泡沫混凝土结构粉化表征及其分析

Measuring and Analysing Techniques of Structural Pulverization for Foam Concrete

采用铅笔硬度法对泡沫混凝土粉化程度进行了表征,并利用水分蒸发率、SEM、DTG/TG等方法分析了产生粉化的原因。结果表明,泡沫混凝土的铅笔硬度值小于6B时,表明其已产生粉化;低密度泡沫混凝土(小于500kg/m3)容易产生粉化;泡沫混凝土密度越小,早期水分蒸发率越大,24h水分蒸发率超过40%以上时,产生粉化,水分早期快速蒸发是造成泡沫混凝土粉化的原因。泡沫混凝土早期失水使结构疏松,导致CO2更容易侵入而产生碳化,通过分析硬化浆体的CaCO3含量可以分析泡沫混凝土的粉化程度。

In order to research the pulverization of the foamed concrete,scanning electron microscopy（SEM）,differential thermal gravity/thermal gravity（DTG/TG）as well as the evaporation rate of water was employed.The experimental results showed that the structural pulverization for foam concrete could occur when the pencil hardness value is less than6 B,and the low density foamed concrete（less than 500kg/m3）is easy to produce structural pulverization.However,the main reasons that cause the pulverization of the foamed concrete are the low density and the high early water evaporation rate.The pulverization could occur when the water evaporation rate was over 40%in 24 hours.As a result,the water loss of the foamed concrete at the early stage cause the loose structure so that CO2 is easier to invade.CaCO3 content in hardened cement paste can confirm the pulverization degree of the foamed concrete.