A method of using carbon dioxide to strengthen recycled concrete fine aggregate

Abstract

The invention discloses a method for reinforcing recycled concrete fine aggregate by using carbon dioxide, which comprises the following steps: (1) calcium hydroxide solution or calcium salt calcification treatment: spreading recycled fine aggregate prepared from construction waste on a tray, spraying a calcium hydroxide or calcium salt solution, and stirring uniformly; (2) CO2 curing: putting the recycled fine aggregate subjected to calcium hydroxide solution or calcium salt calcification treatment in a closed carbonization box, and carrying out carbonization curing until the surface is completely carbonized; and (3) recycled mortar preparation: preparing recycled mortar with the substitution rate of 100% by using the treated recycled fine aggregate. Compared with the unreinforced recycled aggregate, the crushing value of the recycled fine aggregate prepared by the method is lowered by nearly 45%, and the water absorptivity is lowered by nearly 53%. Compared with the recycled mortar prepared from the unreinforced recycled aggregate, the consistency of the recycled mortar prepared by the method is enhanced by 42% or so, the 7d strength of the mortar is enhanced by 15-26%, and the 28d strength can be enhanced by 17-24%.

Description

technical field

[0001] The present invention relates to a method using CO 2 The invention discloses a method for intensifying treatment of recycled concrete fine aggregate, which belongs to the technical field of recycling of construction waste and production of building materials. Background technique

[0002] Processing waste concrete into recycled aggregate for the preparation of recycled concrete not only solves the problem of environmental pollution, but also realizes the reuse of resources and reduces the waste of resources and energy. However, compared with natural aggregates, recycled aggregates have a large number of fine cracks inside, high crushing index value, and high water absorption rate. The working performance, mechanical properties and durability of recycled cement products prepared by using recycled aggregates are also difficult to meet engineering requirements. Therefore, strengthening recycled fine aggregate to improve the performance of recycled mortar...