Wastepaper Sludge Ash and Acid Tar as Activated Filler Aggregates for Stone Mastic Asphalt

Abstract

Nowadays, the most common ways to dispose of acid tars and paper production waste are burial or incineration, but it is ecologically and economically expedient to use such waste in building materials. A new variant of filler aggregate—wastepaper sludge ash (paper production waste) and a chemical activator for filler aggregates—acid tar (oil-refining industry waste) is proposed. Elemental and mineralogical compositions of wastepaper sludge ash for comparison with commodity limestone mineral powder are established. Chemical activation of wastepaper sludge ash and limestone mineral powder was carried out and the wetting properties of the obtained materials were investigated by means of primary and neutralized acid tar. The physical and mechanical properties of stone mastic asphalt samples with different filler aggregate variants were studied. The possible chemical transformations in stone mastic asphalt using limestone mineral powder and wastepaper sludge ash activated by acid tar are shown. The possibility of replacing traditional limestone mineral powder with industrial wastepaper sludge ash has been proven, and the effectiveness of activating filler aggregates by acid tar has been confirmed. It was established that acid tar as an activator for filler aggregates does not require neutralization because stone mastic asphalt, in this case, demonstrates better properties compared to acid tar neutralization. As a result of our research, the application of wastepaper sludge ash is possible as a filler aggregate for stone mastic asphalt. And to obtain improved stone mastic asphalt characteristics, wastepaper sludge ash is required to activate 5 wt.% acid tar.