Concrete Temperature History and Micropore by using Insulation Gang-Form in -20℃ Cold Weather Conditions

-20℃ 혹한기 조건에서 단열갱폼 사용에 따른 콘크리트 온도이력 및 미세공극 특성

This paper is about a test performed to concrete form work in $-20^{\circ}C$ cold weather conditions on climate change by global warming Furthermore, this paper examines limitations in application insulation gang form and analysis temperature history, strength development and characteristic of micropore of concrete placed in abnormal winter weather. According to the test result, concrete temperature dropped below $0^{\circ}C$ in the case of general gang form 12 hours after concrete placement. However, we could find excellent insulating effect rather than general gang form in the case of insulation gang form because temperature of outer surface and core of concrete has not dropped below $7^{\circ}C$ and highest temperatures was recorded $8{\sim}10^{\circ}C$ within 12 hours despite drastic ambient temperature conditions after concrete placing. In comparison of temperature record of surface portion of insulation gang form and that with or without wales by temperature record of insulation weak point, with wales is not as good as that on surface portion of insulation gang form. The reason for this is thought to be the decline in hydration reaction of concrete due to the decreases of ambient temperature and lack of insulation effect by wale protection made of pvc. As concrete got aged, the number of micropores less than $1{\mu}m$ has increased and it of the large voids has decreased. Also, more small pore were observed in concrete placed with insulation gang form than with general gang form.