Method for preparing masonry mortar by utilizing scrap grout of concrete mixing plant

The invention discloses a method for preparing masonry mortar by utilizing scrap grout of a concrete mixing plant. The method sequentially comprises the following steps: (1) taking a sewage mud precipitate of the concrete mixing plant, performing natural air drying, grinding into powder, thereby obtaining waste mortar powder; (2) weighing the following components in percentage by weight: 5-15 percent of cement, 15 percent of water, 64.5 percent of sand, 5-15 percent of waste mortar powder, 0.4 percent of water reducing agent and 0.1 percent of thickening agent; and (3) stirring and mixing the various components in the step (2) to be uniform, discharging, thereby obtaining the finished masonry mortar. The method is economic and environment-friendly, and the obtained masonry mortar has good mechanical property and heat conductivity coefficient.