self-consolidating concretes incorporating high...

Self-consolidating concretes incorporating high-volume natural pozzolan

Goal of the research

To compare the effects of Portland cement replacement with natural pozzolan on the strength and durability of self-consolidating concretes

K. Celik, M. D. Jackson, M. Mancio, C. Meral, A. M. Emwas, P. K. Mehta, P. J. M. Monteiro, High-volume natural volcanic pozzolan and limestone powder as partial replacements for portland cement in self-compacting and sustainable concrete, Cement & Concrete Composites 45 (2014) 136–147.

Pozzolan: optical microscopy

Chemical composition of the materials

Concrete Mix Proportions

Compressive strength

Durability tests

Microstructural Studies

K. Celik, M. D. Jackson, M. Mancio, C. Meral, A. M. Emwas, P. K. Mehta, P. J. M. Monteiro, High-volume natural volcanic pozzolan and limestone powder as partial replacements for portland cement in self-compacting and sustainable concrete, Cement & Concrete Composites 45 (2014) 136–147.

Microstructural Studies

Summary

� Finely-ground natural basaltic ash pozzolan with or without finely-ground LS provides an effective high volume substitute for up to 50% by mass OPC in experimental concretes with good workability, which satisfy self-compacting concrete criteria without costly viscosity-modifying admixtures.

Summary

� Cementitious hydrates in the interfacial zone along the rims of gel-palagonite particles have Ca/(Al + Si) = 0.4–0.6 and Na + Mg + K + Ti + Fe/(Al + Si) = 0.6–0.7, which reflect the lower calcium and higher alkali concentrations of the reacting basaltic glass relative to OPC.

Summary

� The composition of C–A–S–H in the binding cementitious matrix vary from Ca/(Al + Si) = 0.70–1.9, which seem to reflect relative proximity to partially reacted gel-palagonite particles and the overall proportion of NP in the cement mix