To reduce the dead load of concrete structures, this study developed a high performance lightweight aggregate concrete (HPLAC) by combining the use of ultra high performance cementitious composite (UHPC) and different types of aluminosilicate lightweight aggregates (LWAs). The physicochemical properties of two types of LWAs (i.e. expanded clay and expanded shale) influencing the HPLAC were elaborated and compared. The composition distribution and micromechanical properties in the interfacial regions of paste and LWAs were revealed by elemental mapping and nanoindentation. The results showed that the incorporation of the clay LWAs or shale LWAs in the HPLAC led to similar density and thermal conductivity values, while the use of the shale LWAs induced a lower water absorption and higher strength of HPLAC as compared to the clay LWAs due to the fine pore structure and higher pozzolanic activity of the former. The internal curing effect provided by the pre-wetted shale LWAs was more efficient in enhancing the hydration of binder, and the Al dissolution from the shale LWAs further densified the interfacial bonding to form a dense rim surrounding LWAs, resulting in improved micromechanical properties at the interface. The X-ray CT results indicated that the adoption of UHPC was beneficial to preventing segregation of the LWAs and steel fibers in the HPLAC. By virtue of the physical-chemical interactions of LWAs, the synergetic use of UHPC and pre-wetted shale LWAs was able to produce an HPLAC with high structural efficiency, good thermal insulation, low autogenous shrinkage and permeability.

为了减少混凝土结构的静载，本研究通过结合使用超高性能水泥基复合材料 (UHPC) 和不同类型的铝硅酸盐轻骨料 (LWA)，开发了一种高性能轻骨料混凝土 (HPLAC)。详细阐述并比较了影响HPLAC 的两种LWA（即膨胀粘土和膨胀页岩）的物理化学性质。通过元素映射和纳米压痕揭示了糊剂和 LWA 界面区域的成分分布和微机械特性。结果表明，在 HPLAC 中掺入粘土 LWA 或页岩 LWA 导致相似的密度和热导率值，由于页岩 LWA 的细孔结构和较高的火山灰活性，与粘土 LWA 相比，页岩 LWA 的使用导致 HPLAC 的吸水率更低，强度更高。预润湿的页岩 LWAs 提供的内部固化效果更有效地增强了粘合剂的水化作用，页岩 LWAs 的 Al 溶解进一步致密了界面结合，形成了围绕 LWAs 的致密边缘，从而改善了 LWAs 的微观力学性能。界面。X 射线 CT 结果表明，采用 UHPC 有利于防止 HPLAC 中 LWA 和钢纤维的偏析。凭借 LWAs 的物理-化学相互作用，UHPC 和预湿页岩 LWAs 的协同使用能够产生具有高结构效率、良好隔热、