钙铝类水滑石对混凝土抗盐冻性能的影响

以氯盐为主要成分的除冰盐会导致混凝土发生盐冻破坏,而钙铝类水滑石(CAHL)可以对氯离子进行吸附固化。为研究CAHL对混凝土抗盐冻性能的影响,在C30混凝土中分别掺加胶凝材料质量0%、0.5%、1.0%、1.5%、2.0%的CAHL,测试不同CAHL含量对混凝土抗压强度、电通量、盐冻剥落质量、自由氯离子浓度的影响。结果表明:当CAHL掺量≤1.5%时,随着掺量的增加,混凝土的抗压强度逐渐增大,而电通量逐渐降低,说明合适的CAHL掺量可以提高混凝土的致密性;随CAHL掺量的增加,Friedel's盐的衍射峰逐渐增强,说明CAHL可以较好地固化氯离子;CAHL通过提高混凝土致密性和固化氯离子有效降低了盐冻条件下混凝土中的自由氯离子含量;与空白样相比,CAHL掺量为1.5%时的混凝土经28次单面盐冻剥落后质量损失下降22.9%。

Influence of Calcium-Aluminum Hydrotalcite on Salt-Frost Resistance of Concrete

Deicing salt with chlorine salt as main component can cause salt-frost damage to concrete, while Ca-Al hydrotalcite (CAHL) can adsorb and solidify chloride ion. In order to study the influence of CAHL on the salt-frost resistance of concrete, CAHL with the mass fraction of 0%, 0.5%, 1.0%, 1.5% and 2.0% of cementing material was added into C30 concrete, and the influence of different CAHL content on compressive strength, electric flux, salt-frost spalling mass and free chloride ion concentration of concrete was tested. The results show that when the content of CAHL is ≤1.5%, the compressive strength of concrete increases gradually with the increase of CAHL content, while the electric flux decreases gradually, indicating that CAHL can improve the compactness of concrete better under the appropriate content of CAHL. The diffraction peak of Friedel's salt increases gradually with the increase of CAHL content, indicating that CAHL can solidify chloride ion well. By improving the compactness of concrete and solidifying chloride ion, the content of free chloride ion in concrete under salt-frost condition is effectively reduced after adding CAHL. Compared with the blank sample, the mass loss of concrete with CAHL content of 1.5% decreases by 22.9% after 28 times single-sided salt-frost spalling.