Yazarlar
Kezban Ozlutas
Yayın tarihi
2015/4
Enstitü
University of Dundee
Açıklama
Increased demand for lightweight materials to reduce the dead loads of structures has stimulated the need for even lighter foamed concrete (FC). However, ultra-lightweight FCs (ULFCs)(plastic density< 600 kg/m³) were reported to often result in unstable mixes, with some of them (plastic densities below 400 kg/m³) even leading to failures due to segregation. There is, in fact, insufficient information available on ultra-lightweight FCs. Therefore, this study aimed to examine ULFCs focusing on stability, microstructure, contribution to sustainable construction, insulation performance as well as fresh and hardened properties.
The study provided an empirical insight into the stability mechanism of FC by considering a series of hypotheses leading to a proposed solution for stability issues. Accordingly, the study described use of calcium sulfoaluminate (CSA) cement, in combination with Portland cement (PC), in order to reduce the setting times of the mixes to achieve stable ULFCs. Plastic densities ranging from 150 to 300 kg/m³ with combinations of PC with 5% and 10% CSA by mass and w/c ratio of 0.50 were utilised. To support the hypotheses and the proposed solution, stability, initial setting and collapse time as well as bubble and microstructure analyses were carried out on the mixes under consideration. The data suggested that FCs with densities down to 150 kg/m³ can be produced successfully, provided that the initial setting time of the base mix does not exceed 20-25 minutes. Furthermore, the data proved the linkage between the setting time, bubble size and stability such that shorter setting times resulted in smaller bubble sizes hence stable …
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