Monitoring autogenous shrinkage in cellulose microfiber-reinforced GGBFS composites using ultrasonic interferometry

Area of Science:

• Materials Science
• Civil Engineering
• Geotechnical Engineering

Background:

• Ground granulated blast-furnace slag (GGBFS) composites offer sustainable alternatives to traditional cement.
• Autogenous shrinkage in GGBFS composites can lead to cracking and reduced durability.
• Internal curing with cellulose microfibers (CMFs) is a potential strategy to mitigate shrinkage.

Purpose of the Study:

• To evaluate ultrasonic wave interferometry for monitoring GGBFS composite shrinkage.
• To assess the role of kenaf-derived CMFs in mitigating autogenous shrinkage through internal curing.
• To establish correlations between ultrasonic measurements and shrinkage in CMF-modified GGBFS composites.

Main Methods:

• Preparation of prismatic GGBFS composite specimens with varying CMF dosages (0-1.2 wt%).
• Conducting ultrasonic wave interferometry and autogenous shrinkage tests over 48 days in a controlled environment.
• Analyzing relative velocity changes and shrinkage strains to determine material behavior.

Main Results:

• Specimens with 1.2 wt% CMFs showed substantially lower autogenous shrinkage (-99.9 με) compared to those without CMFs (-537.6 με).
• Ultrasonic tests indicated higher relative velocity changes (10.9%) in CMF-incorporated specimens versus control (7.2%).
• Strong linear correlations (96.5-98.3%) were found between autogenous shrinkage and relative velocity change, specific to each mixture.

Conclusions:

• Ultrasonic wave interferometry is an effective non-destructive technique for monitoring shrinkage in GGBFS composites.
• Cellulose microfibers significantly improve dimensional stability and reduce autogenous shrinkage in GGBFS composites.
• CMFs show potential for enhancing the long-term durability of cementless GGBFS-based materials.