Abstract: In order to evaluate the influence of the recycled aggregate content on the shear strength of the collapsible loess soils, the optimum moisture content and maximum dry density of collapsible loess with different recycled aggregate content were determined by preparing test samples with a heavy compactor reaching the degree of compaction of 98% and the direct shear tests were performed. The results show that with the increase of the recycled aggregate content, the maximum dry density of the collapsible loess improved by the recycled aggregate first increases and then decreases, while the optimal moisture content gradually decreases. The cohesion and the internal friction angle of the collapsible loess improved by the recycled aggregate first increases and then decreases. The cohesion of collapsible loess improved by the recycled aggregate from the construction waste first decreases, then increases and then decreases, while the internal friction angle first increases and then decreases. When the content of the recycled aggregate from the construction waste is 40%, the cohesion and the internal friction angle reach the maximum values.

Key words: Recycled Aggregate from Construction Waste, Collapsible Loess, Shear Strength, Optimal Moisture Content