“A suitable pozzolan used in appropriate amounts substantially increases resistance of concretes to sulfate attack…….Most effective are the pozzolans high in opal.”

Raymond E. Davis, Director, Engineering Materials Laboratory, University of California, Berkeley

“Those that are high in opal, such as diatomaceous earths and opaline shales, are much more effective than those high in glass, such as pumicites and fly ashes.”

Raymond E. Davis, Director, Engineering Materials Laboratory,
University of California, Berkeley

“From the results of many laboratory investigations and of field applications of pozzolans, it can be concluded that the addition of suitable pozzolanic materials in appropriate amounts to Portland cement concrete would be of benefit in nearly all types of construction. The effectiveness in improving workability, reducing bleeding and segregation, and in lessening the cracking tendency of concrete would indicate that these materials should be used far more widely than they are at present.”

Milos Polvika, Professor of Civil Engineering,
University of California, Berkeley

“Workability was the biggest advantage of using pozzolan. It really aided the pumping. I’ve never seen such a workable mix as this one.”

Dave Schmidt, Laboratory Chief, Bureau of Reclamation
Pacheco Tunnel Project

“Another important benefit of using pozzolan was that we got significantly less shrinkage cracking than we would have using a straight cement mix. This is due to the low heat of hydration.”

Dennis C. McCarry, Project Manager
Pacheco Tunnel Project