Improving the Performance of Concrete with Internal Curing (Part 2)-Shrinkage and Shrinkage Cracking (Recorded Presentation)

Video Transcription

Video Summary

The third module of the internal curing series focuses on shrinkage and shrinkage cracking in concrete. It highlights how shrinkage contributes to stress development, leading to early age cracking. Learning objectives include understanding the types of shrinkage, their causes, and mitigation strategies, particularly through internal curing.<br /><br />Shrinkage occurs when concrete loses moisture or cools, causing volume reduction. If restrained, this induces tensile stresses, potentially leading to cracking. The module explains Hooke's Law and the role of viscoelasticity, which helps to relieve stresses over time.<br /><br />The potential for cracking is influenced by factors like the elastic modulus and viscoelastic effects. Lower water-to-cement ratio concretes may exhibit more shrinkage due to a denser matrix and smaller pore sizes, leading to greater stress. Internal curing, using pre-wetted lightweight aggregates, provides water internally, filling vapor-filled spaces caused by chemical shrinkage, thus reducing shrinkage and cracking potential.<br /><br />The module also describes methods for measuring shrinkage and the benefits of internal curing in reducing stress and cracking, including plastic shrinkage cracking. Internal curing improves hydration, reduces shrinkage, and enhances concrete robustness against thermal and mechanical stresses. It ultimately leads to more durable concrete with a longer service life, reduced maintenance costs, and improved sustainability. Overall, internal curing stands as a critical advancement in addressing shrinkage-related challenges in concrete construction.

Keywords

shrinkage

shrinkage cracking

concrete

internal curing

stress development

early age cracking

viscoelasticity

elastic modulus

lightweight aggregates

hydration

sustainability