Study On Resistance To Sulfate Attack On Mortar Containing Mineral Admixture

In the actual engineering applying, the influence factors of the concrete durability is complicated, such as the chemical corrosion and freezing to melt to damage and the alkali-aggregate reaction.In the chemical corrosion aspect, the sulphate attack is an important influence factor, mainly because in actually the sulphate attack environment is widespread, especially in the groundwater and soils more or less existed SO₄^2-.The mineral admixture as a kind of industry waste residue, having already been used in the cement and concrete produce.Now,the slag and the fly ash are the common used mineral admixtures.In this text, according to the formation,live source and the action mechanisms of the slag and the fly ash,we make the mortar fraction with the different W/C,the different G/S,and the different admixture percents,then put them in the saturated sodium sulfate liquor for a long time. By testing the press resistance strength coefficient,the flexural resistance strength coefficient and the weights losing coefficient,then studying the sulphate attack resistance property and attack mechanism of the mortar mixed with admixture,and the main results are as follows:â‘ in three kinds of evaluation methods that this research adopt, the press resistance strength coefficient method and the flexural resistance strength coefficient method are better than the weights losing coefficient method.â‘¡in the different testing period, the sulphate attack resistance property of the mortar mixed with slag is better than the common mortar;The sulphate attack resistance property of mortar mixed with slag when its G/S is 1:3 and 1:4 is better than when its G/S is 1:5;Along with the more content,the sulphate attack resistance property of mortar mixed with slag is better when its G/S is 1:3 and 1:4,but worse when its G/S is 1:5.â‘¢the sulphate attack resistance property of the mortar mixed with fly ash is bad in the earlier period, but good in the latter period. After immersion for 12 months, there were only a small part of samples being eroded and destroyed, the sulphate attack resistance property is better than the mortar mixed with slag.â‘£through scan electronic microscope( SEM) observation, combining the curve of strength and weights, analyze the reaction mechanism of the sulphate attack.