The Use of Secondary Gypsum to Make a Controlled Low Strength Material

Abstract

This paper reports on the use of secondary minerals to make Controlled Low Strength Materials for trench or mine backfill. The mixes used red titanogypsum which is a by-product of titanium dioxide pigment production. A number of other secondary minerals were considered for mixing with the gypsum and steel slag from the basic oxygen process was found to be most successful. An optimised mix was developed and a site trial was carried out. The results showed a good performance but the failure of one test sample during curing showed that the material may not be suitable for other applications.