LAUSR

To investigate the effects of its composition and water–cement ratio on the expansion properties of a new sealing material, the factors which influence the expansion properties were identified. Subsequently, single-factor experiments were conducted to explore the effects of water–cement ratio and specific additives in a cement-based sealant on the expansion capability of the sealing material. Additionally, according to Box–Behnken experimental design principles, the rank of the important expansion factors were identified using response surface methodology. Finally, the optimal experimental conditions were obtained. The results show that the influencing factors, sorted by significance, are aluminum content (mixed with an equal amount of CaO) > water–cement ratio > gypsum content. The best mix for the sealant could be obtained with cement plus 0.56% aluminum (mixed with an equal amount of CaO) and 2% gypsum in slurry with a water–cement ratio of 0.6.