养护条件对MgO膨胀剂膨胀性能的影响

The Effect of Different Curing Conditions on the Expansive Properties of MgO Expansive Agent

对水养、水养转干养和干湿循环养护条件下不同活性MgO膨胀剂(MEA)膨胀性能及水养条件下不同龄期膨胀净浆微观孔结构进行了研究。结果表明:MEA活性越高,其早期膨胀率增速越大,但后期膨胀率增速越慢;水养转干养条件下,干空膨胀落差与MEA活性成正比;干湿循环养护条件下,高活性MgO的补偿收缩效能高于低活性MgO。掺MEA浆体中大于50 nm孔隙的增加可能是砂浆产生膨胀的原因之一;28~180 d时,MEA主要细化的孔区间为20~200 nm。

The expansion properties of different active MgO expansive agent(MEA)under the conditions of water curing,water curing to dry curing and dry and wet cycle curing and micro pore structure of different age expansive paste under water condition were studied.The results show that the higher the activity of MEA,the higher the early expansion rate,but the slower the later expansion rate.Under the condition of water curing to dry curing,dry air expansion drop is directly proportional to MEA activity.Under the condition of dry and wet cycle curing,the compensation contraction efficiency of high active MgO is higher than that of low active MgO.The addition of MEA promotes the increase of pores larger than 50 nm in the paste,which may be one of the reasons for the expansion of the mortar.At the age of 28 to 180 days,the main refining pores of MEA are between 20 nm and 200 nm.