**block water leakage of the highway bridge
In recent years, the early damage of highway bridge deck pavement and the leakage phenomenon of hinge joints of plate girders have caused people to pay attention to the construction technology and materials of the waterproof sealing layer of bridge deck. Choosing an appropriate type of waterproof sealing layer can not only play a good waterproof plugging effect, ensure the safety of the bridge main structure, but also can extend the service life of the bridge deck pavement and reduce the cost.
Excellent bridge waterproof plugging layer should have the following characteristics:
1. It has good adhesiveness with the bridge concrete surface, it isn’t peeling, and it does not fall off.
2. It can bond with asphalt concrete deck pavement and integrate into one.
3. It’s impervious to water, puncture resistant, has a certain degree of tensile strength and ductility conform to the deformation.
4. There is no special requirement for the quality of the surface of the bridge concrete deck, and construction is easy.
I. Form of waterproof plugging layer
High content SBS modified bitumen waterproof plugging layer:
The high content SBS modified asphalt has a ductility of more than 60cm, which has low requirements for the smoothness of the bridge concrete deck. It is only necessary to thoroughly clean the bridge concrete deck in construction. As the modified asphalt requires higher temperature to average spraying, a high performance sprinkler with automatic heating and automatic control of the spraying amount is required.
II. Application effect
Construction of high content SBS modified bitumen waterproof plugging layer is tedious and fast, and it has excellent adhesive properties with both cement concrete and asphalt concrete. Sprinkling 2kg per square meter will form a more than 2mm thick asphalt membrane on the deck surface. The outer layer with more than 70% clean stone layer effectively avoids the sticky and skidding problems of wheels when paving asphalt concrete. When the asphalt concrete is paved, the hot mixture and the waterproof plugging layer are tightly bonded to form a whole, which is a waterproof plugging material with low cost and excellent water plugging effect.
III. Construction control points of the bridge waterproof plugging layer
Attention in waterproof plugging layer construction :
1. Clear laitance of concrete on bridge deck. The so-called laitance refers to the thin skin that was formed when the surface was formed or the mortar that was left behind during construction, and the center of empty protrusions was not unfilled. All the cement surface mortar itself could not be completely removed or resurfacing.
2. Thoroughly clean the bridge surface and there should be no dust and debris. There must not be vacancy or bulge on the membrane, otherwise it cannot fit tightly.
3. Strictly control the spray volume or construction process so that it reaches the corresponding quality specifications.
4. Strictly control the entry data, the same kind of waterproof plugging materials have greatly difference in quality divided by grades and the origin. The quality of the incoming materials should be strictly controlled in accordance with the contract request to ensure the waterproof plugging effect.
IV. Relationship of the bridge deck pavement damage and waterproof plugging layer
Causes of early bridge deck pavement damage includes inappropriate waterproof plugging layer materials and construction quality. Excessively thick waterproof plugging layer and poor adhesion waterproof plugging layer make the asphalt concrete pavement layer shift and loosen under the repeated action of heavy traffic, resulting in damage to the bridge deck. The key to avoiding early damage to the bridge deck pavement is to deal with the permeability issues of the asphalt concrete pavement, and to avoid the form of a thin interlayer or non-sticky layer between the asphalt concrete bridge deck pavement and the concrete bridge deck due to the construction of the waterproof plugging layer. Therefore, it is not recommended to use waterproof plugging materials with poor adhesion and membrane under heavy traffic.
(Sourcing: Club of Waterproof Enterprises)
