Microstructure and Strength Formation Mechanism of Waste White Sludge and Its Stabilized Materials

Abstract

In order to study the application of alkali-making waste white sludge as filler or binder in highway engineering, the micro-structure characteristics of alkali-making waste white sludge and binder stabilized waste white sludge were observed, and the strength formation mechanism was analyzed. The results show that white sludge consists of crystalline calcium sulfate crystal and calcium carbonate crystal. Acicular aragonite crystal increases and transforms into stable massive calcite with the increase of age, the crystals aggregate together and form a spatial network structure. A large number of crystals stacked with CSH gel, filling the crystal pores, increasing the cementation between aggregate particles, and migrating CO32- and SO42- ions to inert aggregates. Waste white sludge can be used as filler of asphalt mixture, which significantly improved the water stability and durability of asphalt mixture. It would provide data support and theoretical basis for regeneration of Alkali-making waste white sludge in the pavement.