Title: Shear Behavior of Lightweight Self-Consolidating Concrete Beams Containing Coarse and Fine Lightweight Aggregates
Author(s): Ahmed T. Omar and Assem A. A. Hassan
Publication: Structural Journal
Appears on pages(s): 175-185
Keywords: aggregate interlock; cracking behavior; design equations; lightweight self-consolidating concrete; shear strength
This paper aimed to investigate the shear strength and cracking behavior of large-scale lightweight self-consolidating concrete (LWSCC) and lightweight vibrated concrete (LWVC) beams containing expanded slate coarse aggregates (ESCA) and expanded slate fine aggregates (ESFA). The authors explored different replacement levels of normal-weight coarse or fine aggregates by ESCA and ESFA to optimize successful LWSCC mixtures with minimum possible density and maximized compressive strength. The variables were different types of lightweight aggregate (either ESCA or ESFA), coarse-to-fine aggregate ratios (0.5 to 1.5), and total binder contents (550 and 600 kg/m3 [34.3 and 37.5 lb/ft3]). The developed mixtures were also used to cast nine large-scale beams without shear reinforcement to examine their shear strength and cracking behavior. The performance of code-based expressions in predicting the shear resistance of the tested beams was also investigated in this study. The results indicated that it was possible to develop expanded slate LWSCC with a minimum possible density of 1855 kg/m3 (115.8 lb/ft3) and compressive strength of 51.2 MPa (7.42 ksi). LWSCC mixtures developed with ESFA showed relatively higher flowability and passing ability compared to mixtures developed with ESCA. Although it was possible to reach lower density LWSCC when ESCA was used, mixtures developed with ESFA showed relatively higher strength-density ratio and higher normalized shear load by approximately 18% compared to LWSCC developed with ESCA. The results also showed that all code-based design equations were too conservative in predicting the ultimate shear strength of the tested beams; however, Eurocode 2 showed the closest predictions.