Structural behavior of beams cast using normal and high strength concrete containing blends of ceramic waste powder and blast furnace slag

Abstract

In general, the use of ceramic waste powder (CWP) in concrete production is limited to few percentages (i.e., less than approximately 10–15% of Portland cement), given the resulting decrease in concrete strength and durability. This paper seeks to assess the relevance of blending CWP with blast furnace slag (BFS) to foster pozzolanic reactions and reinstate the drop in strength and structural performance of reinforced concrete (RC) members. Two categories of normal- and high-strength concrete (NSC and HSC) mixtures possessing 34 and 71 MPa compressive strengths are tested in this program. The RC beams measured 2-m in length and were differently configured by steel reinforcements to assess the flexural and shear strengths as well as the bond to embedded spliced rebars. Regardless of the steel configuration, results showed that the structural properties curtail when the concrete mixtures are prepared with 10% CWP replacement rate. This was attributed to a dilution effect and higher CWP porosity that detrimentally alter the concrete microstructure and strengths. The drop in flexural, shear, and bond strengths was found to be fully restored with the use of ternary binder composed of 55% cement, 35% BFS, and 10% CWP. Such results are in line with the improved concrete strength and durability, revealing the relevance of blending CWP with BFS to foster synergistic effects and reinstate the structural properties of NSC and HSC beams. Findings of this work can increase the CWP added-value for the construction industry, while reducing the cement carbon footprint.

Keywords

• Ceramic waste powder
• Blast furnace slag
• Reinforced concrete
• Flexure
• Shear
• Bond