关键词: 分级粉煤灰;干混砂浆;最紧密堆积理论;颗粒级配

Abstract: Based on particle dense packing theory, the Andreasen equation is generally used to calculate powder packing for evaluating the grading of powder particles.By studying the effect of the same fly ash with different particle sizes on the performance of high loading fly ash dry-mixed mortar, the result shows that the packing curve using ultrafine fly ash significantly deviates from the original dense packing state. This micro-filling cannot achieve the reinforcing effect but also greatly reduce the strength.Therefore, using fly ash to replace cement in dry-mixed mortar, particularly for high loading fly ash, the complementary role of all particles should be considered for the better dense packing to increase the density and maintain the performance of dry mortar.

Key words: separated fly ash;dry-mixed mortar;dense packing theory;particle size distribution