新型复合MgO膨胀材料的膨胀效果

Effect of compound MgO expansive material

研究掺加不同量复合MgO的胶砂试件,在不同水化龄期的力学性能、膨胀性能以及在20、50、80℃水中养护,膨胀率的变化过程和趋势.结果表明:随着MgO掺量的增加,膨胀率相应增加,但强度降低,当掺量在6%～8%时,试件的膨胀量与强度可达到较好的平衡;随着水化温度的升高,相同龄期下水泥浆体膨胀率增大,且7～28d龄期内增加的速率比后期的快,但随着龄期的增加,高温养护时的膨胀速率又逐渐小于低温养护的膨胀速率.

The mechanical and expansion properties of mortar mixed with varied amount of compound MgO were investigated at different hydration ages, and the trend of expansion ratio changes occurred in water cure at 20, 50, and 80 ℃ were also explored. Results showed that with the amount increase of MgO mixture, the expansion ratio increased correspondingly while strength decreased. When the mixture ratio ranges were 6%-8% , the expansion and strength of the specimen were in a better balance. However, with the increase of the water temperature, the expansion ratio of the cement paste at same age increased and the increasing speed during 7-28 d was higher than that at the later age. As the hydration age grew, the expansion rate on high-temperature cure gradually decreased and became lower than that on the low-temperature cure.