Waste cement dusts as fillers for rubber compounds

The possibility of substitution of expensive active fillers, e.g. carbon black, for the waste products which can play the role of these fillers, e.g. the waste cement dusts or the waste post-HF silica, were investigated. The physico-chemical properties of the investigated waste cement dusts and the waste post-HF silica, as well as the strength properties of the rubber compounds containing these as fillers, were determined. To increase the activity and chemical affinity with the rubber, the waste cement dusts and the waste post-HF silica were modified by the use of adhesion promoters, that is alkoxysilanes. It was found that it would be possible to partly substitute carbon black for the waste cement dusts and the waste post-HF silica. The mixture ratio of a compound which had these wastes and showed the optimum strength properties was proposed.