MSGID: 1:317/3 643f6e6d   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Researchers develop carbon-negative concrete    
      
     Date:   
         April 18, 2023   
     Source:   
         Washington State University   
     Summary:   
         A viable formula for a carbon-negative, environmentally friendly   
         concrete that is nearly as strong as regular concrete has been   
         developed. In a proof-of-concept work, the researchers infused   
         regular cement with environmentally friendly biochar, a type   
         of charcoal made from organic waste, that had been strengthened   
         beforehand with concrete wastewater.   
      
         The biochar was able to suck up to 23% of its weight in carbon   
         dioxide from the air while still reaching a strength comparable   
         to ordinary cement. The research could significantly reduce carbon   
         emissions of the concrete industry, which is one of the most energy-   
         and carbon-intensive of all manufacturing industries.   
      
      
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   FULL STORY   
   ==========================================================================   
   A viable formula for a carbon-negative, environmentally friendly concrete   
   that is nearly as strong as regular concrete has been developed at   
   Washington State University.   
      
      
   ==========================================================================   
   In a proof-of-concept work, the researchers infused regular cement with   
   environmentally friendly biochar, a type of charcoal made from organic   
   waste, that had been strengthened beforehand with concrete wastewater. The   
   biochar was able to suck up to 23% of its weight in carbon dioxide from   
   the air while still reaching a strength comparable to ordinary cement.   
      
   The research could significantly reduce carbon emissions of the concrete   
   industry, which is one of the most energy- and carbon-intensive of all   
   manufacturing industries. The work, led by doctoral student Zhipeng Li,   
   is reported in the journal,Materials Letters.   
      
   "We're very excited that this will contribute to the mission of   
   zero-carbon built environment," said Xianming Shi, professor in the WSU   
   Department of Civil and Environmental Engineering and the corresponding   
   author on the paper.   
      
   More than 4 billion tons of concrete are produced every year   
   globally. Making ordinary cement requires high temperature and   
   combustion of fuels. The limestone used in its production also goes   
   through decomposition which produces carbon dioxide, so that cement   
   production is thought to be responsible for about 8% of total carbon   
   emissions by human activities worldwide.   
      
   Researchers have tried adding biochar as a substitute in cement to   
   make it more environmentally friendly and reduce its carbon footprint,   
   but adding even 3% of biochar dramatically reduced the strength of the   
   concrete. After treating biochar in the concrete washout wastewater,   
   the WSU researchers were able to add up to 30% biochar to their cement   
   mixture. The paste made of the biochar- amended cement was able to reach a   
   compressive strength after 28 days comparable to that of ordinary cement   
   of about 4,000 pounds per square inch.   
      
   "We're committed to finding novel ways to divert waste streams to   
   beneficial uses in concrete; once we identify those waste streams, the   
   next step is to see how we can wave the magic wand of chemistry and turn   
   them into a resource," said Shi. "The trick is really in the interfacial   
   engineering -- how you engineer the interfaces in the concrete."   
   The caustic concrete washout water is a sometimes problematic waste   
   material from concrete production. The wastewater is very alkaline but   
   also serves as a valuable source of calcium, said Shi. The researchers   
   used the calcium to induce the formation of calcite, which benefits the   
   biochar and eventually the concrete incorporating the biochar.   
      
   "Most other researchers were only able to add up to 3% biochar to replace   
   cement, but we're demonstrating the use of much higher dosages of biochar   
   because we've figured out how to engineer the surface of the biochar,"   
   he said.   
      
   The synergy between the highly alkaline wastewater that contains a lot   
   of calcium and the highly porous biochar meant that calcium carbonate   
   precipitated onto or into the biochar, strengthening it and allowing   
   for the capture of carbon dioxide from the air. A concrete made of the   
   material would be expected to continue sequestering carbon dioxide for   
   the lifetime of the concrete, typically 30 years in pavement or 75 years   
   in a bridge.   
      
   In order to commercialize this technology, the researchers have been   
   working with the Office of Commercialization to protect the intellectual   
   property and have filed a provisional patent application on their   
   carbon-negative concrete work. They recently received a seed grant from   
   the Washington Research Foundation to produce more data for a variety   
   of use cases. They are also actively seeking industry partners from   
   the building and construction sector to scale up production for field   
   demonstrations and licensing this WSU technology.   
      
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Engineering_and_Construction # Construction #   
                   Organic_Chemistry # Graphene   
             o Earth_&_Climate   
                   # Air_Quality # Global_Warming # Forest #   
                   Recycling_and_Waste   
       * RELATED_TERMS   
             o Concrete o Carbon_dioxide o Carbon_dioxide_sink o   
             Carbon_monoxide o Forest o Carbon_cycle o Activated_carbon   
             o Ocean_acidification   
      
   ==========================================================================   
   Story Source: Materials provided by Washington_State_University. Original   
   written by Tina Hilding. Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Zhipeng Li, Xianming Shi. Towards sustainable industrial   
      application of   
         carbon-negative concrete: Synergistic carbon-capture by concrete   
         washout water and biochar. Materials Letters, 2023; 342: 134368 DOI:   
         10.1016/ j.matlet.2023.134368   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/04/230418101419.htm   
      
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