Papers by Author: Guang Liang Gao

Abstract: The magnesium slag is discarded from production of magnesium metal from dolomite. However the magnesium slag is slaked in some factories by means of sprinkling water to prevent from dust pollution. The possibility of slaked magnesium slag (SMS) to play a role of raw material and blend for portland cement was investigated by experiments of raw mix preparation, clinker calcining and property determination of cement pastes and mortars. The results revealed that SMS was still reactive. The raw mix with SMS was of excellent burnability that would contribute to energy saving. As a raw material, SMS can be used for calcining clinker of good quality; and as a blend it is suitable for production of ordinary portland cements. Because the magnesium slag is slaked, SMS has no problem on soundness. Higher strength of cement can be obtained in form of binary blends consisting of SMS and ground granulated blast-furnace slag or fly ash.

Abstract: The demolished concretes have ever been considered as homogeneous materials and simply crushed to produce recycled aggregates which can only be used for low strength concretes. In mechanical processes of intergrinding in combination with pre-crushing, the sieve residue in each size fraction varies with grinding time and residue-grinding time curves of most fractions have their inflection points that can be considered as termination of separation. The original state aggregates (OSA) so recycled are up to standard of grade II original coarse aggregates specified in China’s standard Pebble and Crushed Stone for Building (GB/T 14685-2001) and can be applied in moderate strength concretes with a bit higher strength than that of original concretes from which the OSA derived. In this method, the OSA can be separated furthest from cement pastes and mortars while suffering minimum damage in separation processes and can retain higher strength.