Use of sulphate containing sieve sands in building materials

This paper discusses the results of a research project into the use of the fine fractions of demolition wastes for the production of building materials. Often, these wastes contain high amounts of leachable sulphate, which prevents application in an unbound form due to the criteria of the Dutch Building Materials Decree. In order to reduce sulphate leaching, solidification processes were developed to chemically immobilise the sulphate in the form of ettringite. Two types of building materials were developed: a road base construction material, and a concrete product for use as so-called mega blocks. A number of hydraulic binders have been tested for these purposes. For both types of application, products can be made that fulfil both engineering demands and leaching criteria.