Development of high early strength engineered cementitious composites

The concrete structures usually deteriorate due to the lack of durability. Some of the infrastructures require urgent maintenance. Therefore, it is essential to develop durable and high early strength repair materials that can achieve required compressive strength in a limited period in addition to sufficient deformability at later ages. In this study, emphasis was placed on developing new High Early Strength Engineered Cementitious Composites (HES-ECC) by using local wastes of Muğla. For this purpose, two types of cement were employed: calcium aluminate cement and white Portland cement to develop two control mixtures of HES-ECC. 5 % by volume of expanded glass or rubber beads was incorporated in the other four mixtures to tailor tensile ductility. The mechanical properties of developed HES-ECC such as compressive strength, flexural strength, deflection capacity, and abrasion resistance were investigated in addition to fresh concrete properties and stability. Moreover, non-destructive tests such as ultrasonic pulse velocity test, electrical impedance test, and resonance frequency tests were conducted to confirm the mechanical properties of developed HES-ECC mixtures. The results obtained from this study showed that the minimum compressive strength of 28.9 MPa and the minimum flexural strength is 7.1 MPa could be achieved at six hours. iv Moreover, the deflection capacities of all mixtures were more than 3 mm with deflection hardening behavior even after 28 days. Besides satisfactory drying shrinkage values and excellent abrasion resistance were obtained. Therefore, the developed HES-ECC can be concluded to achieve the goal set for its use as durable repair material. Keywords: High Early Strength Engineered Cementitious Composite, Calcium Aluminate Cement, White Portland Cement, Artificial Flaws.