Design of Hybrid-Fiber Reinforcement for Shrinkage Cracking by Crack Width Prediction

The use of fiber reinforcement to reduce shrinkage cracking is becoming increasingly common. The effectiveness of fiber reinforcement can be enhanced using multiple types of fibers. A means of predicting the shrinkage performance of hybrid-fiber reinforcement would facilitate its design. A model to predict shrinkage crack widths in restrained ring shrinkage tests is being developed. The ability of the fibers to transfer stress across a crack and free shrinkage behavior are used to determine crack width. To facilitate calibration of the model, a procedure for establishing tensile performance from flexural test data using fracture mechanics has been developed. The crack width model and the procedure for predicting tensile performance are presented. The initial phase of calibrating the model, verification of the tensile performance prediction, is discussed.