Van Belleghem Bjorn, Van den Heede Philip, Van Tittelboom Kim, De Belie Nele
Magnel Laboratory for Concrete Research, Department of Structural Engineering, Faculty of Engineering and Architecture, Ghent University, Tech Lane Ghent Science Park, Campus A, Technologiepark Zwijnaarde 904, B-9052 Ghent, Belgium.
Strategic Initiative Materials (SIM vzw), Project ISHECO within the Program "SHE", Tech Lane Ghent Science Park, Campus A, Technologiepark Zwijnaarde 935, B-9052 Ghent, Belgium.
Materials (Basel). 2016 Dec 23;10(1):5. doi: 10.3390/ma10010005.
Formation of cracks impairs the durability of concrete elements. Corrosion inducing substances, such as chlorides, can enter the matrix through these cracks and cause steel reinforcement corrosion and concrete degradation. Self-repair of concrete cracks is an innovative technique which has been studied extensively during the past decade and which may help to increase the sustainability of concrete. However, the experiments conducted until now did not allow for an assessment of the service life extension possible with self-healing concrete in comparison with traditional (cracked) concrete. In this research, a service life prediction of self-healing concrete was done based on input from chloride diffusion tests. Self-healing of cracks with encapsulated polyurethane precursor formed a partial barrier against immediate ingress of chlorides through the cracks. Application of self-healing concrete was able to reduce the chloride concentration in a cracked zone by 75% or more. As a result, service life of steel reinforced self-healing concrete slabs in marine environments could amount to 60-94 years as opposed to only seven years for ordinary (cracked) concrete. Subsequent life cycle assessment calculations indicated important environmental benefits (56%-75%) for the ten CML-IA (Center of Environmental Science of Leiden University-Impact Assessment) baseline impact indicators which are mainly induced by the achievable service life extension.
裂缝的形成会损害混凝土构件的耐久性。诸如氯化物等诱发腐蚀的物质可通过这些裂缝进入基体，导致钢筋腐蚀和混凝土劣化。混凝土裂缝的自修复是一项创新技术，在过去十年中得到了广泛研究，它可能有助于提高混凝土的可持续性。然而，到目前为止所进行的实验无法评估与传统（有裂缝的）混凝土相比，自愈合混凝土可能延长的使用寿命。在本研究中，基于氯化物扩散试验的输入数据对自愈合混凝土的使用寿命进行了预测。用封装的聚氨酯前体对裂缝进行自修复形成了一道部分屏障，可防止氯化物立即通过裂缝进入。自愈合混凝土的应用能够使裂缝区域的氯化物浓度降低75%或更多。结果，在海洋环境中，钢筋自愈合混凝土板的使用寿命可达60 - 94年，而普通（有裂缝的）混凝土仅为7年。随后的生命周期评估计算表明，对于十个CML - IA（莱顿大学环境科学中心 - 影响评估）基线影响指标具有重要的环境效益（56% - 75%），这主要是由可实现的使用寿命延长所导致的。
