Abstract: With the steam curing technology, effective fast curing technique in prefabrication technology, the effect of atmospheric steam curing on the mechanical properties of variable types of self-compacting lightweight concretes and the combination of the properties of semi-lightweight self-compacting concrete are important engineering approaches, focused in this study, in terms of workable and lightweight concrete production that is easy to apply. The cement type (CEM I 42.5 and CEM II 32.5) and three types of aggregates (normal, pumice and raw perlite) were the parameters of the study, including three types of steam curing cycle. The manufactured concrete samples were not only tested for compressive strength and bending, but also for splitting tensile strength. The fresh and hardened unit weight, dimension check and ultrasonic pulse velocity observations were also obtained for all 108 concrete samples. The three steam curing cycles were about 36.5 hours for 65°C, 70°C and 75°C. These steam-curing cycles were designed according to predesign tests and literature. As a result, the cement type and aggregate effect on the steam curing regimes were obtained. The decrease in the compressive strength of lightweight pumice concretes by the curing temperature rise and the negative effects of CEM II 32.5 on the strength values were the other striking results of the tests.Abstract: With the steam curing technology, effective fast curing technique in prefabrication technology, the effect of atmospheric steam curing on the mechanical properties of variable types of self-compacting lightweight concretes and the combination of the properties of semi-lightweight self-compacting concrete are important engineering approaches, focuse...Show More