机场拦阻系统泡沫混凝土海水侵蚀性能劣化规律

为评价工程材料拦阻系统(EMAS)在海岛机场的适应性，研究了拦阻系统中泡沫混凝土在高温、高湿和高盐环境中的性能劣化规律；研制了可自动控温、鼓风与补水的全(半)浸泡一体试验装置，分别研究了泡沫混凝土浸泡在30 ℃清水、30 ℃与60 ℃模拟海水中吸水率、变形、压溃强度与半溃缩能等宏观性能的衰变规律；借助X射线断层扫描技术获取了泡沫混凝土的微结构信息，并利用X射线衍射分析技术表征了泡沫混凝土受溶液侵蚀后物相种类与含量的变化。研究结果表明:泡沫混凝土耐海水侵蚀性能较差，在30 ℃清水中浸泡90 d后，其压溃强度降低了11.5%，而浸泡在30 ℃与60 ℃模拟海水中，其压溃强度分别降低了19.9%与52.1%；全浸泡在30 ℃清水与30 ℃模拟海水中时，泡沫混凝土的吸水率性线增大，90 d时约为280%；模拟海水温度升高至60 ℃时，泡沫混凝土浸泡10 d后的吸水率快速增大并稳定在350%左右；泡沫混凝土内部孔隙率为70%，平均孔径为2.0 mm，二维贯穿深度约为8.4 mm，导致溶液极易侵入泡沫混凝土；泡沫混凝土中孔径较大，盐水很难在毛细作用下向上传输，表面未出现盐结晶现象，数次吸水膨胀与风吹干燥收缩循环致使泡沫混凝土表面粉化严重；溶液侵入泡沫混凝土内部，同时引起基体软化、钙溶蚀与离子侵蚀反应，加速了泡沫混凝土的骨架损伤，使其压溃强度降低；工程实践中应尽可能避免海水拍打、礁石撞击单元体，并对单元体及泡沫混凝土做防水处理，以确保EMAS长期稳定有效。 

Performance deterioration law of foam concrete in airport arresting system under seawater corrosion

To evaluate how an engineered material arresting system (EMAS) can be applied in island airports, the performance deterioration laws of foam concrete of the arresting system at high temperature, high humidity and high salinity were investigated. An integrated full (semi) immersion test device was designed, wherein the temperature, air flow, and water volume could be controlled automatically. The deterioration in the macroscopic performance, namely in terms of water absorption, deformation, crushing strength, and half crushing energy, of the foam concrete soaked in freshwater at 30 ℃, simulated seawater at 30 ℃ and 60 ℃, was analyzed separately. The microstructure of foam concrete was examined via X-ray tomography, and the changes in the phase type and content of foam concrete after the solution corrosion were analyzed via X-ray diffraction. Research result demonstrates that the foam concrete cannot satisfactorily resist the seawater corrosion. After the foam concrete is soaked in the freshwater at 30 ℃ for 90 d, the crushing strength decreases by 11.5%. After it is soaked in the simulated seawater at 30 ℃ and 60 ℃, the crushing strength drops by 19.9% and 52.1%, respectively. When it is fully immersed in the freshwater and simulated seawater at 30 ℃, the water absorption increases linearly with time and reaches approximately 280% at 90 d. When the foam concrete is soaked in the simulated seawater at 60 ℃, the water absorption increases rapidly and levels off at approximately 350% after 10 d. The internal porosity and average pore size of foam concrete are 70% and 2.0 mm, respectively. Moreover, the two-dimensional penetration depth is approximately 8.4 mm. Therefore, it is extremely easy for the foam concrete to undergo corrosion. In addition, the relatively large pores render the upward transportation of saltine water under the capillary action difficult, so the salt crystallization is not noted on the surface of foam concrete. The foam concrete is powdered seriously after several cycles of water absorption expansion and wind drying shrinkage. Solutions can reach the interior of the foam concrete, leading to reactions such as matrix softening, calcium dissolution, and ion corrosion, thereby accelerating the damage to the foam concrete's skeleton and lowering its crushing strength. In practical engineering projects, unit bodies of EMASs should not be struck by seawater and reef as far as possible. Furthermore, the unit body and foam concrete should be made waterproof such that the EMAS can last long and function effectively. 3 tabs, 14 figs, 33 refs.