volcanic tuff as substitute for portland flyash cement

jordan wong:

I am doing a research on this topic for my final year project,meaning that i will add volcanic tuff to cement. May i know if anyone who ever do research in this topic that have information to share with me? i have a few questions here..

1. Do i need to have heat treatment for the volcanic tuff ?

Some tuff minerals have been shown to exhibit increased pozzolanic activity after heat treatment at 500°C - 800°C.(eg. phillipsite, suevite)  Whether you need to heat-treat a particular tuff depends on the type and quantities of minerals present. 

See the paper at http://tiny.cc/dd96v

jordan wong:

2. What is the mixing proportion? 

 Again, the mixing proportion will depend on the type of volcanic tuff used and the concrete properties desired. In practice this can only be optimised by laboratory and plant trials.

Regards,

Ted.