欧美日本一线视频,狼友视频少妇向日的日子,欧美猛交ⅹxxx乱大交视频,一级不卡中文字幕精品片

   With the speeding up of highway construction in China, the paving technology of cement concrete pavement slipform machinery-curbstone slipform paver has been widely promoted and applied, and more and more large, large, medium and small bridges, overpasses, The technical problems of mechanized pavement of single-double-layer reinforced concrete bridge (culvert) surfaces of passages, culverts, and bridgeheads need to be solved through research and engineering practice.

   Due to the high overall smoothness and durability required of highways, technically, cement concrete pavements, reinforced concrete bridge decks, and reinforced concrete decks at bridge heads are required to achieve continuous paving by curbstone slipform pavers. In order to improve the overall smoothness of the cement concrete pavement, the pavement of extra large, large, medium and small bridges, culverts and passages is paved with curbstone slipform paver when the pavement is slipped. In this way, a high-density, high-flatness bridge deck with the same quality as a slipform paving cement concrete pavement can be obtained. When a motor vehicle runs through these continuously paved bridges (culverts) at high speeds, it is not felt that they are passing through the bridges and culverts, and there is no bumping vibration bumps and no need to decelerate.

   Along the highways in China, due to the large population and dense villages, except for some remote provinces and regions, on average there are more than 3 bridges and culverts and passages per kilometer of highways. If we use the curbstone slipformer for mechanized construction, we can only pave the pavement, and we cannot continuously pave the reinforced concrete bridge deck. The bridge (culvert) surface and the slab are manually constructed, which will inevitably cause slipform machinery that will seriously affect the cement concrete pavement The speed of construction prevents the benefits of large slipform machinery from being fully utilized. On the other hand, the construction quality and overall flatness of the bridge and culvert pavement on the expressway are reduced.

   Objectively, highways, regardless of the cement concrete pavement and reinforced concrete bridge deck, must use curbstone slipform to talk about the pavement mechanized pavement construction technology to ensure its construction quality. Otherwise, the manual construction method will continue to be used. Under such a strong destructive force on the highway, the bridge deck pavement layer cannot be resisted, and serious damage may occur 3 to 5 years after opening to traffic. Currently, rigid bridge deck pavement Repair of the coating is quite difficult.