Effect of Supplementary Cementitious Materials on Hemp FiberReinforced Structural Lightweight Concrete with Pumice Aggregate
ACE2026 - The International Congress on Advances in Civil Engineering, Trabzon, Türkiye, 12 - 13 Ekim 2026, ss.779-786, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Trabzon
- Basıldığı Ülke: Türkiye
- Sayfa Sayıları: ss.779-786
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
Structural lightweight aggregate concrete (LWAC) offers advantages to reduce structural dead loads; however, like conventional concrete, its inherently brittle behavior requires reinforcement to enhance flexural performance. The use of natural fibers as a renewable resource may improve the mechanical response of LWAC. This potential benefit, however, should be evaluated by taking their durability in the alkaline cementitious environment into consideration. This study investigates the mechanical performance of hemp fiber reinforced structural lightweight concrete (HSLWC) incorporating volcanic pumice aggregate (VPA, 2-10 mm) and supplementary cementitious materials (SCMs). Metakaolin (MK), Class F fly ash (FA), and their combination constituted 20% of the total binder content. Binder content was 350 kg/m³ for the reference (C) and MK mixtures, and 400 kg/m³ for the FA and MK+FA mixtures, with a constant water-to-binder ratio (w/b) of 0.40. The 100% cement reference was fiber-free, all SCM-containing mixtures contained 1% hemp fiber. Compressive strength was determined at 7 and 28 days, water absorption was measured, and flexural strengths were assessed through three-point bending tests. In addition, 28-day prism specimens were immersed in water at 50 ± 2 °C for seven days to evaluate the effect of accelerated aging. The MK mixture achieved the highest compressive strength and binder efficiency with a total binder content of 350 kg/m³. At a binder content of 400 kg/m³, MK+FA produced higher performance than FA. Water absorption remained within a narrow range of 3.1–4.1% despite the use of 50% VPA by volume. Maximum flexural load increased after accelerated aging, and MK+FA series maintained the highest load before and after aging. Overall, the combined MK+FA system yielded the best balance among compressive strength, flexural performance, water absorption, and sorptivity.