What are the Pozzolans used in the production of Green Concrete?

  • There are no better definitions concerning Pozzolans than those offered by the Amercian Concrete Institute. The basic issue to remember is the fact that pozzolans are the ashes of Soil and Coal, the waste materials after burning coal for electricity.  Natural pozzolans would be volcanic ash.
  • Cement, portland-pozzolan – a hydraulic cement consisting of an intimate and uniform blend of portland cement or portland blast-furnace slag cement and fine pozzolan. Produced by intergrinding portland-cement clinker and pozzolan, by blending portland cement or portland blast-furnace slag cement and finely divided pozzolan, or a combination of intergrinding and blending, in which the pozzolan constituent is within specified limits.
  • Cement, portland blast-furnace slag – a hydraulic cement consisting of an intimately interground mixture of portland-cement clinker and granulated blast-furnace slag or an intimate and uniform blend of portland cement and fine granulated blast-furnace slag in which the amount of the slag constituent is within specified limits.
  • Pozzolan – a siliceous or siliceous and aluminous material that in itself possesses little or no cementitious value but that will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds having cementitious properties; there are both natural and artificial pozzolans.
  • Why discuss pozzolans? Because these wastes are going into concrete and not to landfills or storage bays built to dispose of the waste ashes. These new green standards are affecting the quality of concrete.