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Early-Age Cracking Behavior of Concrete Slabs with GFRP Reinforcement
Hossein Roghani1, Antonio Nanni1, John E Bolander2
1Department of Civil and Architectural Engineering, University of Miami, Coral Gables, FL 33146, USA.
Materials (Basel, Switzerland)
|August 12, 2023
Summary
Glass fiber reinforced polymer (GFRP) reinforcement effectively restricts early-age plastic shrinkage cracking in concrete slabs. While initial crack formation isn't affected, GFRP limits crack width over time.
Area of Science:
- Civil Engineering
- Materials Science
- Construction Technology
Background:
- Early-age cracking in concrete significantly impacts structural integrity and service life.
- Plastic shrinkage cracking is a critical concern in concrete slabs, influenced by environmental factors and material properties.
- Glass Fiber Reinforced Polymer (GFRP) is increasingly used as an alternative reinforcement to steel in concrete structures.
Purpose of the Study:
- To investigate the effectiveness of GFRP reinforcement in mitigating early-age plastic shrinkage cracking in concrete slabs.
- To compare the performance of GFRP reinforcement against steel reinforcement and unreinforced concrete under controlled plastic shrinkage conditions.
- To understand the influence of early-age bond characteristics between GFRP bars and concrete on crack development.
Main Methods:
- Experimental testing of nine small-scale concrete slab specimens under controlled evaporation rates.
- Acquisition of crack development images for crack width estimation.
- Early-age bond tests for GFRP and steel reinforcement.
- Penetration resistance tests for concrete strength and setting time measurement.
- Three-dimensional numerical modeling using a Voronoi cell lattice model.
Main Results:
- GFRP reinforcement, similar to steel, did not influence the timing of crack initiation or initial crack openings during plastic shrinkage.
- Early-age bond tests revealed insights into the interaction between reinforcement and concrete under drying conditions.
- Numerical simulations, incorporating measured bond properties, confirmed that GFRP reinforcement restricts crack development, but does not entirely prevent it.
- Crack width estimations indicated a reduction in cracking severity with GFRP reinforcement compared to control specimens.
Conclusions:
- GFRP reinforcement demonstrates effectiveness in controlling and reducing the severity of early-age plastic shrinkage cracking in concrete slabs.
- The study provides valuable data on the performance of GFRP in early-age concrete cracking, supporting its application in construction.
- Further research can explore long-term performance and optimization of GFRP reinforcement strategies for enhanced crack control.
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