Deflections of reinforced concrete beams made with recycled and waste materials under sustained load: Experiment and fib Model Code 2010 predictions

Abstract

This paper presents experimental results of long-term behavior of reinforced beams made from natural aggregate concrete (NAC), recycled aggregate concrete (RAC), and high-volume fly ash concrete (HVFAC) under sustained load. Two 3.2 m span simply supported beams were cast from each concrete type and loaded after 7 and 28 days for a period of 450 days. Deflections, cracking, and strains were measured on the beams. Mechanical properties, shrinkage, and creep were measured on accompanying concrete specimens. Results showed similar mechanical properties of NAC and RAC and lower values for HVFAC. Shrinkage and creep were largest for RAC and smallest in the case of HVFAC. All beams had similar increases in deflections relative to their initial deflections. Deflection results are compared with fib Model Code 2010 predictions. Good agreement is found with results for RAC beams, whereas predictions for HVFAC beams show a significant overestimation of experimental results.