Dredged Sand and Gravel for Construction Purposes-an Assessment Procedure and Hong Kong Case Study

Abstract

This paper discusses important features of various methods used to describe and specify sand and gravel with a view to Its being used for construction purposes. The paper presents the results of work done in Hong Kong to develop a scheme that might have general application for assessing onshore or offshore sand and gravel deposits in any country. The need for such a scheme became apparent with recent moves by the Hong Kong Government to more clearly specify sand in its Unified General Specification, and also with the recent discoveries of large resources of high quality granular materials in Hong Kong waters which might be suitable for various construction uses. A conclusion to the work on seabed materials that ensued and a key aspect of the assessment scheme which resulted, is that following detailed description of all the samples, selected Type Samples from different target geological deposits should be tested for compliance with particular specifications/standards. It is contended that primarily in this way can an inventory be compiled of those geological deposits that will satisfactorily provide resources for particular purposes. The alternative approach involving an initial detailed classification of the materials is not advocated.