Artificial-Crack-Behavior Test Evaluation of the Water-Leakage Repair Materials Used for the Repair of Water-Leakage Cracks in Concrete Structures
There are no existing standard test methods at home and abroad that can verify the performance of water leakage repair materials, and it is thus very difficult to perform quality control checks in the field of water leakage repair. This study determined that the key factors that have the greatest impact on the water leakage repair materials are the micro-behaviors of cracks, and proposed an artificial-crack-behavior test method for the performance verification of the repair materials. The performance of the 15 kinds of repair materials that are currently being used in the field of water leakage repair was evaluated by applying the proposed test method. The main aim of such a test method is to determine if there is water leakage by injecting water leakage repair materials into a crack behavior test specimen with an artificial 5-mm crack width, applying a 2.5 mm vertical behavior load at 100 cycles, and applying 0.3 N/mm2 constant water pressure. The test results showed that of the 15 kinds of repair materials, only two effectively sealed the crack and thus stopped the water leakage. The findings of this study confirmed the effectiveness of the proposed artificial-crack-behavior test method and suggest that it can be used as a performance verification method for checking the responsiveness of the repair materials being used in the field of water leakage repair to the repetitive water leakage behaviors that occur in concrete structures. The study findings further suggest that the use of the proposed test method makes it possible to quantify the water leakage repair quality control in the field.
Thermal Stability Test Evaluation of Applying the Artificial-Crack of Water-Leakage Repair Materials Used in the Maintenance of Concrete Structure
콘크리트 구조물은 건축된 이후부터 다양한 열화 환경에 노출 된다. 그 과정에서 반복적이고 지속적인 온도 변화로 인해 수축과 팽창이 반복되면서 콘크리트 구조물에서는 다양한 크기의 균열이 발생난다. 이러한 균열은 콘크리트 구조물의 내구성에 치명적인 문제점을 야기해 사용자로 하여금 불편함을 느끼게 함은 물론 초기 공사비 대비 많은 보수비용이 지출되고 있다. 유지 보수에도 불구하고, 누수로 인한 피해 사례가 사회적 문제 점으로 인식되는 이유는 현재 환경 조건에 따른 콘크리트 구조물 의 온도 변화의 안정화 정도를 판단할 수 있는 규격화된 표준 기준 없이 단순히 재료의 기본 물성에만 의존하여 누수 보수재료를 사 용하고 있으며, 이러한 문제는 반복적인 재 누수로 이어져 유지 보수비용을 증가시키고 있는 실정이다. 이에 본 연구에서는 콘크리트 구조물에 사용되는 누수보수재료 의 온도 변화에 대한 성능을 검증 할 수 있는 품질관리 평가 방법을 제안하고, 이를 이용하여 현재 누수보수 시공에 사용되고 있는 보 수재료의 성능을 검증하여 온도 안정성시험평가의 정량화된 품질 관리를 목표로 하였다. 콘크리트 구조물의 유지보수에 사용되는 누수보수재료의 인공 균열을 이용한 온도 안정성 시험평가 Thermal Stability Test Evaluation of Applying the Artificial-Crack of Water-Leakage Repair Materials Used in the Maintenance of Concrete Structure
SIMILITUDE FOR SHAKING TABLE TESTS ON SOIL-STRUCTURE-FLUID MODEL IN 1g GRAVITATIONAL FIELD
ABSTRACT A similitude is derived for the shaking table tests on saturated soil-structure-fluid model in 1 g gravitational field. The main tool used for deriving the similitude is the basic equations which govern the equilibrium and the mass balance of soil skeleton, pore water, pile and sheet pile structures, and external waters such as sea. In addition to the basic equations, an assumption is made upon the constitutive law of soil; i. e. the stress-strain relation is determined irrespective of the confining pressures if appropriate scaling factors are introduced for the stress and the strain for taking the effect of the confining pressures into account. Applicability of this assumption is examined by using the presently available data under the confining pressures ranging from 0.05 to 1 kgf/cm2 (from 5 to 98 kN/m2) and 0.05 to 4 kgf/cm2 (from 5 to 392 kN/m2). The results indicate that the assumption is applicable within the intermediate strain levels; i. e. the strain levels which are lower than the strains at failure. In consequence, the similitude derived in the present study is applicable to the model tests in which the major concern is directed toward the deformation, rather than the ultimate state of stability, of the soil-structure-fluid system.