Shakir Almashhadani , Faiq Al-Zwainy and Mohammed Aldikheeli
Abstract
The current research presents an experimental investigation on the influence of cooling regime on the residual mechanical properties and cracking development of fiber reinforced eco-Friendly Self-Consolidating Concrete (FSCC). Seven Sustainable (FSCC) mixes containing high volume class F fly ash and locally available Cement Kiln Dust (CKD) were subjected to four high temperature degrees (200, 400, 600 and 800°C) for 2 h. After that, the specimens were cooled either slowly (air cooling) or quickly (water spraying cooling) and the residual compressive strength, flexural strength, modulus of elasticity, Ultrasonic Pulse Velocity (UPV), mass loss and both color change and cracks development were determined. The results indicated, for both cooling techniques, that FSCC with high volume class F fly ash showed best residual mechanical properties when exposed to elevated temperature compared to other mixes. At 800°C, the relative residual compressive strength, flexural strength and modulus of elasticity were 62, 65, 71, 51, 53, 60, 29, 32, 33, 24, 26, 28, 31, 32, 34, 23, 24, 25% for 40, 50, 60% fly ah mixes air and water cooled, respectively. Visual examination of the specimens showed that the color is gradually lightened as the temperature exposure increases and the cracks developed more severely, especially in water cooled pure and cement kiln dust FSCC mixes while in fly ash FSCC mixes smaller network minor surface cracks is observed. At 400°C air cooled fly ash FSCC mixes are classified as good quality mix while other mixes were doubtful based on (UPV). The weight loss is congruent with the residual mechanical properties and the visual inspection of the studied FSCC mixes.
فائق محمد سرحان محمد الزويني | Faiq M. S. Al-Zwainy | 7464