Preparation and research of air tightness machine-made sand concrete for gas tunnel
Air tightness machine-made sand concrete suitable for gas tunnel was prepared by adding air-tight agent and its influence on cement hydration was studied.The heat release and hydration products of cement were analyzed by isothermal calorimeter,XRD,thermogravimetric analyzer,scanning electron microscope and mercury injection method.The results show that,compared with the concrete without air tightness,the apparent permeability of concrete decreases from 497.50x10-18 m2 to 29.16x10-18 m2,the chloride permeability coefficient decreases by 54.96％,the drying shrinkage decreases by 8.63％,and the compressive strength increases by 11.2％at 56 d.According to the analysis,the addition of air-tight agent has no adverse effect on the generation of cement hydration products,compared with the sample without adding air-tight agent significantly reduces the large capillary pores(100～1000 nm)inside the cement hydration products,makes the hydration products more dense,and improves the structure of the transition zone of the concrete interface,so that the strength,air tightness and durability of the concrete can be improved.
gas tunnelair tightness concreteair-tight agentpore structure
万方数据
维普
