With the development of expressways, the T-beam design is becoming more and more popular. If there are problems in the T-beam production process, it will inevitably affect the project quality and leave potential project hazards. In order to effectively control the quality of the beam slabs and achieve a beautiful appearance, this paper, combined with the actual situation of the project site, through detailed research and analysis, found that there are five problems in the T-beam production and construction, and put forward improvement measures after analyzing the reasons. 

 First, there is a problem in the cleaning of the pedestal concrete: During the hoisting process of the T-beam, there are sundries or concrete garbage at the bottom of the beam slab, which affects the quality and appearance of the beam slab.

 Reason analysis: The number of pedestal rows in the precast beam yard is 3 rows, with 8 pedestals in one row. In order to make rational use of the land, the distance between the pedestals is relatively close. The commonly used pouring method is to put the concrete from the concrete transport vehicle into the hopper, and then use the small gantry crane to lift the hopper to the formwork above the beam slab to be poured, and then pour the concrete into the precast beam with the formwork installed. During the hoisting process, due to the loosening of the hopper gate, some concrete is scattered on the adjacent pedestals or other sundries remain on the pedestals. 

 Adopted measures: Before binding the precast T-beam slab reinforcement, the concrete or other sundries on the pedestal should be removed to prevent them from entering the T-beam concrete. 

 Second, there is a problem with the diaphragm: The reserved length of the main reinforcement at the diaphragm of the precast T-beam is inconsistent from left to right, resulting in insufficient lap length of the connecting main reinforcement of the subsequent T-beam diaphragms. 

 Reason analysis: 1. When constructing the main reinforcement at the diaphragm of the precast T-beam, the reserved length of the main reinforcement is inconsistent from left to right due to the workers' cutting or installation process; when installing the formwork, the workers touch the main reinforcement of the diaphragm, resulting in the main reinforcement being displaced, and the T-beam concrete is poured without being restored to its original position in time. 2. During the concrete pouring process, the workers' vibration causes the diaphragm reinforcement to be displaced or displaced and not to be reset in time.Adopted measures: Before pouring the concrete, self-inspection should be strengthened to measure whether the exposed length of the main reinforcement of the diaphragm meets the lap requirements. If it is found to be non-compliant, it should be corrected in time, and if there is a displacement phenomenon during the vibration process, it should be reset in time. 

 Third, there is a problem with the bellows treatment: There is a conflict between the reinforcement of the precast T-beam ledger plate and the bellows, and the conflicting reinforcement is cut off without any treatment. 

Reason analysis: During the process of binding the reinforcement and installing the bellows, when there is a conflict between the reinforcement of the precast T-beam ledger plate and the bellows, the phenomenon of cutting off the conflicting reinforcement will occur. The reason is that the workers do not carry out the reinforcement treatment in order to speed up the construction progress and pursue the completion of two or more precast T-beams in one day. 

 Adopted measures: After installing and positioning the bellows, the workers are required to carry out repair welding treatment on the cut-off conflicting reinforcement, lap treatment for the insufficient length, and the welding slag should be cleaned up in time. The embedding of the prestressed pipeline can be carried out while binding the reinforcement. At this time, the setting of the bellows should be taken into account, and after the bellows are threaded, some reinforcements can be bound. The prestressed pipeline should be positioned in strict accordance with the design coordinates, and measures should be taken to reinforce it to prevent displacement. The pipe interface should be wrapped with a sleeve and adhesive tape to prevent the cement slurry from infiltrating during the concrete pouring and causing the pipe to be blocked. During the reinforcement binding process, attention should always be paid to the laying of the reinforcement protective layer and the installation of the embedded reinforcement, especially the embedding of the end diaphragm and the transverse diaphragm embedded reinforcement. After the reinforcement and the prestressed pipeline are installed, the other side formwork should be erected in time, and the concrete pouring of the beam body can be carried out after passing the inspection. 

 Fourth, there is a problem with the thickness of the reinforcement protective layer: Insufficient attention is paid to the thickness of the reinforcement protective layer at the precast T-beam ledger plate, and it is found after testing that the thickness does not meet the design code requirements.

Reason analysis: Although the workers have tied the spacers to the reinforcement as required, the requirements for the protective layer thickness cannot still be met. The main reasons are: (1) The formwork installation touches the spacers, resulting in the plastic spacers falling off or being displaced. (2) Due to the deviation in the reinforcement processing, the annular reinforcement of the ledger plate is too large, and the spacers are crushed when the formwork is closed.Adopted measures: Before pouring the concrete, the reinforcement protective layer of the ledger plate should be inspected. If the above problems are found, the spacers should be replenished in time. 

 Fifth, there is a problem with the vibration construction: After the concrete formwork of the precast T-beam is removed, there is a large area of honeycomb and pitted surface. 

 Reason analysis: (1) During the construction process, the workers did not vibrate the concrete in place. (2) The fluidity of the concrete from the mixing station is poor and cannot meet the construction requirements. 

 Adopted measures: Strengthen the on-site management work. Once it is found that the fluidity of the concrete cannot meet the requirements, the concrete must be returned to the mixing station for treatment. If the temperature is high, the initial setting time of the concrete should be considered to prevent cold joints due to the failure to pour continuously in time. Appropriate water should be added under the guidance of the test and inspection personnel. The pouring of concrete starts from the low point and expands and rises layer by layer, maintaining a horizontal layering. The concrete pouring should be carried out continuously. If it must be interrupted for some reason, the interruption time should be less than the initial setting time of the concrete. If the allowable interruption time is exceeded, it must be treated as a working joint to ensure the concrete quality. In order to strengthen the tamping quality of the concrete, it is necessary to use a combination of internal vibrators and external vibrators for tamping; when the internal vibrator is vibrating, it is necessary to avoid contacting the reinforcement framework and the embedded prestressed pipeline to avoid displacement. 

 This paper discusses the six problems and improvement measures in the T-beam production and construction. Including the residue of sundries during the cleaning of the pedestal concrete, the inconsistent reserved length of the main reinforcement of the diaphragm, the improper treatment of the bellows, the insufficient thickness of the reinforcement protective layer, and the inadequate vibration construction. The reasons are analyzed, and the corresponding solutions are proposed. These problems seriously affect the project quality and must be paid attention to. We should strictly follow the improvement measures for construction, strengthen quality management. We call on the construction workers to improve their sense of responsibility, pay attention to every link, and ensure the quality of T-beam production.