Fresh and hardened-state properties of self-compacting lightweight concrete reinforced with steel fibers

• Self-compacting lightweight concrete was produced with steel fibers.
• Structural efficiency factor for self-compacting lightweight concrete was assessed.
• Thermal characterization was performed to characterize self-compacting lightweight concretes.
• The use of lightweight and porous expanded clay aggregates was essential to obtain low values of autogenous shrinkage.

This paper presents the results of a comprehensive experimental characterization on the fresh and hardened state of self-compacting lightweight concrete (SCLC) reinforced with steel fibers. Two classes of SCLC were produced containing either coarse or coarse and fine lightweight aggregates. Steel fibers were used as reinforcement in fiber volume fraction of 0.5%. Slump flow, inverted slump flow and “V” funnel tests were performed to characterize the self-compacting behavior of the concretes. The mechanical behavior was evaluated by means of compression, tensile and flexural tests. Thermal characterization was performed by specific heat, thermal diffusivity and conductivity tests. Autogenous and drying shrinkage tests were also carried out in the study. The results showed slump flow within 600–700 mm without segregation even for fiber reinforced SCLC mixes. All mixes have shown 28-day compressive strength above 30 MPa and density within 1700–1900 kg/m3. The fiber reinforcement has increased the mechanical properties under direct tensile and bending tests. Adequate thermal insulation properties were verified when compared to normal-weight concrete. Moreover, autogenous shrinkages were around 150 microstrain. Finally, concretes containing coarse and fine lightweight aggregates presented higher drying shrinkage than those only coarse lightweight aggregate.

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