Compressive strength and durability properties of roller-compacted concrete pavement containing electric arc furnace slag aggregate and fly ash

Abstract

This study investigates the effects of electric arc furnace (EAF) slag aggregate and fly ash on compressive strength and durability properties (i.e. water absorption, abrasion resistance, and sulfate resistance) of roller-compacted concrete pavement (RCCP). The EAF slag aggregate as natural aggregate substitution was used at three levels (i.e. 0%, 50%, and 100%) and cement was replaced by fly ash at three ratios (i.e. 0%, 20%, and 40%). The EAF slag aggregate used in this study was exposed to outdoor condition for several months to reduce the volume instability. The RCCP mixing proportions were determined by soil compaction method. The compressive strength of RCCP was examined at 3-, 7-, 28-, and 91-day age. Meanwhile, the water absorption, abrasion resistance, and sulfate resistance of RCCP at 91-day age were used to study the durability properties. Furthermore, the length change of mortar bars made with EAF slag aggregate was measured to evaluate the expansive potential of EAF slag caused by autoclave condition and alkali-silica reaction (ASR) condition. Additionally, X-ray diffraction analysis was offered to identify the crystalline phases of mortar patterns under autoclave and ASR testing condition. The results presented that the compressive strength and sulfate resistance of RCCP containing EAF slag aggregate declined slightly, whereas the water absorption and abrasion resistance increased in comparison to those of traditional RCCP. Besides, the use of fly ash as cement substitution improved the compressive strength of slag-RCCP at long-term age. A replacement of 20% fly ash provided the slag-RCCP fulfilling the strength and durability requirements for pavement. In addition, the expansion in terms of length change of mortar bars indicated that EAF slag aggregate after the proper treatment performed the volume stability under the autoclave condition and ASR test.