Activation of natural pozzolan and use thereof

Abstract

An activated pozzolan composition includes a fine interground particulate blend of an initially unactivated natural pozzolan and a supplementary cementitious material (SCM) different than the initially unactivated natural pozzolan. The initially unactivated natural pozzolan may include volcanic ash or other natural pozzolanic deposit having a moisture content of at least 3%, and the activated pozzolan composition can have a moisture content less than 0.5%. The initially unactivated natural pozzolan may have a particle size less than 1 mm before intergrinding with the SCM. The SCM used to activate the initially unactivated natural pozzolan can be initially coarse or granular with a size greater than 1-3 micrometers and may include granulated blast furnace slag, steel slag, other metallurgical slag, pumice, limestone, fine aggregate, shale, tuff, trass, geologic material, waste glass, glass shards, basalt, sinters, ceramics, recycled bricks, recycled concrete, refractory materials, other waste industrial products, sand, or natural mineral.

Description

technical field [0001] The present invention relates generally to the field of supplementary cementitious materials, natural pozzolans, activation of natural pozzolans, and mixtures of natural pozzolans and other materials. Background technique [0002] Supplementary cementitious materials (SCMs), such as coal ash, metallurgical slag, natural pozzolan, biomass ash, post-consumer glass, and limestone, can be used to partially replace Portland cement in concrete. SCMs can be produced with increased slurry density, increased durability, lower heat of hydration, lower chloride ion permeability, reduced creep, increased resistance to chemical attack, lower cost and reduced Improved concrete for environmental impact. [0003] Natural pozzolans such as volcanic ash, pumice and other materials found on earth can be calcined and / or ground to increase pozzolan activity. Both processes consume a lot of energy. Grinding natural pozzolans can be difficult due to the hardness of volcan...

AI Technical Summary

Problems solved by technology

While the intergrinding of natural pozzolan with cement clinker can be performed in a single step and is therefore significantly less costly and more efficient than processing OPC and natural pozzolan separately and then mixing them together, the Performance is generally lower than that of non-intergrinding blends of individually processed components

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