1
.
The quantity of all materials for hot asphalt surface treatment by mixing method is almost the same as that by layer paving method, but the requirements for mixing, paving and compaction equipment are higher
.
At the same time, the specification requires that the paving thickness can only be controlled within 1cm, so the paving construction is more difficult
.
Its specification and quality shall meet the specification requirements
.
Attention: 1
.
Under special circumstances, this kind of seal layer can be kept for 2-3 years without damage to the base layer, and the upper layer can be paved without the need for adhesive layer treatment
.
Conclusion 1
.
Emulsified asphalt slurry seal is a thin layer construction technology of fine-grained asphalt concrete, in which graded stone, emulsified asphalt, water, additives and additives are fed, mixed and paved in proportion by slurry seal machine
.
The mechanization degree of slurry seal is very high
.
Before the construction of old pavement reconstruction, the pit, crack and other diseases should be treated
.
2
.
If the emulsified asphalt is mixed with appropriate amount of SBR, SBS and other modifiers, the sealing effect will be more ideal
.
In fact, the lower seal coat is a fine-grained asphalt concrete thin layer construction technology
.
The amount of asphalt and aggregate is controlled according to the maximum amount of 1200kg / km2 and 9m3 / km2 respectively
.
What kind of technology should be used in the construction of the lower seal coat should be determined based on the actual situation of the specific project, but no matter what kind of technology is used, we should strictly grasp the key points of the seal coat construction, so as to pay equal attention to the quality and safety, and achieve the high unity of efficiency and efficiency..
.
2
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Hot asphalt surface treatment by layer paving method, after heating asphalt to 150 ℃ – 170 ℃, mechanically spray it to the surface of semi-rigid or rigid base, and then evenly spread S14 aggregate
.
The type of emulsified asphalt should be based on the purpose of use, the type of mineral aggregate and the construction temperature
.
The new base course should be arranged after the end of curing period and quality acceptance
.
Natural sand, machine-made sand and stone chips can be used as the aggregate for seal coat
.
With the continuous accumulation of expressway construction experience and the continuous improvement of people’s understanding, domestic high-grade highways, such as Hangzhou Ningbo Expressway and Jinliwen expressway, all design the lower seal coat (adhesive layer and prime coat) in the structure, but some also equate the construction of lower seal coat with the construction of prime coat oil and adhesive layer oil
.
3
.
It has the characteristics of dense gradation and large amount of oil, so that the seal layer has good cohesiveness and compactness, and this compactness will be further improved with the increase of rolling times and high temperature paving and rolling of the surface layer, which really plays the role of bonding and water sealing
.
Cationic emulsified asphalt should be used when the construction is carried out at low temperature
.
The following conditions are suitable for the construction of semi-rigid and rigid base course surface of new expressway; when the old cement concrete pavement (including bridge deck pavement) is reconstructed into asphalt concrete pavement; when the compactness of asphalt pavement is difficult to grasp and the void ratio is large in rainy areas; when the pavement cannot be paved in a short time and vehicle traffic needs to be opened after the construction of base course; 2 It is necessary to select the asphalt materials, and the asphalt conforming to the “technical requirements for heavy traffic road petroleum asphalt” in the “technical specification for highway asphalt pavement construction” shall be used, and the variety source should be the same as the surface course
.
The pavement form of multi-layer asphalt concrete mixture pavement combined with semi-rigid and rigid base determines the important position of lower seal coat construction in this structural system
.
There are various schemes for the construction of the lower seal coat of the asphalt pavement of the expressway, but from the aspects of the compactness, the bonding ability, the waterproof characteristics, the strength index, the construction conditions, and the cost comparison and selection, the emulsified asphalt adhesive, the prime coat, and the emulsified asphalt slurry seal coat should be the more reasonable choice
.
Before the construction of seal coat, the surface of base course should be cleaned thoroughly to be clean and dust-free, and the curbs and artificial structures should be protected and sealed Traffic, reduce interference to ensure molding quality
.
This method is far away from the mechanism of seal coat in pavement structure system
.
Before the construction of seal coat, the surface of base course should be treated first
.
Anionic emulsified asphalt should be used for alkaline stone, or when the stone is in a dry state or when cement, lime and fly ash are used together
.
According to this construction scheme, although a more uniform lower seal layer can be formed, the density is not easy to master, and it is obviously restricted by the environment, like the layer paving method
.
The thickness of slurry seal coat used as lower seal coat is only 3 mm ~ 6 mm, which is thinner than that of hot asphalt surface treatment, and its cost is about the same
.
Slow cracking, fast cracking and slow cracking fast setting emulsified asphalt should be used respectively in the construction of prime coat, tack coat and slurry seal coat
.
One seal machine can pave more than 2000 m2 / h, and the traffic can be opened after one hour, so the speed is very fast
.
It can not be constructed in rainy days or low temperature seasons, and it is easy to oil in high temperature in summer, and it is stuck by vehicles and paver tracks, so it can not play a real role in the lower seal layer
.
It shall be clean, dry, free from weathering and impurities, with proper particle composition and good bonding ability with asphalt
.
3
.
3
.
The mineral aggregate gradation should be continuous, and the asphalt mixture should form a dense and uniform structure layer on the surface of the base by mixing, paving, rolling and other steps
.
According to this scheme, the requirement of asphalt spraying degree is high, and the amount of asphalt and aggregate is difficult to be accurately controlled, so it is difficult to form a smooth and uniform thin layer of asphalt mixture
.
