The Effects of Dolomite Powder Content and Type on the Yield Stress Relationship between Self-Compacting Mortar and Paste

Self-compacting concrete (SCC), known for its excellent fluidity and self-compacting ability, is widely used in civil engineering. To enhance the comprehensive performance of SCC, dolomite powder (DP) is integrated as a substitute for cement. This study aims to analyze the impact of DP on the yield stress relationship between self-compacting mortar (SCM) and self-compacting paste (SCP) from a multi-scale perspective. A new predictive model for the yield stress relationship between SCM and SCP incorporating DP is established by improving the n value in the existing ϕe model, which characterizes the sensitivity of the mortar yield stress relative to changes in the paste yield stress. By conducting mini-slump flow tests on nine sets of cement–DP mixtures, it is found that DP impacts the yield stress relationship between SCM and SCP mainly through changes in the inter-particle filling effect, and the n value in the predictive model is roughly between 2.4 and 3.6. When the DP content is kept constant and the particle size is changed, the n value shows a strong positive linear relationship with the packing density of the paste (ϕe,p). The relationship between n and ϕe,p is derived using the linear fitting method, which improves the model’s predictive accuracy by 95.2%.