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Title |
The Self-healing and Ageing Effect of OPC-GGBFS Cement in Sea-water and Tap-water
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Authors |
김태완(Tae-Wan Kim) ; 강충현(Choonghyun Kang) |
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DOI |
https://doi.org/10.4334/JKCI.2017.29.1.011 |
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Keywords |
자기치유 ; 해수 ; 초음파 속도 GGBFS ; self-healing ; sea water ; ultrasonic pulse velocity ; brucite |
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Abstract |
The paper presents experimental results of self-healing effects of OPC-GGBFS paste with cracked and uncracked specimens. The self-healing of cracked specimens is processes of crack closing with re-hydration of unhydrated in crack surface. The OPC paste with GGBFS replacement ratios of 0%, 10%, 20% and 30% were prepared having a constant water-binder ratios of 0.5. The OPC-GGBFS paste specimens immersed in tap-water and sea-water. The temperature of tap and sea-water was 5°C, 15°C and 25°C. The cracked specimens after deterioration were immersed for 60 days. The relationship between self-healing effect and age-effect was calculate based upon the experimental results. The self-healing effect was measured in ultrasonic pulse velocity (UPV) before and after loading. When the relative change rate of UPV is increases with the increase in GGBFS replacement ratios. Moreover, the self-healing effect is increased with the temperature of tap-water is increase. But the cracked specimens immersed in sea-water was unclear effects of different temperature. Furemore, most of the healing for OPC-GGBFS specimens immersed in tap-water and sea-water occurred during the first 30 days. The self-healing effect until 30 days is higher than that the age-effect. After 30 days, self-effect and age-effect was largely decreases. SEM/EDS analysis of crack on the surface of the specimens in tap-water were covered with aragonite, and sea-water were covered with brucite.
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