Compressive Strength of Square Short Concrete Columns reinforced with GFRP Bars produced with Recycled Demolition Aggregate

This study experimentally investigated the compressive strength of short concrete columns reinforced with steel or Glass Fiber Reinforced Polymer (GFRP) bars, using normal aggregate, Recycled Demolition Aggregate (RDA), or Recycled Demolition Concrete (RDC). The study variables included the concrete aggregate type, percentage of aggregate replacement, percentage of cement replaced by Micro Silica Fume (MSF), percentage of added Super-Plasticizer (SP), and the main reinforcement material. Twenty column specimens with dimensions of 150 mm × 150 mm × 700 mm were tested, with ten of them having been reinforced using steel bars and ten using GFRP bars. The results indicated that columns with GFRP bars had higher ultimate load values than their steel-reinforced counterparts. However, the ultimate load of the columns with replaced aggregate was lower than that of the reference column with normal concrete and decreased with an increasing percentage of replaced aggregate. These findings provide insights into the potential use of recycled demolition materials and GFRP reinforcement in short concrete columns while highlighting the impact on compressive strength and ductility.