At present, the maintenance of cement concrete pavement is mainly to cover the poured pavement with old sacks or water it with plastic film. Although this pavement maintenance method is desirable, in construction projects, only the old sacks are covered in the middle of the panel, while the two sides of the panel are ignored. When watering, the two sides of the panel are not adequately watered, which results in the phenomenon that the concrete strength in the middle is high and the concrete strength in the two sides is low, which makes the stress on the edge of the panel very concentrated, and it is easy to form a gnawing edge under the action of heavy and overloaded vehicles. Incorrect customary practice factors. Incorrect practices are common problems of most construction teams. Although these habits will bring some convenience to the construction, they are potential hazards. These incorrect practices mainly include wrapping a plastic film on the steel mold to prevent slurry leakage. In the process of construction, these plastic films may fall into the concrete, so that the concrete slab is layered, so that the concrete cannot form a whole, and it is easy to fall off under the action of heavy and overloaded vehicles. Vibrating beam or paving leveler will directly pour the second concrete panel on the edge of the poured slab, which will damage or wear the edge of the first slab and easily cause the edge gnawing phenomenon of longitudinal and transverse joints of pavement. In addition, when installing dowel bar or pull rod, no bracket is used, which is also one of the reasons for the phenomenon of undercut caused by incorrect practice. Traffic control factors. The construction quality of cement concrete pavement also depends on the correct and reasonable traffic control. When the panel is still in the maintenance period, letting vehicles drive in will not only destroy the panel, but also cause the phenomenon of road biting. By observing the steel formwork used for pouring pavement slabs, it can be found that some concave-convex shapes and some irregular shapes will be formed on the surface of the steel formwork due to repeated use. When pouring concrete slabs with this steel formwork, irregular shapes will be formed, and under the action of heavy overloaded vehicles, gnawing edges will also be formed.

Cause analysis of longitudinal joint expansion of pavement

The so-called longitudinal joint expansion of pavement means that the concrete pavement expands 5 ~ 20mm； along the longitudinal gap of highway; The expansion of pavement longitudinal joints will cause the longitudinal joints to chew edges and pump mud. If the longitudinal joint of pavement expands seriously, it may pose a certain threat to the safe driving of vehicles. The so-called staggered platform refers to the steps formed at the joint and on the road surface on both sides of the joint. The installation of tie bars and dowel bars, as well as the construction technology of cutting joints, will cause the longitudinal joints of pavement to expand or the pavement to stagger.

2. 1 Installation coefficient of tie rod and dowel bar

Because there is no requirement in the highway construction code that the bracket must be used when installing the tie rod and dowel bar of the working joint, it is easy to ignore the influence of this factor on the engineering quality in the construction. If a bracket is not used to fix the dowel bar or pull rod in the construction process, it is easy to tilt the sensor bar or pull rod, and the length of concrete is also different, which can not play the role of force transmission or connection. Cement concrete pavement that can't meet the design requirements is prone to longitudinal joint expansion and dislocation.

2.2 slit construction technical factors

In order to avoid the formation of irregular burrs in joints, concrete must have a certain strength. However, it is difficult to cut the concrete pavement before the cement concrete block hardens and shrinks. Therefore, when carrying out slit construction, it needs to be carried out according to the strength of concrete. The most suitable time for grooving is when the compressive strength of concrete is 5 ~10 MPa. In order to prevent the slab from breaking, it is necessary to carry out slotting construction after concrete pouring 18 hours.

3 Cause analysis of cement concrete pavement damage caused by flood

Flood is the main cause of some damage to cement concrete pavement. During the construction period, cracks are produced by concrete shrinkage, and cracks are not cut in time, which leads to cracks and broken slabs on cement concrete pavement. During the construction of cement concrete pavement, contraction joints, longitudinal joints and expansion joints need to be set according to the design requirements of construction. If inferior caulking materials are used, it is easy to cause damage under the action of heavy vehicles, and the joints will become the entrance of the lower base of the rainwater injection plate. Under the long-term immersion of rain, freeze-thaw splitting and the action of heavy trucks, a kind of running water will be washed out under the slate. After repeated washing, slurry will appear, and the lime soil under the board will be hollowed out. After a certain area is formed, it is easy to break under the action of heavy trucks.

4 prevention and control measures of diseases caused by construction technology

By analyzing the diseases caused by the construction technology of cement concrete pavement in the construction process, this paper summarizes the problems existing in the construction, and provides the basis for solving these diseases. In the process of construction, these diseases seriously reduce the service life of cement concrete pavement, so it is necessary to improve the construction technology to prevent or reduce the occurrence of diseases. At present, some methods to improve the construction technology are put forward: ① appropriately extend the time of formwork removal in cement concrete pavement construction, and generally set the time of formwork removal after 24 hours. (2) To improve the construction technology of formwork removal workers, it is required that the formwork removal workers should be patient, and the steel formwork should not be knocked with a sledgehammer during formwork removal. ③ Pay attention to the maintenance of the edge of cement concrete pavement slab. ④ Traffic problems in open traffic construction should be implemented reasonably. The concrete slab that is still in the curing period cannot be opened to traffic. ⑤ Incorrect construction habits should be corrected during construction. In the aspect of preventing slurry leakage, instead of wrapping plastic film on the steel mold, high-grade mortar can be used to seal the bottom seam of the steel mold, and 6×6cm bubble film can be used to seal the seam between the pull rod and the dowel bar. The construction of the second floor block can only be carried out after the anti-vibration board is placed on the first floor block that has been poured. ⑥ During the construction of the first slab of concrete pavement in Shuang Fu, the middle formwork shall be poured 1~2cm. During the construction of the second slab, the redundant 1~2cm concrete shall be removed first. During the construction of transverse construction joints and expansion joints, the joints should be cut first and then poured. When constructing the road surface with separate lanes, two slabs should be poured at the same time, and then cut from the middle with a seam cutter according to the false seam setting. ⑦ When installing dowel bars of expansion joints, not only brackets should be used, but also brackets should be used to fix longitudinal seam lacing bars or working seam dowel bars, so as to avoid the influence of the inclination of lacing bars and dowel bars on force transmission and connection. Today, formwork construction should be carried out when the cement stabilized base is not fully constructed. Under the new situation, the task shouldered by highway departments is arduous and arduous. We should further emancipate our minds, strengthen the strategic, overall and forward-looking research on highway development, promote the transformation of highway work from traditional mode to innovative mode, and constantly create a new situation in highway development.

For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd