Evaluation of Compressive Fracture Zone Length of High-Ductility Cement Composite Materials Using Recycled Fine Aggregate Considering Eco-Friendliness

At present, addressing global environmental issues is a crucial challenge in conducting production activities. In the field of concrete, research on recycled aggregate concrete, which involves producing concrete using recycled aggregates extracted from demolished concrete blocks, is actively being conducted. In order to further promote the recycling of concrete, it is essential to develop new effective utilization technologies for example, aspects such as economic viability and environmental sustainability for recycled aggregates. In this study, using the acrylic bar method, uniaxial compression tests were conducted on R-DFRM specimens with different specimen dimensions and W/C ratios, to examine the effects of these variations on the compressive fracture zone length. From the results, compressive fracture zone length in high-ductility cement composite materials using recycled fine aggregate was found to depend on the specimen diameter, regardless of differences in height-to-diameter ratio and water-cement ratio. Using the estimation formula presented in this study, the compressive fracture zone length can be estimated from the specimen diameter and compressive strength of high-ductility cement composite materials using recycled fine aggregate, within the range of specimen diameters from 50 to 150 mm, and even when using recycled aggregates, similar mechanical behavior to that of natural aggregates was observed.