ผลกระทบของอัตราส่วนน้ำต่อซีเมนต์ต่อพารามิเตอร์การแตกหักของคานคอนกรีตมวลรวมหยาบรีไซเคิลแบบมีรอยบาก

บทคัดย่อ

This research presents the effects of water-to-cement ratios on the fracture parameters of Recycled Aggregate Concrete (RAC) of which 50% of natural coarse aggregate was replaced by Recycled Aggregate (RA). Designed water-to-cement ratios were 0.55, 0.60 and 0.65 respectively. Saturated surface-dry was applied to improve quality of RA. The specimens were cured at least 28 days prior to the experiments. The compressive and tensile strength tests were carried out using cylindrical specimens. The results showed that the compressive and tensile strength decreased with the corresponding trend from other researchers. Meanwhile, three different sizes of geometric similarity notched recycled aggregate concrete specimens were tested for their fracture properties. Three-point bending tests were performed to obtain the maximum transverse load which will be used to calculate fracture parameters using the Size-Effect Method. The results showed that with the increasing of water-to-cement ratios, fracture parameters such as stress intensity factor, fracture energy release rate and fracture process zone length tend to decrease. Inversely, the brittleness numbers were found to be increased.