关键词: 菱镁矿尾渣;MgO膨胀剂;限制膨胀率;活性;膨胀特性

Abstract: In order to explore the probability of the application of MgO-based expansive agents(MEA) produced by magnesite tailings,the activity of MEA and the one-dimension limited expansion of mortars mixed with MEA cured in water at different temperatures has been separately investigated.The results show that different activity MEA can be produced by magnesite tailings calcined at high temperature,and the higher the calcination temperature, the lower the activity.Different expansion characteristics is presented at different temperature water.Correspondingly, the increase of curing temperature exerts a significant impact on the mortars with lower activity MEA.Comparing with the MEA calcined by magnesite,the active components in the MEA calcined by magnesite tailing is relatively lower, as a result,the mortars with the same dosage of MEA perform a poor expansion characteristic.Therefore, in the practical application,the advisable dosage of MEA calcined by magnesite tailing should be properly raised,in order to effectively compensate the shrinkage of concrete.

Key words: magnesite tailing;MgO-based expansive agent;restrained expansion;activity;expansion characteristic