Strength, Elastic Modulus, and Creep of High-Strength Concrete Produced with Bagasse Ash and Recycled Concrete Aggregate

In this study, the mechanical properties of a high-strength recycled concrete (HS-RC) incorporating ground bagasse ash (GBA) were evaluated. Recycled coarse aggregate (R-CA) from concrete demolition was used as a full replacement for natural coarse aggregate (N-CA). The GBA was used to partially substitute 20-50 wt. % of the ordinary portland cement cementitious material. The results indicated that the replacement of N-CA by R-CA led to a slight reduction in the compressive strength of the concrete compared with that of conventional high-strength (CT) concrete. However, the R-CA had a clear negative impact on the elastic modulus and creep strain of the HS-RC. The HS-RC mixtures prepared with 20 wt. % GBA had a higher compressive strength than the CT concrete at later ages (90 days or more). Likewise, the GBA slightly reduced the creep strain, whereas the HS-RC with and without GBA had an approximately 20 % lower elastic modulus than the CT concrete. In addition, the creep strain of concretes containing R-CA and GBA was related to their modulus of elasticity and compressive strength, which could be calculated by a proposed equation and were compared with the results from the predicted model given by ACI 209.2R-08, Guide for Modeling and Calculating Shrinkage and Creep in Hardened Concrete.