Akademik Veri Yönetim Sistemi
STRUCTURAL CONCRETE, 2025 (SCI-Expanded, Scopus)
This study investigates the effects of reclaimed asphalt pavement (RAP) aggregates and silica fume (SF) on the mechanical, durability, and microstructural properties of fly ash (FA)-based geopolymer composites (GC) under varying curing conditions. GCs were prepared with RAP contents of 0%, 15%, 30%, and 60% as replacements for river aggregate (RA) and with partial replacement of FA by 15% SF. Samples were cured at 60 degrees C and 90 degrees C, and their performance was evaluated through compressive and flexural strength tests, freeze-thaw (F-T) resistance, high-temperature exposure, sorptivity, porosity, and microstructural analysis. The results reveal that substituting RA with 15% RAP demonstrated the optimal content for enhancing compressive strength, with increases of 33.64% at 60 degrees C and 8.04% at 90 degrees C. At 30% RAP, the improvements were smaller (7.36% at 60 degrees C and 7.37% at 90 degrees C), while 60% RAP led to strength reductions of 0.97% and 8.12% at 60 degrees C and 90 degrees C, respectively. The mixture containing 100% FA and 15% RAP as a replacement for RA demonstrated the best high-temperature performance, exhibiting the lowest strength loss at 750 degrees C. The lowest strength loss after 50 F-T cycles was observed in the mixture cured at 90 degrees C with 30% RAP and 100% FA. Mixtures with 100% FA and 30% RAP cured at 90 degrees C exhibited the lowest strength loss after 50 F-T cycles, demonstrating enhanced durability. Mixtures containing 100% FA exhibited superior F-T performance with the incorporation of RAP compared with the reference mixture without RAP, irrespective of curing temperature. Mixtures with 100% FA and 15% RAP demonstrated the highest resistance to elevated temperatures, with minimal strength loss at 750 degrees C. However, increasing RAP content to 30% and 60% led to greater deterioration due to thermal degradation of bitumen-coated aggregates. Replacing FA with 15% SF significantly reduced high-temperature resistance, causing over 90% strength loss at 750 degrees C.