再生复合微粉对水泥胶砂强度的影响和机理研究

Study on the influence and mechanism of recycled composite powder on the strength of cement mortar

以粉煤灰存在下水泥胶砂强度为基准,分别开展再生砖粉、再生混凝土粉不同比例替代部分水泥、粉煤灰时,胶砂在不同龄期下的抗压、抗折强度变化规律,通过SEM和XRD分析强度形成机理。结果表明,再生砖粉和混凝土粉以质量比3∶2复配替代15%水泥时胶砂3 d抗折强度是基准试件的2.62倍;上述复配比下,随复配替代粉煤灰掺量的增加其强度为先提高后降低,掺量为35%时胶砂抗压、抗折强度分别为基准试件的1.56倍、1.51倍;砖混再生微粉可促进水泥水化,提高胶砂密实度,在水化后期可发挥火山灰效应降低水化反应中产生的CH含量。

In this paper,based on the strength of cement fly ash mortar,the compressive and flexural strength of mortar at different ages under different proportions and contents of recycled brick and concrete powder,and the strength formation mechanism is revealed by SEM and XRD. The results show that the recycled brick powder and concrete powder are compounded with the mass ratio of 3∶2 to replace part of cement,the early strength of mortar is 2.62 times higher than that of the reference specimen;Under the condition of maintaining the above compound mass ratio,the strength increases first and then decreases with the increase of the content of compound alternative fly ash. When the content is 35%,the compressive strength of mortar is 1.56 times that of the reference specimen and the flexural strength is 1.51 times. Recycled brick-concrete brick-concrete micro-powder can promote the cement hydration process and improve the compactness of mortar. Recycled brick-concrete micro-powder can play the pozzolanic effect in the later stage of cement hydration and reduce the CH content produced in the process of cement hydration reaction.