PURPOSES : The purpose of this study was to suggest a quantitative trend of the daily and seasonal cyclic movement of transverse crackwidth based on measurements in CRCP(Continuously Reinforced Concrete Pavement) within the first year of construction. METHODS : Crack gauges were installed in eight normal cracks, two induced cracks, and two construction joints of newly constructed CRCP. Crack width movements were continuously collected for about a year to investigate the cyclic behavior after construction. The daily and seasonal crack width movements were quantitatively analyzed and compared. RESULTS: Crack width movement in hot weather was relatively less than in cold weather. As a result of frequency analysis of the daily cyclic behavior, it was revealed by measurement that the minimum crack width from 2 p.m. to 4 p.m. was caused by expansion of the concrete; and that the maximum width from 6 a.m. to 8 a.m. was caused by contraction. Average crack width movements were calculated for every month and showed seasonal cyclic behavior. Maximum crack width was measured from December to January. Average crack width was investigated from March to April. Daily crack width movement in relation to concrete temperature was calculated from -0.00017 to -0.03844 mm/℃ and showed gradual decrease in absolute value with time caused by change in the crack spacing. It was found that the relationships between the monthly average crack width and concrete temperature are from -0.004 to -0.012 mm/℃. CONCLUSIONS : Crack-width movement shows a daily and seasonal cyclic behavior. Crack-width measurement in any time or season will have variance caused by daily and seasonal cyclic movement. Variances and trends were obtained in this study based on measurements for various cracks. The long-term behavior of cracks should be surveyed and compared with these measurements to investigate trends of convergence with time, caused by convergence of crack spacing.

시멘트 콘크리트 균열은 수화 반응에 의한 경화수축이 하부 마찰과 같은 구속으로 의해 인장응력을 발생시키고 콘크리트의 인장강도를 초과할 때 발생한다. 이러한 이유로 줄눈 콘크리트 포장은 줄눈 절단을 통해 균열의 위치를 인위적으로 결정하지만 연속철근 콘크리트 포장은 균열을 허용하되 내부 철근을 통해 균열의 폭을 제어하여 포장의 기능을 확보하게 된다. 포장의 균열은 수분이 포장 내부로 침투할 수 있게 하므로 하부 층에 영향을 미치고 철근의 부식을 발생시키며 골재 맞물림에도 영향을 미치기 때문에 설계자는 적정 균열 폭을 얻기 위한 철근의 양을 결정하고 우리나라 고속도로의 경우 일반지역은 0.68∼0.70%, 특수 환경은 0.73∼0.74%를 표준설계 세목으로 제시하고 있다. 균열이 발생한 이후에는 온도에 따라 수축․팽창이 발생하면서 균열 폭의 변화가 발생하며 밤에 대기 온도가 떨어져 콘크리트가 수축하면 균열의 폭은 넓어지고 낮에 대기 온도가 올라가 콘크리트가 팽창하면 균열의 폭은 좁아진다. 본 연구는 연속철근 콘크리트 포장 균열 폭에 대한 정량화된 움직임을 관찰하기 위해 콘크리트에 균열이 발생한 후 균열 게이지를 설치해서 초기 1년 동안 발생한 균열 폭을 계측한 데이터를 분석하였다. 과거 균열 거동은 공용 구간에 짧은 기간 동안 계측하여 얻은 결과를 통해 중간정도 공용기간의 일일 변화에 초점을 두었으나 본 계측은 계절적으로 어떻게 변화하는지를 관찰하는데 중점을 두었다