183 / 2022-04-30 20:44:19

A Multi-scale Constitutive Model of Engineered Cementitious Composites

ECC; constitutive law; multi-scale model; randomness

Engineered cementitious composites (ECC) has been utilized in reinforcement of concrete structures for its excellent mechanical properties. Unlike the brittleness of concrete, ECC behave superior high tensile strain capacity and strain hardening behavior under tension condition due to the bridging behavior of fiber. In this paper, a multi-scale constitutive model is proposed for ECC based on the fiber bridging effect.



On micro-scale, single fiber pullout test was conducted to investigate the effects of fiber embedment length (L_e) and inclined angle (φ) on the fiber pullout behavior of PE fiber in matrix. Then a prediction model whose key parameters are obtained from test results is established based on classical micromechanical model. The validity of proposed model is verified by comparing with the test results.



With single fiber pullout behavior is captured by proposed model, the meso-scale single crack bridging stress-separation constitutive law is available by summing the contribution of each fiber cross the crack plane, the randomness of fiber distribution and discreteness of fiber-matrix interface properties are considered by the corresponding parameters generated follows the respective probability distribution function, a satisfactory agreement with experimental results of single crack separation test is shown.



On macro-scale, the tensile behavior is simulated by series connecting several single crack bridging-separation laws generated randomly as above description, and the tensile capacity is governed by the minimum bridging stress, the simulation results were validated with tensile test of ECC showing great agreement. The connection of micro-meso-macro scales is logically clear, the discreteness of materials is considered in every scale of the proposed model.