Abstract

Info

Author(s):: XU An-hua; GUAN Bo-wen; MA Hui; XIA Yu; WU Jia-yu; CHEN Hua-xin; 1. School of Materials Science and Engineering, Chang’an University, Xi’an 710061, Shaanxi, China; 2. Qinghai Transportation Research Institute, Xining 810001, Qinghai, China

Keywords:: road engineering; magnesium oxychloride cement; rheology; shear stress; plastic viscosity; Power-law model

Abstract:: The early hard and fast characteristics of magnesium oxychloride cement lead to the construction problems of the concrete with long-distance transportation, is difficult to stir and difficult to pump and so on, which limits the popularization and application of magnesium oxychloride cement material. The shear stress and plastic viscosity of magnesium oxychloride cement paste at different shear rates were measured by the rotational viscosity test. The Power-law model was used to fit the rheological curves of magnesium oxychloride cement, and the influence of the design parameters on the rheological properties of magnesium oxychloride cement were analyzed by the model. The results show that the Power-law model can be used to fit the rheological curves of magnesium cement slurry, and the rheological parameters such as consistency coefficient and rheological index can be described. The shear stress of magnesium oxychloride cement paste increases with the increase of shear rate. The plastic viscosity decreases rapidly and then tends to be stable. When the shear rate is the same, the shear stress increases with the increase of the amount-of-substance ratio of MgO to MgCl₂, and decreases with the increase of the amount-of-substance ratio of H₂O and MgCl₂. With the hydration of cement, the shear stress and plastic viscosity increase. When the amount-of-substance ratio of MgO, MgCl₂ and H₂O is 7∶1∶15, the paste is the most stable.