A scanning electron microscope image shows spherical particles in type C
fly ash used by Rice University engineers to make cementless binder for concrete.
(Credit: Multiscale Materials Laboratory/Rice University)

   Ever since Joseph Aspdin heated powdered limestone and clay together in a furnace in the early 19thcentury, Portland cement has been the most commonly used type of cement in the world.

 However, cement, in general, has an image problem—it is not the most environmentally friendly material. Cement manufacturing represents nearly 5% of global CO2 emissions, according to the National Precast Concrete Association.

  We’ve reported on a few ways researchers are studying to make concrete greener, including incorporating irradiated plastic water bottles into cement paste and this research that uses graphene at the nanoscale to replace nearly half of the materials that go into the production of concrete.

Společnost Wienerberger AG získal holandského výrobce  cihel Daas Baksteen BV, rodinného výrobce obkladačských tvárnic s dlouhou historií.

 Daas Baksteen

Provozem dvou výrobních závodů poblíž německé hranice společnost vydělá přibližně 24 milionů EUR. a zaměstná dalších 125 pracovníků. Vyrábí  obkladové cihly a hliníkové dlaždice z vysoce kvalitních materiálů. V uplynulých letech rozvíjela rodinná firma také inovativní obkladové řešení jako ClickBrick a ID stěna v reakci na rostoucí poptávku po udržitelných a snadno instalovatelných stavebních systémech. S ohledem na více než dvě třetiny prodeje společnosti je Nizozemsko hlavním trhem pro produktové portfolio

   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.

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 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.

   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.

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.

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.

 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?

  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.