Effect of Recycled Powder on Properties of Cement Morta

The effects of two types of recycled micro-powder (concrete powder and brick powder) replacing part of cement on the mechanical properties of cement mortar were studied. The results show that the contribution of recycled concrete powder to concrete strength is slightly stronger than that of brick powder. In a certain range of dosage, the performance of recycled concrete powder is close to that of pure cement. When the content of recycled concrete powder is less than 10 %, the compressive strength and flexural strength of cement mortar will not be greatly affected: over 20% cement mortar strength will decrease significantly. When the grinding content of recycled concrete is 5 %, the strength of cement mortar is even increased by 4.5 %. The relationship between recycled brick powder content and cement mortar strength is almost linear to 20% limit. The more recycled brick powder content is, the more obvious the cement mortar strength decreases. The particle size of regenerated powder has a certain influence on its activity. After a certain time of ball milling, the activity of regenerated powder can be effectively increased, but the ball milling time is too long, resulting in very fine particles. The activity of regenerated powder increases slightly with the increase of ball milling time, but the effect gradually decreases after more than 1 h.