Comparison of in situ properties of wall elements cast using self-consolidating concrete

摘要

An experimental program was undertaken to investigate the homogeneity of in situ properties of wall elements cast with various commercially available self-consolidating concrete (SCC) mixtures. Wall elements measuring 5 m in length, 1.6 m in height, and 0.35 m in width were cast. The SCC mixtures were proportioned with various binders and admixtures and had different levels of slump flow consistency and design compressive strengths. The SCC mixtures exhibited adequate passing ability with L-box blocking ratio higher than 0.70 and filling capacity greater than 80%. All cast walls exhibited homogeneous in situ mechanical properties, regardless of the core location. The coefficient of variation (COV) of in situ compressive strength values ranged from 3 to 6%. Conventional vibrated concrete used to cast a reference wall element led to relatively large spread in in situ rapid chloride-ion permeability values and high COV of spacing factor compared to those of the various SCC wall elements (17% vs. 6-12%). Good correlation was established between surface settlement and top-bar factor of reinforcing bars embedded along the various heights of the 1.6-m high walls. On average, concrete with 0.50% surface settlement was shown to exhibit a maximum top-bar factor of 1.4. The mean top-bar factor values near the top of walls cast with SCC were limited to 1.4, which is considered a low value given the high slump flow of the concrete and the depth of cast elements.