Eco-cements

The eco-cement studied in the CINDERELA project consists in the obtention of Supplementary Cementitious Materials (SCM) through the milling of inert SRM from CDW (glass, ceramic and concrete) and the mixing with commercial cement. The recycled inert SRM can be employed by direct replacement of Clinker during the cement production (up to 20% of replacement) or as a SCM directly employed in the manufacturing of cement-based products (up to 7% of cement replacement). In both scenarios, due to the cementitious activity of the milled SRM, the mechanical, chemical and physical properties of the commercial products are preserved or even improved.

The original CDW with moistures under 1% are grounded in a ball grinder to a particle size of <63 µm. 

Once obtained the grounded CDW (powder), a supplementary cementitious material is obtained. This recycled SCM is employed for the preparation of the eco-cements by replacing between 5 % and 7 % of the commercial Ordinary Portland Cement. The recycled SCM and the commercial OPC are blended in a high speed power mixer.

During the CINDERELA project, it has been proven and confirmed the most viable SRM from CDW and the characteristic that should fulfil the SRM in order to be employed as Supplementary Cementitious Material for the manufacturing of new eco-cement with reduced clinker content.

It was concluded that:

-          The most viable micronized SRM corresponds to the recycled concrete stream.

-          The fineness should be lower than 63 µm (the most similar to the fineness of the cement).

-          The maximum cement replacement should not exceed the 7%. The optimal cement replacement (direct replacement) is between 5 and 7%.

The replacement process can be done by direct replacement of a commercial cement (micronizing the SRM and mixing it with the cement).