Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste

The conventional “one-pot” mixing method employed in concrete production restricts both efficiency and quality optimization. This study systematically investigates the effects of mixing duration and rotational speed on the compressive strength and microstructure of cement paste by varying these parameters. Results indicate that appropriately extending mixing duration and increasing rotational speed enhances the strength of cementitious paste. However, excessive duration or overly high speeds adversely affect strength. When the rotational speed is 250 r/min and the mixing time is 100 s, the compressive strength of the hardened cementitious pastes at all curing ages is good, with strengths of 50.1 MPa, 61.1 MPa, and 77.0 MPa at 3 days, 7 days, and 28 days, respectively. Microstructural analysis further reveals that this mixing condition produced lower porosity, denser morphology, and increased hydration product formation, collectively explaining the superior mechanical properties.