在多孔材料内部检测发现硫酸盐晶体是证明盐结晶破坏最直接的证据。运用环境扫描电子显微镜、扫描电子显微镜、能谱仪和X射线衍射等微观分析手段,研究了稳定环境和变化环境中,硫酸钠溶液对半浸泡纯水泥净浆和水泥粉煤灰净浆的破坏作用,结果表明:在破坏的净浆试件中并没有发现硫酸钠晶体,反而发现大量的混凝土硫酸盐化学侵蚀产物(钙矾石和石膏等)晶体,硫酸盐化学侵蚀依然是引起净浆试件破坏的主要原因。
In order to verify whether salt sulfate weathering is a mechanism causing porous materials damage, the trace of sulfate crystal can be identified by means of environmental scanning electron microscopy, scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction as well. In this paper, the effect of Na2SO4 solution on the partially exposed cement paste and fly ash cement paste was investigated. The results showed that the crystals of Na2SO4 did not appear under the constant exposure or fluc- tuated exposure condition, however, there exsit a great amount of ettringite and gypsum as the corrosion products of chemical sulfate attack. It is indicated that the chemical sulfate attack is likely still the degradation mechanism for the paste deterioration.