Understanding the effects of mix proportion parameters on the dynamic stability of ground limestone mortar based on the velocity of particle and paste film thickness

Abstract

Dynamic stability is the key performance affecting the workability of mortar and also has important effects on the mechanical properties, durability, etc. In this study, the influences of mix proportion parameters including content and fineness of ground limestone, water to binder ratio and aggregate to binder ratio, etc. on dynamic stability were studied based on slump-flow test and flow trough test. Results showed that the two methods are consistent in evaluating the dynamic stability. The increase of ground limestone fineness and aggregate to binder ratio can improve the dynamic stability. The ADG and DSI can increase by about 16.7% and 142% when W/B increases by 1%. With the increase of 0.1% of SP content, the ADG and DSI can increase by about 58.5% and 295%.The velocity of a single sand and paste film thickness of mortar were determined to explore the reasons for dynamic stability changes. It was found that the velocity of a single sand can not characterize the effect of aggregate content on the dynamic stability and the paste film thickness fails to explain the influences of rheological properties of cement paste on the dynamic stability. The combination of velocity of a single sand and paste film thickness can provide a new view to understand the variation of dynamic stability.