Influence of Benzenediols—Pyrocatechol and Resorcinol—On the Resistance of Portland Cement Mortars with Aluminum Sulfate to Sulfate Attack

摘要

The effect of benzene-1,2-diol (pyrocatechol) and benzene-1,3-diol (resorcinol) on the development of sulfate attack in Portland cement mortars containing alkali-free setting accelerator (aluminum sulfate) was studied. It has been found that these compounds (especially pyrocatechol—due to its ability to form chelate complexes with aluminum ions) restrain destructive deformations of Portland cement mortars with aluminum sulfate admixture when under test conditions a constant supply of sulfate ions from external source is provided. According to 27Al-MAS NMR data, pyrocatechol does not influence the amount of ettringite formed in Portland cement paste during its store in sodium sulfate solution. Presumably, in presence of benzenediols, in cement mortars with aluminum sulfate admixture the formation of ettringite crystals with a less pronounced destructive effect takes place.