The objective of this program is to develop theoretical formulations and experimental testing techniques for modeling the fracture process in plain concrete and fiber reinforced concrete materials. Figure below shows the role of fibers in stopping a crack from propagation perpendicular to the fiber direction, and forming delamination cracks instead. Fiber pullout and slip in this case contributes to ductility of the matrix.
The role of fibers in formation of distributed microcracking in a cement based composite laminate is shown in the next figure. Note the formation of parallel microcracks. Figure below shows the distributed microcracking in a cement based composite laminates. Additional topics include closed loop testing of concrete, and composite materials.
The crack bridged by polypropylene fibers. The external crack bridged by polypropylene fibers in a fiber reinforce concrete sample
Finite Element Modeling of fiber toughening mechanism
Distributed cracking in continuous fiber cement composites
Crack Bridging in Fiber Reinforced Cement composites
B. Mobasher, C.Y.Li, “Finite Element Simulations Of Toughening In Cement Composites,” American Concrete Institute, Fall Convention, 1998, Los Angeles, CA.
Li, C. Y., and Mobasher, B.,”Finite Element Simulations of Toughening in Cement Based Composites,” , Journal of Advanced Cement Based Materials, 1998, 7, pp. 123-132. [Download]
Mobasher, B., and, Li, C. Y., “Effect of Interfacial Properties on the Crack Propagation in Cementitious Composites,” Journal of Advanced Cement Based Materials, Vol. 4. No. 3, Nov. Dec. 1996, pp. 93-106.[Download]
B. Mobasher, “Modeling Of Cement Based Composite Laminates,” ACI Special Publications, 2005, SP224 Thin Reinforced Cement Products and Construction Systems, pp.179-192. [download]
Mobasher, B., Peled, A., “Use of R-Curves for Characterization of Toughening in Fiber Reinforced Concrete,” Proceedings, International Conferences on Fracture Mechanics of Concrete and Concrete Structures (FraMCoS V) Vail Colorado, 2004. pp.[download]
Mobasher, B. , Advances in Modeling FRC Materials, International Workshop on Advanced Fiber Reinforced Concrete, Bergamo, Italy, Sept. 23, 2004 [download].
Mobasher, B., Pahilajani, J., Peled, A.,“Analytical Simulation of Tensile Response of Fabric Reinforced Cement Based Composites”, Journal of Cement and Concrete Research, in press. 2005. [download]