掺MgO超细水泥的膨胀性能及其水化程度

Expansion property of super-fine cement paste added MgO expansive agent and hydration degree of MgO

在超细水泥中掺不同活性的MgO膨胀剂(MEA),研究MEA对超细水泥浆体和掺加超细粉煤灰水泥浆体膨胀性能的影响规律,并采用差热-热重同步热分析仪对MgO的水化程度进行表征。结果表明:MEA能很好地补偿超细水泥浆体的收缩,可作为补偿超细水泥收缩的新型膨胀剂;高活性MEA早期水化程度较大,掺高活性MEA水泥浆体的早期膨胀较大,后期膨胀增长趋势较小;低活性MEA早期水化程度低于高活性MEA,掺低活性MEA水泥浆体的早期膨胀较小,但后期膨胀趋势较大;MEA的掺量越大,水泥浆体的膨胀率越大;掺加超细粉煤灰抑制了掺加MEA水泥浆体的膨胀,但没有明显降低MgO的水化程度。

The effects of MgO-bearing expansive agent（MEA） with different activities on expansion property of super-fine cement grouts were investigated.The hydration degree of MgO-bearing expansive agent was analyzed by thermogravimetric-differential thermogravimetric analyzer.Results showed that MEA could compensate the shrink of super-fine cement paste in hard stage commendably.MEA with higher activity caused a larger early expansion and a smaller final expansion,while MEA with lower activity caused a smaller early expansion and a larger final expansion.With the admixture amounts of MEA increasing,the expansion of cement pastes increased.Replacing super-fine cement with super-fine fly ash would restrain the expansion of cement pastes containing MEA.