Comparison of granitic and volcanic aggregates for making high strength concrete in Hong Kong

Abstract

Both granitic and volcanic aggregates are being used for concrete in Hong Kong. Granitic aggregate is more common because of historical reasons. With the advent of high strength concrete, however, it is gradually realized that the relatively low intrinsic strength of the granitic aggregate is a limiting factor for concrete strength. The volcanic aggregate, which is generally stronger, may be better for producing higher strength. concrete. In this study, parallel tests on the two types of aggregates are carried out to investigate the effects of using the different aggregates on concrete strength, and to determine the highest concrete strength achievable with each of them. Certain problems with the volcanic aggregate are identified and possible improvements in concrete properties by overcoming these problems are investigated.