某机场道肩混凝土损伤原因分析

Analysis of Causes for Destruction of an Airport Runway Shoulder

某刚建成1年左右的机场道肩混凝土表面出现了开裂和剥落,为分析道肩混凝土损伤的原因,同时进行了现场和试验室的研究工作.根据现场取回的混凝土芯样的外观检查、岩相分析、孔结构分析、抗渗性试验结果,发现道肩混凝土内部粘结不良,结构疏松,密实性较差.对混凝土芯样和按照道肩混凝土配合比,采用工程所用原材料在试验室中成型的混凝土试件进行抗冻性分析,结果发现,混凝土芯样和试验室试件抗冻性均表观不良.故推断此道肩混凝土由于内部粘结疏松、密实性和抗冻性较差,在北方严酷环境作用下,混凝土发生冻融破坏而产生了膨胀开裂和剥落.

The causes for destruction of many concrete projects are very complex. Cracking and spalling appearing on surface of runway shoulder of an airport built up about one year ago. The main mechanism of deterioration has been explored both in field and in laboratory. By means of appearance inspection, petrographic analysis, pore structure analysis and impermeability testing of concrete cores, it is found that the runway shoulder concrete has poor impermeability with loose structure. Concrete samples were made in laboratory with mix proportion used in construction. Testings of the samples and cores show that frost resistance of the runway shoulder concrete is poor. It is concluded that concrete suffers from cracking and spalling after freeze-thaw cycles under severe environmental condition due to the loose structure and poor impermeability.