Akademik Veri Yönetim Sistemi
CONSTRUCTION AND BUILDING MATERIALS, cilt.491, ss.1-20, 2025 (SCI-Expanded)
Self-compacting concrete (SCC) has become increasingly popular due to its beneficial properties, such as reducing labor and construction time, achieving higher quality finish surfaces, and facilitating the construction of heavily congested structural elements. However, the requirement for a greater volume of paste and fine aggregate in the mix design of SCC, compared to ordinary concrete, raises concerns about increased shrinkage. The novelty of this study lies in the use of a low coarse aggregate-to-total aggregate ratio of 0.25, which aims to diminish the beneficial impact of coarse aggregate content on shrinkage performance. This approach seeks to achieve dimensional stability in SCC by incorporating various types and hybrid forms of fiber and allows to investigate their effects on reducing cracks that arise from restraint. In this sense, four fiber types (double- hooked-end steel fiber as macro, short and long straight steel fiber, and PVA synthetic fiber as micro fibers) and their hybridizations (single, binary, ternary, and quaternary) were utilized.Experimental results showed that among the fiber-reinforced SCC mixtures, although all mixtures met the self-compacting criteria, only the binary blend containing 0.8 %macro steel fiber and 0.2 %short micro steel fiber satisfied both the SF3 and VS2/VF2 class limits, while all were classified in PJ1 according to EFNARC. This binary blended sample also showed the highest compressive strength gain, with increases of 24.45 %, 28.89 %, and 20.72 % compared to the control sample at 3, 28, and 90 curing days, respectively. In terms of flexural strength, the ternary blend of 1 %macro steel fiber, 0.8 %long micro steel fiber and 0.5 %PVA demonstrated the greatest enhancement. It showed a 56.8 % increase relative to the control SCC sample, achieving the highest toughness at 101.7 N-m, and displayed significant multiple-cracking behavior among the 90-day samples. Furthermore, under restrained conditions, the quaternary fiber-blended SCC sample achieved the lowest total crack width and shrinkage strain, measuring 149 μ m and 117 με , respectively. In conclusion, in a system with a low ratio of coarse aggregate, these cracks can be effectively controlled by incorporating fibers and adopting a hybrid approach, which not only enhances strength, but also ensures that the fresh properties stay within the SCC standards.