外掺MgO水泥基材料的微观结构研究

Study on microstructure of MgO cement-based materials

为了促进外掺MgO混凝土的推广应用,以压汞法和扫描电镜为检测手段,对压蒸后的外掺MgO水泥基材料的微观结构进行研究。研究结果表明,无论是哪种水泥基材料,掺入适量MgO后试件的孔隙结构均有所改善。但当MgO掺量超过极限掺量后,试件的孔隙结构劣化,微观结构出现裂纹。MgO水泥砂浆试件中掺入粉煤灰后孔隙结构得以优化,微观结构更加致密。粉煤灰的掺入不会改变MgO水泥基材料的膨胀变形规律,MgO掺量超过极限掺量后,结构仍然会因为MgO膨胀过大而破坏。

In order to prompt the application of MgO concrete, the microstructure of MgO cement-based materi- als autoclave-treated has been studied by mercury intrusion porosimetry and scanning electron microscope. The results show that the pore structure of all specimens was improved with adequate MgO content no matter what kind of cement-based materials. However, the pore structure of specimens was deteriorated and the mierostructure emerged cracks when the MgO content exceeds the ultimate content. By using fly ash, the pore structure of MgO cement mortar specimens was optimized and the microstructure became denser. The expansion deformation regularity of MgO cement-based materials was not changed with fly ash. Owing to the over expansion of MgO, the pore structure of specimens was still damaged when the MgO content exceeds the ultimate content.