พฤติกรรมรอยต่อคอนกรีตสมรรถนะสูงเสริมเส้นใยของคานคอนกรีตสำเร็จรูป

Abstract

Currently, precast concrete structures are gaining popularity in large-scale construction projects, such as staircases, floor slabs, beams, columns and walls. The most critical part of using precast components is the strength of the connections between these components, such as the connections between column and beam or beam and beam. Ensuring the quality of these connections is challenging because there are many external factors to control. Therefore, it is seen that the connections between beam and beam can be made by using reinforced steel bars like traditional steel connections. High-performance concrete is used instead of ordinary concrete in the gap. The strength of high-performance concrete is approximately 100-160 MPa, which is significantly higher than regular concrete. Thus, this research studies the behavior of connections between beam and beam with high-strength concrete, where reinforced steel bar is connected by traditional steel connections and the connection points of concrete are made with high-strength concrete and non-shrinking cement. The tests are conducted in a 4-point bending configuration with the objective of evaluating the performance of the connections in transmitting forces between the beams and observing critical failure phenomena of the connection. The tested beams have dimensions of 150 mm in width, 150 mm in height, and 700 mm in length. The concrete is designed with a standard cylinder compressive strength of 32 MPa at 28 days, and the steel reinforcement has a diameter of 12 mm with a quality grade of SD40. The depths of high-strength concrete are divided into three levels i.e. 50 mm, 75 mm and 100 mm. A total of 30 samples are prepared and tested under the specified variables in sets of three samples. The testing data is recorded deformation patterns, crack propagation, and response to loads. The results shown that the splice length of 9 times the diameter of the reinforcement steel and a depth of 100 mm of high-strength concrete can support the highest load, although it is still less than a beam without a connection.