Abstract
This paper reports on a combined experimental and numerical modeling investigation of cracking of concrete slabs with FRP reinforcement. At this stage of the project, attention is given to early-age cracking driven by plastic shrinkage, preceding longer term considerations of cracking resistance over the service life of field applications. Small-scale slab specimens are subjected to controlled evaporation rates. Images of crack development are acquired periodically, from which crack width estimations are made. Comparisons are made between slabs reinforced with conventional steel and those reinforced with FRP, along with control specimens that lack reinforcement. During the period of plastic shrinkage, the time of crack initiation and subsequent crack openings do not appear to be influenced by the presence of the reinforcing bars.
The numerical modeling component of the research is based on a Voronoi-cell lattice model. The relative humidity, temperature, and displacement fields are discretized in three-dimensions, which allows for a comprehensive investigation of fracture development. For the reduced bond properties that are expected at early ages, the simulations confirm that cracking behavior is not significantly influenced by the presence of the reinforcing bars.