Influence and Mechanism Analysis of Particle Size Distribution of Multi-System Mineral Admixture on Concrete Performance

Abstract

To explore the effect of mechanical activation on the particle size distribution of the composite admixture a self-designed test jet mill is used. We have studied the effects of different specific surface areas of composite admixtures on the workability, mechanical properties and durability of concrete and combined X-ray diffraction (XRD) with scanning electron microscopy (SEM) to analyze the mechanism of concrete performance improvement. Results showed that, mechanical activation can significantly increase the content of particles below 3 um; appropriate increase in the specific surface area of composite admixture is conducive to improving the performance of concrete; As the specific surface area increases, the hydration activity of the composite admixture increases first and then tends to be stable; during the hydration process, more thin-plate Ca(OH)2 is converted into needle-shaped AFt, which improves the cement-based material and thereby improving the macro mechanical properties and durability.