APPLICATION OF CALCINED CLAY CONTAINING ALLOPHANE AND HALLOYSITE AS A SUPPLYMENTARY CEMENTIOUS MATERIALS

Abstract

In this study, volcanic glass powder, allophane, and halloysite were calcined and we evaluated performance as SCMs. Compared to the pre-calcination, there was no change in the compressive strength of calcined volcanic glass powder when used as SCMs, while the compressive strength of calcined allophane and calcined halloysite was greatly increased when used as SCMs. In addition, when using calcined allophane and halloysite, the replacement of limestone increased the compressive strength at 7 days, and the compressive strength at 28 days was comparable to that of the binder without limestone replacement. The reaction of calcined allophane and halloysite as SCMs with cement is found to be affected by the clay content and the presence of limestone.