Evaluation of Service Life of Silicate Impregnated Concrete

실리케이트 함침제를 사용한 콘크리트의 내구수명 평가

Abstract

Chloride attack, one of the major deterioration phenomena in RC(Reinforced Concrete) structure, causes corrosion of reinforcement, and this leads degradation of serviceability and structural problems. The application of silicate based impregnant to concrete surface are known for excellent constructability and cost-benefit for the maintenance of RC structure. In the work, the compressive strength and resistance of chloride diffusion for concrete were evaluated after improving property of concrete surface through two types of silicate based impregnant. Furthermore, based on the previous research and the result from the work, service life analysis was performed. After impregnating of silicate, strength and resistance of chloride diffusion were remarkably improved, and the service life increase to 159% for silicate A impregnation and 304% for silicate B impregnation, respectively.

콘크리트의 주요 열화 현상 중 하나인 염해는 철근의 부식을 야기하며 이로 인해 철근콘크리트 구조물에 사용성 및 구조성에 문제가 발생한다. 콘크리트 구조물의 유지관리를 위해 표면 함침제를 콘크리트에 적용시키는 방법은 시공성 및 경제성이 우수하다고 알려져 있다. 본 연구에서는 두 가지 종류의 실리케이트 용액을 사용하여 콘크리트의 표면의 공학적 특성을 개선시킨 후 압축강도와 염화물 확산저항성을 평가하였다. 또한, 기존의 연구와 본 실험결과를 기준으로 대상단면의 내구수명 해석을 실시하였다. 실리케이트 함침 후 콘크리트의 강도 및 염화물 확산 저항성은 크게 증가하였으며 내구수명은 실리케이트 A에서는 159%, 실리케이트 B에서는 304%로 크게 평가되었다.

Figure 1. Stable zone with pH variation in silicate solution[12]

Figure 2. Photo for RCPT-ASTM C 1202

Figure 3. Photo for RCPT preparation

Figure 4. Compressive strength variation with silicate impregnation

Figure 5. Passed charge variation with silicate impregnation

Figure 6. Before and after SEM of silicate impregnation (5,000 Times magnification)

Figure 7. Accelerated diffusion coefficient of silicate impregnated concrete

Figure 8. Target structure for chloride ingress simulation

Figure 9. Relationship between log-time and log-diffusion

Figure 10. Chloride content variation with increasing service life

Figure 11. Evaluated service life in concrete with surface impregnation

Table 1. Mix proportions for test

Table 2. Physical properties of aggregate

Table 3. Properties of super plasticizer

Table 4. Components of Silicate based impregnant

Table 5. Criteria of total passed charge[16]

Table 6. Chloride analysis conditions for service life