Effect of Recycled Powder and Mineral Admixture on the Mechanical Properties and Microstructure of Concrete

In order to improve the utilization rate of recycled powder in concrete, the mechanical properties and microstructure of single-doped recycled powder concrete and compound recycled powder, fly ash and silica ash concrete were compared. The results show that the single-doped recycled fine powder and the three-way re-mixing have different degrees of influence on the compressive strength and pore structure of the concrete, and when the dosage is less than 20%, the compressive strength of the single-doped recycled fine powder is higher than that of the remixed concrete when it was combined, and the porosity was also reduced relative to the re-doping time. When the dosage is higher than 20%, the compounding effect is better than that of single doping, especially when the compounding is 30%, the compressive strength of the concrete in 28 d is increased by 33.4% compared with the single doping by 30%, and the total porosity and the proportion of large pores to total pores are reduced by 4.4% and 17.77%, respectively. This shows that when the amount of recycled powder is incorporated, it will adversely affect the concrete, but after adding fly ash and silica ash, it can play a synergistic effect to improve the composite cement matrix strength and pore structure of the concrete. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.