Importance of bridge deck waterproofing

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In recent years, the design standard and construction technology of expressways built in China have significantly improved in terms of their overall level

in recent years, the design standard and construction technology of expressways built in China have significantly improved in terms of their overall level. However, early damage often occurs less than a year after opening to traffic, and the most common damage is water damage. For asphalt pavement, due to its high porosity and no waterproof effect, the infiltration and retention of water, under the combined action of temperature and load, will not only cause the loosening, spalling and pit damage of the surface course, but also cause the softening and strength reduction of the base course, and then induce more serious damage to the surface course. Similarly, cement concrete pavement also has similar problems. In addition, in road construction, various bridges account for a considerable proportion of the total mileage of the highway. In practical projects, problems such as water seepage of overpass deck, peeling of pavement, crushing of bridge deck and so on often occur. Research shows that water infiltration is one of the most direct and important reasons for these damages. In order to protect the bridge deck, prevent ruts or tracks from directly wearing the bridge deck, and thus disperse the concentrated load of the wheels, the bridge deck is usually paved with cement concrete and asphalt concrete. In order to meet the requirements of good waterproof, stability, crack resistance, durability and good adhesion between layers, a waterproof layer is generally set between the bridge deck pavement layers

there are many materials that can be used to lay waterproof layer in road and bridge construction, including various waterproof coiled materials, waterproof coatings and various plugging materials. However, among many waterproof materials, waterproof coating is the most widely used and used waterproof material in road and bridge waterproofing in recent years. This is mainly because the waterproof coating has the following advantages as a road and bridge waterproof: the waterproof coating is an amorphous material, which can be applied to the base course of various shapes, and can form a waterproof layer with no joint and good integrity; It can be sprayed, which is convenient for construction and high efficiency. The water emulsion coating can also be applied on the wet base course, which can shorten the construction period. Therefore, in recent years, with the vigorous development of highway construction, road and bridge waterproof coating has also developed rapidly, and the engineering consumption has increased year by year. However, due to the lag of the standard, the previous road and bridge waterproof coatings were mostly based on the standards of building waterproof coatings JC 408 and jc/t 894. In fact, building waterproofing is quite different from road engineering waterproofing in environmental and mechanical properties. The function of bridge deck waterproof layer is different from that of building waterproofing and that of underground engineering structures. The roof waterproof coating is not subject to load. Its function is to prevent rainwater from invading the roof concrete, corroding the stressed reinforcement in the concrete, and reducing the service life of the structure; The waterproof coating of underground structures is based on the roof waterproof, plus a constant water pressure; The waterproof materials used for roads and bridges bear the waterproof function under the condition of constant change of external strain force and shear force. In the early stage of construction, they must bear the naked grinding of construction equipment and the puncture of granular materials. After being put into operation, they must also bear the repeated action of driving and hydrodynamic pressure. 1 especially, the roads need to bear larger vehicle driving load and horizontal load, and their strength at the bend is greater. Because there are many curved and sloping bridges on the expressway, and the bridge slope is large, coupled with a large number of heavy-duty vehicles and fast speed, some bridge decks appear the phenomenon of asphalt concrete sliding after the bridge girder with coiled material as the waterproof layer is completed and opened to traffic. When the bridge bears the vibration load structure, the waterproof layer of the bridge deck should adopt flexible coating and coiled material. Compared with the two, the coating waterproof layer is better

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