Preparation And Properties Of Thermal Insulation Material For Aqueduct

South-to-North Water Transfers is one of the largest scale hydraulic engineering infrastructure construction in China. The project is to resolve the critical shortage of water resource in north China, which refers to the sustainable development of Chinese economy and society. The large-scale aqueduct is one of the most important parts in the project. The safety of long-term operation of the aqueduct has directly relationship to the normal running of the whole project. But the temperature stress is a bad factor which would possibly be able to damage the concrete of the aqueduct. The excessive temperature stress would cause cracking in the aqueduct, which would bring negative effects to the integrity and durability to the structure of the aqueduct. Obviously, there is practical significance to eliminate or decrease the temperature stress in order to keep the aqueduct in safe for long time.Thermal insulation materials and waterproof and cracking resistant mortar for aqueduct were prepared on the basis of the research on the features of the aqueduct. Sepiolite fibre and silica fume were used for improving the properties of thermal insulation materials, and SEM was used to analyze the microstructures of thermal insulation materials. At the same time the crumb rubber and organosilicon waterproof agent were used for improving the properties of the waterproof and cracking resistance. Furthermore the suitable thickness of the thermal insulation material was calculated.The results of the thermal insulation materials show that sepiolite fibre contributes to homodisperse of cement and glazed hollow bead, decreases consistency and segregation degree of thermal insulation paste, improves bleeding and isolating phenomenon and crack resistance, and the compressive strength and bending strength are improved under the condition of coefficient of heat conduction basically keeps constant. The proper amount of silica fume contributes to improve the fluidity, increases the compressive strength and bending strength, decreases water absorption rate of the thermal insulation materials.The results of the waterproof and cracking resistant mortar show that both crumb rubber and re-dispersible latex powder could increase the flexibility, while crumb rubber has negative influence on the compressive strength, bending strength and bonding strength. And the compressive, bending and bonding strength will decrease a little when the two are used together. So the comprehensive properties are increased but the cost is decreased. Both external application and doped organosilicon waterproof agent could increase waterproof performance for short-term and long-term, but the doped one could decrease the difficulties of construction.Through hypothesis and conversion, the difficult 3-dimensional heat transfer analysis will be simplified to 1-dimensional plate heat transfer analysis. Under the assumptive conditions, according to the formula between temperature difference and thickness, it could be calculated that 3cm is suitable thickness, when the temperature difference is lower than 10℃on the assumed conditions. So the large-scale aqueduct will operate stably for long time.