李增强1,王海龙1,周月霞2,张珍杰2,辜振睿1,程福星2
温控材料对MgO膨胀剂性能影响及其作用机理分析
李增强1,王海龙1,周月霞2,张珍杰2,辜振睿1,程福星2
摘 要:研究了不同温控材料(WK)掺量(0、0.3%、0.4%、0.5%)对掺MgO膨胀剂的水泥净浆水化热特性、砂浆限制膨胀率及抗压强度的影响,并分析了材料的温度敏感性及WK对MgO膨胀剂的影响机理。结果表明:掺WK后,相较于单掺MgO膨胀剂,水泥净浆水化放热得到抑制,但随着MgO膨胀剂掺量的增加,这种抑制作用受到一定程度的削弱;当入模温度为20 ℃和30 ℃时,M-MgO复掺0.4%的WK对水泥净浆水化热温度的抑温率分别为35.6%和48.1%;在20 ℃和60 ℃养护条件下,M-MgO复掺0.4%的WK,相较于单掺M-MgO,砂浆的120 d限制膨胀率分别增长了0.014%和0.028%;WK的掺入会降低砂浆的早期强度,且随掺量的增大,强度损失越明显,但对后期强度无不利影响;WK对MgO膨胀剂水化有一定的激发效果,通过改变MgO膨胀剂的水化历程,影响水化产物的生成速率,进而改变了结构的密实度。
Abstract: The effects of different temperature controlled material(WK) content(0, 0.3%, 0.4%, 0.5%) on the hydration heat characteristics of MgO-doped expansion agent cement paste, limited expansion rate of mortar and mortar compressive strength were studied, and the temperature sensitivity of materials and the influence mechanism of WK on MgO expansion agent were analyzed. The results show that the hydration heat release of cement paste is inhibited by adding WK compared with the single addition of MgO expansion agent, but the inhibition effect is weakened with the increase of MgO expansion agent content. When the molding temperature is 20 ℃ and 30 ℃, the temperature inhibition rates of M-MgO combined with 0.4% WK on the hydration heat temperature of cement paste are 35.6% and 48.1%, respectively. Under the curing conditions of 20 ℃ and 60 ℃, M-MgO mixed with 0.4% WK increases the limited expansion rate of mortar by 0.014% and 0.028% after 120 d compared with the single addition of M-MgO, respectively. The addition of WK can reduce the early strength of mortar, and the strength loss is more obvious with the increase of mixing amount, but it has no adverse effect on the later strength. WK has a certain excitation effect on the hydration of MgO expansion agent, and by changing the hydration process of MgO expansion agent, it affects the generation rate of hydration products, thereby changing the compactness of the structure.
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