Abstract: It is a challenge to deal with the scrap tyre all over the world. Reusing the scrap tyres in the geotechnical engineering provides an effective way of controlling pollution. The aim of the tests is explore the application of the scrap tyres to improving soils. A series of tests at different high stress levels is conducted on completely decomposed granite (CDG) sand and tyre rubber (granular rubber and rubber fibre) mixtures. The compression behaviour of the mixtures with different rubber percentages and different shapes of tyre rubber particle are analysed. The effect of the rubber particle on the breakage of sand particle in the mixture is investigated during compression. It is concluded that the normal compression line (NCL) can be found in each the mixture. The compression and rebound significantly increase as the rubber percentage is over 20%, which are not affected with the shape of rubber particle. There is less breakage in the mixture with higher rubber contents. Meanwhile, the larger size of the sand particles, the more breakage of the sand in the mixtures.

Key words: scrap tyre, completely decomposed granite sand, one-dimensional compression test, particle breakage