The early-age properties and relationships between hydration heat and autogenous shrinkage in high-strength mass concrete of different mixture proportions are investigated through analysis of the history curves of hydration heat and autogenous shrinkage. The hydration temperature and hydration heating velocity (HHV) of the concrete were found to increase with increases in specimen size and decrease when the concrete contained a retarder, fly ash (FA) and ground granulated blast-furnace slag (GGBS). Even in samples of the same mixture proportion, autogenous shrinkage was noted to become greater as the inner temperature increased. The autogenous shrinkage of highstrength mass concrete containing FA and GGBS was lower than that of ordinary Portland cement high-strength mass concrete. The autogenous shrinking velocity of concrete increased as the size of the specimen increased and decreased when the concrete contained a retarder, FA and GGBS. Finally, a close correlation was found between the hydration temperature and autogenous shrinkage at an early age: a higher HHV and a larger HHV-maturity factor led to greater autogenous shrinkage.
This study performed accelerated corrosion tests on reinforced concrete (RC) specimens reinforced with transverse steel bars to evaluate the concrete cracking and rebar strain behaviors caused by rebar corrosion. Seven RC specimens were created with variable compressive strengths, rebar diameters, and concrete cover thicknesses. To mimic in-situ conditions, the accelerated corrosion tests applied a current to the longitudinal bar and transverse bar for different periods of time to create an unbalanced chloride ion distribution. These tests evaluated the amount of rebar corrosion, corrosion cracking properties, and transverse bar strain behavior. The corrosion rate of the transverse bar was faster than that of the longitudinal bar, and cracking first occurred in the concreate around the transverse bar in the specimens with low concrete compressive strength and thin concrete cover. Corrosion cracking and rebar strain were greatly affected by the behavior of the corrosion products that resulted from the pore volume and cracking properties of the cement paste.
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