Manufacturing Concrete with High Compressive Strength Using Recycled Aggregates

In this paper, a method of developing high-strength concrete from recycled aggregates is proposed based on particle packing optimization (PPO) methods and presoaking of recycled aggregates. A total of 300 samples of concrete manufactured using 100% recycled aggregates and natural aggregates were analyzed and tested at 7, 14, and 28 days. On comparing the soaked and unsoaked recycled concrete aggregates (RCAs), it was found that the water absorption in aggregates was time dependent, which affected the workability of the fresh concrete for low water-cement ratio (W/C). However, it was found that on soaking the aggregates the absorption of water was instant (not time dependent). It was also found that by soaking the recycled aggregates (RAs) prior to concrete manufacture results in concrete with higher compressive strengths and lower slump. The average compressive strengths achieved for the recycled aggregate concrete (RAC) was approximately 83.0 MPa. From the literature reviewed, this might be the highest ever recorded compressive strength from concrete manufactured using 100% recycled coarse aggregates. (c) 2018 American Society of Civil Engineers.