Van Mullem Tim, Anglani Giovanni, Dudek Marta, Vanoutrive Hanne, Bumanis Girts, Litina Chrysoula, Kwiecień Arkadiusz, Al-Tabbaa Abir, Bajare Diana, Stryszewska Teresa, Caspeele Robby, Van Tittelboom Kim, Jean-Marc Tulliani, Gruyaert Elke, Antonaci Paola, De Belie Nele
Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium.
Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Turin, Italy.
Sci Technol Adv Mater. 2020 Sep 22;21(1):661-682. doi: 10.1080/14686996.2020.1814117.
Development and commercialization of self-healing concrete is hampered due to a lack of standardized test methods. Six inter-laboratory testing programs are being executed by the EU COST action SARCOS, each focusing on test methods for a specific self-healing technique. This paper reports on the comparison of tests for mortar and concrete specimens with polyurethane encapsulated in glass macrocapsules. First, the pre-cracking method was analysed: mortar specimens were cracked in a three-point bending test followed by an active crack width control technique to restrain the crack width up to a predefined value, while the concrete specimens were cracked in a three-point bending setup with a displacement-controlled loading system. Microscopic measurements showed that with the application of the active control technique almost all crack widths were within a narrow predefined range. Conversely, for the concrete specimens the variation on the crack width was higher. After pre-cracking, the self-healing effect was characterized via durability tests: the mortar specimens were tested in a water permeability test and the spread of the healing agent on the crack surfaces was determined, while the concrete specimens were subjected to two capillary water absorption tests, executed with a different type of waterproofing applied on the zone around the crack. The quality of the waterproofing was found to be important, as different results were obtained in each absorption test. For the permeability test, 4 out of 6 labs obtained a comparable flow rate for the reference specimens, yet all 6 labs obtained comparable sealing efficiencies, highlighting the potential for further standardization.
由于缺乏标准化测试方法，自愈合混凝土的开发和商业化受到阻碍。欧盟COST行动SARCOS正在执行六个实验室间测试项目，每个项目都专注于特定自愈合技术的测试方法。本文报告了对玻璃大胶囊中封装聚氨酯的砂浆和混凝土试件测试的比较。首先，分析了预开裂方法：砂浆试件在三点弯曲试验中开裂，随后采用主动裂缝宽度控制技术将裂缝宽度限制在预定义值以内，而混凝土试件在采用位移控制加载系统的三点弯曲装置中开裂。微观测量表明，通过应用主动控制技术，几乎所有裂缝宽度都在狭窄的预定义范围内。相反，混凝土试件的裂缝宽度变化较大。预开裂后，通过耐久性试验表征自愈合效果：砂浆试件进行了水渗透性试验，并测定了愈合剂在裂缝表面的扩散情况，而混凝土试件进行了两次毛细吸水试验，在裂缝周围区域采用了不同类型的防水处理。发现防水质量很重要，因为每次吸水试验都得到了不同的结果。对于渗透性试验，6个实验室中有4个获得了参考试件可比的流速，但所有6个实验室都获得了可比的密封效率，突出了进一步标准化的潜力。
