Creep deformation characteristics of rubberised structural concrete: Fid-Bau Portal

Creep deformation characteristics of rubberised structural concrete

Otieno, M. / Mushunje, K.

Highlights • Increased drying shrinkage and creep of structural rubcrete. • Micro-cracking potential of structural rubcretes is not altered. • Deformation characteristics similar to conventional concrete.

Abstract The influence of replacement of fine mineral aggregates with crumb tyre rubber of different particle sizes (2.36, 1.18 and 0.425 mm) on creep and shrinkage of structural rubberised concrete (rubcrete) is investigated. Rubcrete specimens were made using plain Portland cement (PC), 0.60 w/b ratio, crushed andesite coarse aggregate and a 90/10 blend of, respectively, crushed fine andesite and crumb rubber aggregate. The crumb rubber sizes were not blended in the concrete, resulting in three rubcrete mixes. Drying shrinkage and creep was monitored for approximately 1 year. The results show that compared to mineral aggregate concrete (MAC) both drying shrinkage and creep of the rubcretes increased, respectively, by up to 20% and 10% with decrease in crumb rubber particle size. Minimal differences were observed between the drying shrinkage and creep of the rubcretes made with the 1.18 and 2.36 mm crumb rubber aggregates. The results also showed that the introduction of crumb tyre rubber in concrete did not alter the micro-cracking potential of the rubcretes. Ultimately, the findings clearly show that structural rubcrete has similar creep and shrinkage deformation characteristics to that of MAC of similar strength.