RC columns strengthened with engineered cementitious composite (ECC) jacketing

This article aims to study the uniaxial compressive behavior of reinforced concrete (RC) columns strengthened with engineered cementitious composite (ECC) jackets. For this purpose, two advanced ECC mixtures containing polypropylene fibers were designed, and ECC jackets were cast to confine fourteen circular column specimens. Longitudinal and transverse grooving, sandblasting, and abrading were used as surface preparation techniques to achieve better adherence of ECC jackets to eight control (reference) column specimens, while two specimens with no surface preparation but with the same jacketing were used as a reference. The four remaining concrete column specimens lacking either internal reinforcement or an ECC jacket were used as control. All the specimens were subjected to concentric loading to determine the efficiency of ECC jacketing in enhancing load-carrying capacity and ductility. The experimental results revealed that compared to the control column, the reference specimens subjected to longitudinal grooving as surface preparation and ECC jacketing exhibited improvements of up to 1.3 and 2.5 times in their load-bearing capacity and energy absorption, respectively. Besides, ECC jacketing in specimens with the longitudinal grooving method increased the reference columns’ initial and secant stiffness values by up to 3.2 and 1.6 times, respectively. Finally, the models reported in the literature were evaluated in terms of their ability to capture the stress-strain curves of the ECC jacketed RC columns used in the present study.