轻骨料性能对界面区微观结构的影响

Effect of Property of Lightweight Aggregate on Microstructure in the Interfacial Transition Zone

目的研究不同吸水率轻骨料制备的混凝土中骨料-水泥石界面区的微观形貌、水化产物的钙硅质量比、水泥石的显微硬度以及孔结构等性能参数．方法采用扫描电镜（SEM）、X射线能谱分析（EDXA）、显微硬度以及孔结构等试验手段，并与普通骨料混凝土进行对比分析．结果轻骨料-水泥石界面区各项性能均优于普通骨料，轻骨料吸水率越大、表面越粗糙，界面区水泥石结构越致密，孔结构呈细化趋势，低、中、高吸水率轻骨料-水泥石界面区显微硬度较普通骨料分别提高15．8％、79．6％和96．3％，界面增强层厚度为40～60μm，并且，中、高吸水率陶粒混凝土中，距骨料-水泥石界面-10～0μm范围内具有一个明显的内增强层．结论轻骨料性能对界面区水泥石微观结构具有显著影响，中、高吸水率轻骨料可使界面区结构得以改善．

This paper mainly studies the different water absorption of lightweight aggregate concrete prepared aggregate-cement interface zone microstructure, hydration products of calcium silicon ratio, cement microhardness, as well as performance parameters such as pore structure and ordinary aggregate concrete. The Scanning Electron Microscope （ SEM）, Energy Dispersive X-Ray analysis system （ EDX）, Micro-hardness test and pore structure test are applied. Lightweight aggregate-cement interface of the performance is better than the ordinary aggregate, the greater the water absorption of lightweight aggregate is, the more rough the surface is, the denser the cement structure of the interface zone becomes and the pore structure tend to be refined. Compared with ordinary aggregate, the low, middle and high water absorption of lightweight aggregate-cement interface zone microhardness respectively increases by 15.8%, 79.6% and 96. 3% and the thickness of the enhance interface is about 40-60μm. There is an obvious enhanced layer within medium and high water absorption ceramsite concrete and aggregate-cement interfaces are - 10μm-0 μm. The resuits show that the performance of lightweight aggregate has a significant impact on cement paste interface microstructure. The aggregate-cement interface zone microstructure of middle and high water absorption lightweight can be improved.