Hybrid methods to improve microstructure of recycled concrete and brick aggregate for high-grade concrete production

Abstract

Carbon-conditioning or chemical permeation methods can provide excellent microstructural improvement to recycled concrete and brick aggregate, however, the applications have its limitations. Further, recycled brick aggregate cannot be effectively carbon-conditioned with conventional methods as it contains only trace amounts of reactive materials. It is thereby a necessity to use hybrid methods involving dual technologies combining carbon-conditioning and chemical permeation for its improvements. This paper is focused in developing a novel hybrid method for improving the microstructural properties of recycled concrete aggregate and recycled brick aggregate for concrete usage. This study conducts particle density, water absorption and crushing value tests in measuring the physical improvements achieved with the novel hybrid method; and utilizes variety of chemicals and a reaction chamber for carbon conditioning for aggregate treatment. The study evinces that both the recycled concrete aggregate and recycled brick aggregate experienced significant improvements with 10-mm and 20-mm recycled concrete aggregate and 10 mm recycled brick aggregate exceeding the density of virgin aggregate. Mg(OH)2 (s) + CO2 (g) treatment for recycled concrete aggregate and Ca(OH)2 (s) + Mg(OH)2 (s) + 2CO2 (g) treatment for recycled brick aggregate can be considered as potential candidates for optimal hybrid treatment methods.

Tensile Mechanical and Stress-Strain Behavior of Recycling Polypropylene Fiber Recycled Coarse Aggregate Concrete

“…To reduce the RCA water absorption to prevent RPF RCA concrete water cement ratio changes [34][35][36], the mixing water of recycled concrete is hydration water and additional water; the additional water is determined by the water absorption rate. The number and mix ratio of all specimens in this project can be seen in Table 4.…”

Macroscopic and Microscopic Investigation of Gypsum Slag Cement-Stabilized Recycled Aggregate Base Layers

“…As research on recycled aggregates continues to expand, various treatment methods have been identified to improve the microstructure of recycled aggregates. These methods include chemical or carbon treatments, combined treatments, thermal chemical techniques to remove cement paste from fine recycled aggregates, and the application of recycled materials in soil improvement [ 4 , 5 , 6 , 7 ]. In an effort to promote economic and environmental sustainability in the construction industry and to optimize the utilization of recycled concrete aggregates, scholars have proposed a novel model.…”