Effect of volcanic ash material on recycled aggregate and recycled concrete properties

In order to enhance the mechanical properties and durability of concrete, the reclaimed aggregate was strengthened by soaking in the composite slurry of volcanic ash material and cement.With the material of soaked slurry as variable, effects of the mixture of cement and different volcanic ash materials (fly ash and silicon powder) and the slurry concentration on the water absorption rate, porosity, apparent density and crushing index of the reclaimed aggregate were studied, and the reinforced reclaimed aggregate was used to make concrete.The influence of aggregate strengthening technology on compressive strength and splitting tensile strength of recycled concrete was analyzed.The test results show that the physical properties of the regenerated aggregate can be improved by volcanic ash, and the water absorption, porosity and crushing index of the regenerated aggregate can be reduced to a certain extent, and the apparent density of the regenerated aggregate can be increased.Compared with ordinary recycled concrete, the recycled concrete with reinforced aggregate also has a great improvement in mechanics.Among the three kinds of volcanic ash grout, the 60% concentration of CFS grout has the best strengthening effect.The compressive strength and splitting tensile strength of CFS-RRAC with reinforced aggregate can reach 88.5% and 86.4% of NAC strength respectively.