Long-Term Concrete Shrinkage Influence on the Performance of Reinforced Concrete Structures

Area of Science:

• Civil Engineering
• Materials Science

Background:

• Tension stiffening in reinforced concrete (RC) is crucial for structural serviceability.
• Existing models inadequately address concrete shrinkage, particularly long-term effects.

Purpose of the Study:

• To investigate the impact of five-year concrete shrinkage on the tension stiffening behavior of RC tensile elements.
• To quantify the reduction in cracking load and stiffness due to long-term shrinkage.

Main Methods:

• Experimental testing of RC tensile elements with varying reinforcement ratios and bar diameters after five years of shrinkage.
• Mathematical removal of shrinkage effects from experimental data.
• Comparison of experimental results with predictions from CEB-fib Model Code 2010 and Euro Code 2.

Main Results:

• Concrete shrinkage distinctly lowered the cracking load of RC members.
• Shrinkage caused a significant reduction in tension stiffening.
• Higher reinforcement ratios exacerbated the negative effects of shrinkage.
• Code predictions showed smaller relative errors when compared to shrinkage-free curves.

Conclusions:

• Long-term concrete shrinkage substantially degrades the tensile performance of RC members.
• Current design codes may underestimate shrinkage effects, though their accuracy improves when shrinkage is accounted for.
• Further research into long-term shrinkage effects on RC behavior is warranted.