Analytical procedures for design of strain softening and hardening cement composites

Fiber reinforced concrete (FRC) can be designed to exhibit pronounced ductility, energy absorption capacity, post-cracking strength depending on the fiber type and volume fraction. FRC have been classified into two categories, namely, strain softening and strain hardening cement composites (SSCC and SHCC). SSCC and SHCC are ultra-ductile class of materials developed for applications in the large material volume usage in the cost sensitive construction industry. Strain hardening behavior can be obtained by adding relatively low volume (typically < 2%) of randomly distributed fibers and demonstrates a well formed distributed crack system. Mechanical properties under uniaxial tensile, flexural, and shear tests indicate superior performance such as tensile strength as high as 25 MPa, and strain capacity of 1-8%. Development of proper design and analysis tools are very essential to fully utilize these materials. Several approaches are presented in this paper for analysis, simulation, back-calculation, and design of strain softening and strain hardening cement composite systems, and are applicable to all classes of SSCC and SHCC such as steel fiber reinforced concrete, textile reinforced concrete, and ultra-high performance fiber reinforced concrete.