碳化和加热改性石材微粉对水泥浆体性能影响试验

为提高石材制品生产过程中产生的废弃微粉的再生利用率,通过CO₂碳化和加热预处理,探讨花岗岩石材微粉替代水泥制备水泥基浆体的改性方法。以石材微粉替代率(0%、10%、20%、30%)、石材微粉粒径(2组)、碳化时长(0、24 h)、加热温度(室温、400 ℃、600 ℃)为试验变量,并考虑7 d和28 d龄期的影响,开展了改性再生微粉水泥基浆体流动性和抗压性能的试验研究,分析了各变量对其流动性、抗压强度和破坏模式的影响规律。在此基础上,结合X射线衍射(XRD)测试,揭示石材微粉的改性机理。结果表明:石材微粉的掺入会造成水泥浆体强度的明显下降; 加热改性在一定程度上可以减少石材微粉对水泥浆体的负面作用,其中400 ℃加热改性的效果最佳; 碳化改性该类石材微粉对水泥基浆体的增强效果不佳; 改性前后的石材微粉掺入均不会对水泥浆体的流动性产生明显影响。

Experiment on Effects of Carbonization and Heating Modification of Stone Micro Powder on Performance of Cement Paste

In order to improve the recycling rate of waste micro powder produced in the production of stone products, through CO₂ carbonization and heating pretreatment, the modification methods of using the granite micro powder instead of cement to prepare cement-based paste were studied. Taking stone powder content(0%, 10%, 20%, 30%), stone powder particle size(2 groups), carbonization time(0, 24 h), heating temperature(room temperature, 400 ℃, 600 ℃)as the experimental variables, as well as considering the influence of the curing age of 7 d and 28 d,the experimental study on the fluidity and compressive properties of modified recycled micro powder cement-based pastes was carried out, and the effect laws of various variables on the fluidity, compressive strength and failure mode were analyzed. On the basis, the modification mechanism of stone powder was revealed by X-ray diffraction(XRD)test. The results show that the compressive strength of cement paste decreases obviously with the incorporation of stone micro powder, while the heat modification can reduce the negative effect of stone micro powder on the cement paste to a certain extent, and the optimal heat temperature is 400 ℃. Carbonization modification of stone micro powder has no obvious enhancement effect on the compressive of cement paste. The fluidity of cement paste will not be affected by the incorporation of stone powder before and after modification.