Experimental Study On Prestress Loss Of Self-compacting Concrete Beam With Machine-made Sand

Machine-made sand self-compacting concrete is concrete with machine-made sand as fine aggregate,which can be filled with formwork only by its own gravity.In order to study the construction method of machine-made sand self-compacting concrete and accurately grasp the effective prestress of machine-made sand self-compacting concrete beams,in this paper,a full-scale(20m)machine-made sand self-compacting prestressed concrete beam was produced.Through experiments,the construction method of machine-made sand self-compacting concrete and the prestress loss of machine-made sand self-compacting concrete beam were studied.The main research ideas are as follows:1.Use machine-made sand self-compacting concrete to pour a 20-meter prefabricated T-beam,and arrange vibrating wire strain gauges,resistance strain gauges,anchor end dynamometers and resistance displacement meters inside and on the surface of the beam to measure the tension of the beam the pre-stress loss of each sub-item.2.Eight groups of cube test blocks,four groups of prism test blocks,and one group of shrinkage test block were poured to study the basic performance of self-compacting concrete with machine-made sand.3.Based on the construction of machine-made sand self-compacting concrete beams,the construction characteristics of machine-made sand self-compacting concrete are analyzed,compared with ordinary concrete construction methods,and construction methods suitable for machine-made sand self-compacting concrete are summarized.A comparative study of different curing methods was carried out,and recommendations for curing methods and strength testing methods for machine-made sand selfcompacting concrete were put forward.4.On the basis of the test,the friction prestress loss,anchor deformation and joint compression prestress loss,concrete elastic compression prestress loss,shrinkage and creep prestress loss are analyzed,and the results are compared with the “Highway Reinforced Concrete and Prestress The calculated values of Stressed Concrete Bridge and Culvert Design Code”(JTG 3362—2018)were compared and suggestions were made.