ผลกระทบของอัตราส่วนน้ำต่อซีเมนต์ต่อพารามิเตอร์การแตกหัก ของคานคอนกรีตมวลรวมหยาบรีไซเคิลแบบมีรอยบาก

Abstract

This research presents the effects of water- to- cement ratios (W/C) on compressive strength, tensile strength, and the fracture parameters of Recycled Aggregate Concrete (RAC). The Recycled Aggregate (RA) was used to replace 50 percent of natural coarse aggregate. Designed water-to-cement ratios were 0.55, 0.60 and 0.65, respectively. Saturated surface-dry pre-treatment was applied to improve the quality of RA and the specimens were cured at 28 days prior to the experiments. Two research methodologies were utilized in this research. The compressive and tensile strengths tests were carried out using cylindrical specimens for fundamental mechanical properties. At the same time, three different sizes of beams with notches in the middle were in similar shapes. The beams were used to test Three- point bending. The Three- point bending tests were examined to obtain the maximum transverse load that would be used to calculate fracture parameters using the Size-Effect Method. The test results of recycled aggregate concrete with increasing water to cement ratios showed that the percentage of compressive strength decreased by 3.03 and 5.05. Tensile strength decreased by 6.81 and 9.10, respectively. For fracture parameters, Stress Intensity Factor (SIF) decreased by 16. 56 and 32. 07, fracture energy release rate (𝐺𝑓) decreased by 16.56 and 32.07, and fracture process zone length decreased by 45.45 and 65.64, in this order. Inversely, the brittleness numbers ( 𝛽) were found to be increased.