Microscopic Mechanism Analysis on Frost Resistance of Ordinary Concrete under Ethylene Glycol Type Aircraft De-icer

Abstract

On the basis of freeze-thaw damage theories，the freeze-thraw damage pattern and feature of ordinary Portland concrete (OPC) were studied under the aircraft de-icer with ethylene glycol. The micro-phase compositions of specimens were analyzed by X-ray diffractometer，microstructure was observed by scanning electron microscopy and Micro area element was analyzed by energy dispersion X-ray. The main results were remarked as follows: The frost resistance of concrete under the action of lower concentration of EG was more serious than that of water，while the freezing and thawing damage in higher concentration of ethylene glycol was slightly lower than that of water. The lower concentration of aircraft deicing fluid results in more serious damage to the concrete. The freeze-thaw damage of OPC with low concentration of ethylene glycol was mainly the surface spalling failure，and the mass loss reached the standard of failure firstly. However，when immersed in high concentration of ethylene glycol，the freeze-thaw damage of OPC was that the relative dynamic elastic modulus first came up to the failure stand，which was mainly embodied in severe spalling at the ends. In a whole，the freezing and thawing damage was a physical damage mechanism. No new substances were formed during the freezing and thawing experiment in EG. The hydrated calcium silicate gel and crystal of calcium hydroxide were not changed in cement. The freezing thawing damage mechanism of OPC in EG solution was the same as that in water，which was mainly dominated by the freezing pressure.

Keywords: aircraft deicer,  ordinary concrete,  freeze-thaw damage,  icing pressure,  microscopic analysis