负载纳米TiO2石英砂功能集料-水泥石的界面粘结性能

光催化水泥基材料是先进建筑功能材料的研究热点之一，但传统内掺法制备的TiO₂-水泥基复合材料中TiO₂有效利用率低、经济效益差。针对此问题，采用负载法制备纳米TiO₂功能集料（QST），并将QST集料负载于普通水泥砂浆表面。研究QST集料对水泥砂浆干缩性能的影响，通过拉拔法测试QST集料与水泥石的界面粘结力；采用SEM、EDS、MIP等微观测试方法，研究纳米TiO₂对集料-水泥石界面过渡区水化产物、孔结构的影响。结果表明：与普通石英砂集料相比，表面负载纳米TiO₂的石英砂功能集料可减少水泥砂浆的干缩，提高集料-水泥石的界面粘结力。在QST集料-水泥石的界面过渡区，纳米TiO₂促进了水泥浆体的水化，减少了界面过渡区Ca(OH)₂的富集，细化并改善了界面过渡区的孔结构。

Interfacial bonding characteristics between quartz sand supported nano-TiO2 functional aggregates and cement paste

Photocatalytic cement-based material is one of the research hotspots of advanced building functional materials, but TiO₂ cement-based composites prepared by the traditional internal mixing method have low effective utilization rate of TiO₂ and poor economic benefits. To solve this problem, cement mortar with quartz sand supported TiO₂ (QST) aggregates were prepared and the effects of the QST aggregates on the drying shrinkage performance of the cement mortar was studied. The interfacial bond strength between the QST aggregates and the cement stone was measured using the pull-out strength method. The effects of the nano TiO₂ on the hydration products and pore structure of the interfacial transition zone (ITZ) between the aggregates and the cement stone were studied via SEM, EDS and MIP methods. Compared with ordinary quarz sand aggregates, the QST aggregates can reduce the drying shrinkage of the cement mortar and improve the interfacial adhesion between the aggregates and the cement stone. The nano TiO₂ that was loaded onto the surface of the aggregates promotes the hydration of the cement paste, reduces the enrichment of Ca(OH)₂ in the ITZ, and refines the pore structure of the ITZ between the cement stone and the aggregates.