Enhancing time-dependent performance of internally cured self-compacting lightweight concrete

초록

This study aims to evaluate the effects of internal curing and steel fibers on the mechanical, creep, and shrinkage behaviors of self-compacting lightweight concrete (SCLC) for application as precast concrete. For this, curing regimes, coarse aggregate types, and four different volume fractions of steel fibers, ranging from 0.25 % to 1.0 % were considered, along with three different configurations of fibers. The internally cured SCLC by lightweight aggregate (LWA) reduced the specific creep up to 5.6 % compared to concrete with normal weight aggregate (NWA). Steel fiber incorporation in SCLC reduced the creep deformation by 5.2 %, while heat curing significantly reduced it by up to 60.4 %. A substantial decrease in autogenous shrinkage up to 43.5 % was observed due to the internal curing (IC) from LWA, whereas 5.9 % for drying shrinkage. Applying steel fibers in SCLC reduced both autogenous and drying shrinkage, with heat curing proving more effective in reducing drying shrinkage than autogenous shrinkage. The creep coefficients and autogenous shrinkage behaviors of SCLC specimens were simulated with several classical models. The EN-1992 model accurately predicted the creep coefficients of all specimens cured under heat conditions, whereas classical models did not simulate the autogenous shrinkage behaviors of SCLC over various stages of its development. Finally, a model of autogenous shrinkage for SCLC considering IC effect was proposed based on experimental results.

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