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시험도로 연속철근콘크리트 포장에서의 수평균열에 관한 연구
조병위,김성민 慶熙大學校 大學院 院友會 2005 高凰論集 Vol.37 No.-
콘크리트 슬레브 증간깊이에 발생한 수평균열에 의한 스폴링, 펀치아웃같은 손상들이 연속철근콘크리트 포장(CRCP)에서 관찰되었다. 수평균열의 원인을 밝혀내기 위해서 현장실험과 더불어 수치해석을 수행하였으더 코어를 채취하여 콘크리트 슬래브 내에 수평균열의 분포를 조사하였다. 수평균열의 원인들을 파악하기 위해 설계, 재료 및 환경에 관련된 다양한 변수들을 현장 실험 및 수치해석시 고려하였고 CRCP의 수치해석 모델은 유한요소법을 사용하며 개발하였으며, 이 모델에 의해 소사된 CRCP내의 전단 및 인장응력 분포로 현장실험으로부터 얻은 결과들을 확인하였다. 횡방향 근열부근에서 슬래브 중간깊이에 위치한 철근부근에서 가장 높은 전단 및 인장응력이 발생함을 수치해석 결과를 통해 확인하였다. 수평균열이 할생한 단면과 그렇지 않은 단면의 란성계수와 열팽창계수같은 현장타설 콘크리트의 물성치 및 시공단계에서의 환경 조건들에 대한 평가가 수치해석결과가 타당함을 됫받침해준다. Severe spalling and half-depth punchout failures associated with horizontal cracks at the mid-depth of concrete slabs were observed in continuously reinforced concrete pavement (CRCP). To identify the causes of those horizontal cracks, field observations, laboratory tests, and numerical analyses were conducted. The extent of horizontal cracking in the concrete slab was investigated with coring. Several variables relative to design, material, and environment were considered in the field and laboratory studies to evaluate possible causes of horizontal cracking. Numerical models of CRCP were developed using the finite element discretization and the shear and normal tensile stress distributions in CROP were investigated with the models to verify the results obtained from the field and laboratory studies. Numerical analysis results show that maximum shear and normal tensile stresses develop near the depth of steel bars at transverse cracks. Evaluations of in-situ concrete material properties, such as modulus of elasticity and thermal expansion coefficient, from sections with and without horizontal cracks and environmental conditions during construction all support the results of the numerical analysis.
Cho, Byoung Hooi,Nam, Boo Hyun,Seo, Sangyeon,Kim, Jungil,An, Jinwoo,Youn, Heejung Elsevier 2019 Construction and Building Materials Vol.221 No.-
<P><B>Abstract</B></P> <P>Waterstop is a typically used waterproofing material to prevent water leakage through the joints where consecutive concrete casting is not possible during the construction of underground concrete structures. A conventional waterstop, however, frequently allows for water passage through the interface between a waterstop and concrete under a high water-pressure environment owing to a deep excavation depth and high groundwater table. An alternative solution proposed in this study is to use artificial adhesive bonding between the waterstop and concrete using double-sided adhesive tape to actively prohibit water leakage through joints under a high hydrostatic pressure. The performance of the proposed waterproofing system was experimentally evaluated and compared with the control system (without adhesive). The results indicated that the adhesive bonding type resisted water migration under the pressure head of 30 <I>m</I>, whereas the conventional waterstop could not effectively waterproof even at the pressure head of 10 <I>m</I> in the soundly constructed cementitious composite structures. In addition, the peel strength, which is the bonding strength between the adhesive tape and cementitious composite, was measured to quantify the effect of surface contamination of the waterstop on the interface bonding strength. The adhesive tape on the surface of the waterstop was “contaminated” by either or both sand and bentonite slurry for the peel strength test. The results indicate that the surface contamination of the waterstop does not induce a meaningful reduction in the bonding strength for the tested conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Introducing newly designed waterstop to prevent water leakage at the joints. </LI> <LI> Introducing a testing device to evaluate the waterproofing performance at the joints. </LI> <LI> Providing the waterproofing level of conventional waterstop and the newly designed one. </LI> <LI> Proving the peeling strength between adhesive tape and cementitious composite for different contamination conditions. </LI> </UL> </P>