Geopolymer Green Concrete

Untitled pictureOverviewGeopolymer concrete is a novel, environmentally friendly inorganic polymer made from a waste product—fly ash—of coal-fired power plants. In collaboration with local, national, and international partners, Erez Allouche and his team of researchers at the Trenchless Technology Center are developing a whole range of customized applications for this product as a replacement for Ordinary Portland Cement (OPC), the most common building material on the planet.Geopolymer concrete has a number of benefits. The first is it has the potential to substantially curb CO2 emissions. It can also produce a more durable infrastructure capable of lasting hundreds of years, instead of tens. And by utilizing the fly ash, it can conserve hundreds of thousands of acres currently used for disposal of coal combustion products, and protect our water ways from fly ash ‘contamination’, too. The geopolymer generates a lower carbon footprint and turns a waste stream for power plants into a product of value.In comparison to ordinary Portland cement (OPC), geopolymer concrete (GPC) has better resistance to corrosion and fire (up to 2400°F), high compressive and tensile strengths, a rapid strength gain, and lower shrinkage.
 
Benefits:
Compressive strength: 3,000 – 16,000 psi (depending on the geopolymer formulation used).
Flexural strength: Approximately twice that of OPC.
Chemical resistance: Two to Five times greater resistance to sulfuric acid attack compared with OPC; virtually immune to sulfate attack.
Porosity/Permeability: Ten times lower than OPC utilized in typical structural applications.
Strength gain: Full strength is gained within 1 to 3 days; 80% of ultimate strength is gained within 1 day.
Setting time: 15 to 120 minutes
Fire Resistance: Non-flammable non-combustible.
Carbon dioxide emission: 10% or less compared with OPC (i.e., 90% CO 2 emission reduction).
 
548189_229380800516492_6561024_n      Successful geopolymer development projects to date include
      High temperature-resistant and corrosion-resistant concretes
      Grouts for high-end refractory materials,
      Corrosion-resistant geopolymer formulations for coastal roadways, Bridges and flood control structures
      Spray-on concrete for manhole rehabilitation, and
      Flexible geopolymer concrete coatings for steel pipes and other critical steel structures.
What s Next
The flexible geopolymer is also being enhanced with halloysitenanotubes for added performance features. These new formulations  are creating the world’s first smart concrete with self-healing  properties.  Testing on the HTGeopolymerTM  in collaboration  with NASA and Aero Jet in their launching facilities at Stennis Space  Center has proven very successful. Local Ruston firm M.L. Smith, a leader in the refractory construction industry, has also been a  partner in the development of this product
Durability
Green concrete has a low to moderate resistance to corrosive environments relative to geopolymer concrete. In comparison to ordinary Portland cement, geopolymer concrete features greater corrosion resistance, substantially higher fire resistance (up to 2400° F), high compressive and tensile strengths, a rapid strength gain, and lower shrinkage.
 
Energy Consumption
The Portland cement production process is one of the most energy consuming mass production processes. A mixture of powdered raw materials requires heating to over 1400 C to obtain cement powder, with its corresponding high use of fuels. Geopolymer, on the other hand, can be produced out of waste products like fly ash, or out of calcined kaolin (meta-kaolin) which consumes significantly less energy.
 
Pollution and global warming
Actual production of Portland cement contributes 13.5 billion tons of carbon dioxide per year (1 ton of carbon dioxide for each ton of produced cement) which is equivalent to 7% of the total global emission of carbon dioxide to the atmosphere. Geopolymer is made out of waste materials like fly ash, therefore does not have an industry of itself, and does not contribute to carbon dioxide emissions.