Expansions and Damage Processes Of Concrete Due to Coupled Alkali Silica Reactions and Freeze-Thaw Cycles
This study investigates the process of expansions and deteriorations of concrete damaged by the coupled action of alkali silica reactions (ASR) and freeze-thaw cycles (FTC).The authors have previously conducted numerical simulations and showed that the sequence of ASR and FTC can affect the total expansion and the mechanical properties of concrete after their combined actions.It was also suggested that the ASR gel that migrates into the cement hydrate matrices can impair the ability of entrained air in concrete to resist FTC damage.In this study, experiments were conducted using the combination of ASR and FTC actions with different sequences to verify the previous numerical results and understand the expansion and damage process in the combined deteriorations.The rate of expansion due to ASR and FTC actions was measured using prism specimens of different water-to-cement ratios and air contents.It was observed that the preceding ASR acceleration process increased the rate of subsequent expansions due to the FTC.Even if the specimens have sufficient entrained air to prevent expansion by the single FTC action, they can expand under the combination of ASR and FTC.It was confirmed that ASR can decrease the ability of entrained air to resist FTC damage.On the other hand, minimal differences were observed between the ASR expansion after the FTC process and the single ASR expansion.The preceding FTC expansion had minimal effect on the subsequent rate of ASR expansion.The mechanical properties of the cylindrical specimens were investigated.The compressive strengths and the relative dynamic elastic modulus were measured, and it was found that the decrease in the compressive strength due to FTC can be partially restored by the subsequent ASR.The measured relative dynamic elastic modulus also increased during this restoration process, which indicates that the continuity of the material was recovered.The ASR gel migrates into the damaged or cracked part due to FTC, which could have a positive effect on the mechanical properties.
Combined deterioration Alkali silica reaction Freeze-thaw cycles Expansion Mechanical properties
Izuru Segawa Yuya Takahashi Fuyuan Gong Koichi Maekawa
The University of Tokyo, Tokyo, Japan Yokohama National University, Kanagawa, Japan
国际会议
福州
英文
649-658
2018-11-04（万方平台首次上网日期，不代表论文的发表时间）