Concrete products based on a binder matrix produced with low CO₂emissions

Figure: Seiffarth, Hohmann, Kaps

Clay mineral contents of the clay raw materials in wt.-%

Figure: Seiffarth, Hohmann, Kaps

Pozzolanicity (Chapelle test) of the MetaClays thermally activated at temperatures between 550 and 950 °C

Figure: Seiffarth, Hohmann, Kaps

Strength activity index of the mortar prisms with cements blended with 15, 30, or 50 wt.-% of MetaClay (M1-M5), M6 not shown because of its low pozzolanicity

Figure: Seiffarth, Hohmann, Kaps

Figure: F. C. Nüdling Betonelemente

Demolded concrete pavers (core mix with 100 wt.-% of MetaClay M4, face mix with 100 wt.-% of CEM II A-S/42.5 R)

Figure: F. C. Nüdling Betonelemente

Figure: Seiffarth, Hohmann, Kaps

Strength activity index of the mortar prisms with cements blended with 40 or 60 wt.-% of industrially produced MetaClay M4

Figure: Seiffarth, Hohmann, Kaps

Cement production generates substantial CO₂ emissions that adversely affect the environmental footprint of concrete. In a research project, cement was replaced with MetaClay, and a commercially attractive concrete paver was developed.

Cement production is characterized by process temperatures in excess of 1.300 °C and substantial CO₂ emissions; about 60 % of these emissions are attributable to limestone neutralization [1]. These emissions deteriorate the carbon footprint, and thus reduce the commercial potential, of building materials that use cement as a binder, including concrete.

For this reason, the use of thermally activated clays or MetaClays as alternative binders in cementitious building materials has been investigated with great interest in the past few years. MetaClays are produced at much lower temperatures on the...