovat dřevo tak, aby bylo tvrdé jako ocel, ale zároveň mnohem lehčí a levnější. Nový materiál slibuje možnosti širokého využití, zatím je ale výroba náročná.
Tým výzkumníků z Marylandské univerzity vyvinul poměrně jednoduchý postup, jak slibný materiál vytvořit. Dřevo nejprve čeká chemická lázeň: výzkumníci využili roztok hydroxidu sodného a siřičitanu sodného, ve kterém dřevo vařili 7 hodin. Tím byla ve dřevě zachována celulóza, ale odstraněny některé polymery, včetně části ligninu, který ve dřevě zpevňuje buněčné stěny.

Strengthening wood to replace concrete in construction

   Concrete is an impressive materiál; it  is much more complex than its unassuming dull gray surface might suggest. With recent advances in computational modeling and molecular analysis techniques, scientists have been active in an effort to better understand concrete’s strength. Ultimately, that knowledge can help to boost the strengthand reduce the high environmental impact of concrete-its huge carbon footprint: current concrete manufacturing accounts for 8%–9% of anthropogenic CO2 emissions and 2%–3% of global primary energy.

New Concrete Safer During Disasters

 


Dr Alan Richardson, of Northumbria University.               Credit: Northumbria University

 

  Researchers are developing a new type of concrete that could significantly lower death tolls during bomb blasts, earthquakes and other disasters.

The international team- comprised of researchers from the U.K., India and Canada -are working to create a tougher form of concrete using 3D fiber reinforcement rather than the traditional 2D variety.

Advance in Testing Micro-Scale Compressive Strength of Cement

Experimental setup for applying micropillar compression        Photo J.W. Dixon


 Researchers from North Carolina State University have, for the first time, used a “micropillar compression” technique to characterize the microscale strength of cement, allowing for the development of cement with desirable strength properties for civil engineering applications. “The information collected using this technique can be used to better understand the behavior of concrete when it fails, as well as providing key data for ‘constitutive’ models that are used for designing and determining the safety of large-scale civil engineering structures,” says Rahnuma Shahrin, a civil engineering Ph.D. student at NC State and lead author of a paper on the work.

Sea urchin-inspired cement could enable more fracture-resistant concrete

 Nature loves a good brick and mortar-style construction. And that’s for good reason—it’s one of the toughest designs you can get, combining both strength and flexibility.
 For instance, nacre (aka mother of pearl) uses stacks of aragonite nanoplatelet bricks to provide strength to this super strong biomaterial. The goal here is not necessarily to prevent cracking altogether—but rather to prevent a crack from catastrophically propagating through the entire material. Although the brick material in a brick-and-mortar design may crack, a softer in-between mortar material helps absorb crack energy, preventing in from ripping through the entire material.
 Sea urchins use a similar strategy to build their spines, layering hard, crystalline calcite blocks with softer, amorphous calcium carbonate materials. Such bioinspired engineering principles have been used before to design stronger glass or ceramicmaterials, but could they be applied to build better cement, too?

Stronger concrete by adding plastic flakes

  Discarded plastic bottles could one day be used to build stronger, more flexible concrete structures, from sidewalks and street barriers, to buildings and bridges, according to a new study. MIT undergraduate students have found that, by exposing plastic flakes to small, harmless doses of gamma radiation, then pulverizing the flakes into a fine powder, they can mix the irradiated plastic with cement paste and fly ash to produce concrete that is up to 15 percent stronger than conventional concrete.
  Concrete is, after water, the second most widely used material on the planet. The manufacturing of concrete generates about 4.5 percent of the world’s human-induced carbon dioxide emissions. Replacing even a small portion of concrete with irradiated plastic could thus help reduce the cement industry’s global carbon footprint. Reusing plastics as concrete additives could also redirect old water and soda bottles, the bulk of which would otherwise end up in a landfill. 

HeidelbergCement to sell its calcium silicate unit business

HeidelbergCement announces that it has signed an agreement with H+H International A/S and its subsidiary H+H Deutschland GmbH to sell its German and Swiss calcium silicate unit business (“HDKS”). The enterprise value of the transaction amounts to about € 110 million. HeidelbergCement expects the transaction to close in the first quarter of 2018.
 “HDKS has a strong market position in the North-East and South-West of Germany as well as in Switzerland, but the focus of its product portfolio on calcium silicate units is outside the core businesses of HeidelbergCement,” said Dr. Bernd Scheifele, CEO of HeidelbergCement. “The disposal is part of our portfolio review and optimization with the goal to generate additional cash flow in order to support our disciplined growth and increase shareholder returns.”

Infrastruktura ČR se vzdaluje úrovni EU

Stavebnictví nedokázalo využít fondy EU 
 

Petr Zahradník

   Stavebnictví, a obzvláště inženýrské stavitelství, má v českých podmínkách nevšední potenciál. Díky stávajícímu systému financování může náklady na řadu českých projektů hradit ve velké míře západoevropský daňový poplatník prostřednictvím fondů EU.
   Pokud stavebnictví dobře funguje, má mezi všemi ekonomickými činnostmi druhý nejvyšší synergický efekt. Navíc je v jinak mimořádně otevřené ekonomice málo dovozně náročné. Může za to především veřejný sektor, jenž nedokáže skloubit ohromný objem peněz s věcnými požadavky na jejich uvolnění tak, aby byl dárce spokojen.

Ceny bytů v Česku dále rostou

foto :E 15

Prodejní ceny bytů v Praze a v krajských městech ČR vzrostly ve 2. čtvrtletí letošního roku meziročně o 10,7 procenta na 49.800 korun za metr čtvereční. Nejdražší byla Praha s průměrnou cenou 65 700 korun, naopak v nejlevnějším Ústí nad Labem to bylo 11 800 korun.
Vyplývá to z údajů portálu CenovaMapa.org, které dnes zveřejnila poradenská společnost Deloitte. Portál zpracovává informace o skutečných prodejních cenách přímo z kupních smluv evidovaných v katastru nemovitostí.

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Kalendář

10.09.2018 - 12.09.2018
Refractory Raw Materials
Shanghai/CN
23.09.2018 - 26.09.2018
Innovations in Glass and Glass Technology
Yokohama/Jap
26.09.2018 - 28.09.2018
DE Materials Science and Engineering Congress
Darmstadt/DE
26.09.2018 - 27.09.2018
61.Int.Colloquium on Refractories
Aachen/DE
9.10.2018 - 10.10.2018
Suroviny
Praha/CZ
23.10.2018 - 26.10.2018
GLASSTEC 2018
Dusseldorf/DE
25.06.2019 - 29.06.2019
Gifa-Metec-Thermprocess-Newcast
Duesseldorf/DE
13.10.2019 - 16.10.2019
16.Congress UNITECR 2019
Yokohama/JP