煅烧高岭土尾矿掺合料砂浆的抗硫酸盐侵蚀性能研究

Study on Sulfate Resistance Performance of Mortar with Calcined Kaolin Tailings Admixture

研究了煅烧高岭土尾矿作辅助胶凝材料(单掺以及与石灰石复掺)时,其掺量对水泥胶砂强度及抗硫酸盐性能的影响,并通过XRD对其水化产物、抗硫酸盐侵蚀机理进行了分析。结果表明,无论是单掺煅烧尾矿还是与石灰石复掺,其抗压强度都随着掺量的上升而下降,但与石灰石粉复掺有利于水泥砂浆的早期强度。水泥砂浆中掺煅烧高岭土尾矿能显著提高其抗硫酸盐性能,且抗硫酸盐系数随煅烧高岭土尾矿掺量的增加而提高;单掺煅烧高岭土尾矿的抗硫酸盐性能优于与石灰石复掺的样品。微观分析结果表明,随着煅烧高岭土尾矿掺量增加,火山灰反应使硬化水泥浆体中氢氧化钙含量降低,形成了更多的水化产物和较为致密的结构。

The influence of the substitute ratio of calcined kaolin tailing or mixed with limestone as auxiliary cementitious material to the strength and sulfate resistance of cement mortar was studied.The hydration products and sulfate resistance mechanism were analyzed by XRD.The results show that the compressive strength of the mortar decreases with the increase of the content of calcined tailings or mixed with limestone,but the early strength of the mortar is better with the addition of the limestone powder.Calcined kaolin tailing can significantly improve the sulphate resistance of cement mortar,and its sulphate resistance coefficient increases with the increase of the its substitution.The sulphate resistance of the mortar blending with calcined kaolin tailing is better than that of mixed with limestone.The results of micro analysis show that with the increase of the content of Calcined Kaolin Tailings,the content of calcium hydroxide in the hardened cement paste is reduced by the pozzolanic reaction,resulting in more hydration products and denser structure.