Zhumatay R., Yazıcı Ş., Özen S., Mardani A.
POLYMERS, cilt.18, sa.22, ss.1-38, 2026 (SCI-Expanded, Scopus)
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Yayın Türü:
Makale / Tam Makale
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Cilt numarası:
18
Sayı:
22
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Basım Tarihi:
2026
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Doi Numarası:
10.3390/polym18222837
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Dergi Adı:
POLYMERS
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Derginin Tarandığı İndeksler:
Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest), Science Citation Index Expanded (SCI-EXPANDED), Chemical Abstracts Core, Compendex, INSPEC
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Sayfa Sayıları:
ss.1-38
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Bursa Uludağ Üniversitesi Adresli:
Evet
Özet
Recycled construction-waste fine aggregates and polypropylene (PP) fibers can modify the ambient and post-cooling mechanical responses of geopolymer mortars. However, their effects require separate assessment, particularly regarding the trade-off between ambient mechanical properties and post-heating performance. This study investigated high-calcium fly ash-based geopolymer mortars incorporating recycled brick–tile, ceramic, and hybrid brick–tile/ceramic fine aggregates, together with a separate PP-fiber series containing 0.25%, 0.50%, and 0.75% fiber by fly-ash mass. Flexural and compressive strengths were measured at 3, 7, and 28 days, and 28-day specimens were exposed to 500 and 750 °C. Residual mechanical properties were evaluated after cooling, while SEM-EDS was used to examine thermally induced microstructural and local compositional changes. Replacing limestone with single recycled aggregates reduced ambient strength, whereas the hybrid mixture partly recovered this loss, reaching 19.37 MPa in compression and 5.41 MPa in flexure at 28 days. The 0.75% PP mixture achieved the highest ambient flexural strength (9.78 MPa), 26.0% above the control, although all fiber-reinforced mixtures showed lower compressive strength. Thermal exposure changed the relative ranking of the mixtures: at 500 °C, ceramic and hybrid mixtures increased compressive strength by 94.5% and 65.7%, respectively, while at 750 °C the brick–tile mixture reached 34.91 MPa. The results demonstrate that mixtures with lower ambient strength can exhibit favorable residual performance after severe thermal exposure, highlighting the importance of jointly evaluating recycled aggregate type and PP-fiber dosage for geopolymer mortars intended for thermally demanding conditions.