| With the rapid development of the national economy, road transport and loading of motor vehicles is also growing rapidly, reports on the highway suffers the breakage and restrictions on vehicle load also increase gradually, Road traffic tolerance has become the bottleneck of economic development. In order to alleviate this situation, the state has increased its investment in highway construction, From highway construction in 2005 of 1.92×106km extended to 2010 2.30×106km, and 2.74×106km of targets, the highway from the 2005 expansion of 4.1×104km to 2010 6.50×104km, this effectively promoted the development of the cause of road traffic.In recent years, highways develop quickly, and the cement concrete road faces the structure form from 90's in 20 centuries be fly to develop soon in highway constuct, the mileage also increases very quickly, close the end of 2002, our country have already set up the cement concrete highway amounts to more than 130,000 kms.At the our country, the cement concrete superhighway has the resources advantage of the with abundant resources, it constuct the opportunity that the lieutenant general faces the high-speed development in the future economy, also providing the good opportunity for the development of the road cement.With the role of transport infrastructure in the load increasing, the United States has 30 percent domestic highway and built a cement concrete pavement; Quebec, Canada Cement Concrete Highway in Canada about 4%. In Europe, Belgium is the use of cement concrete road surface than any other country, about 50% of the highway is of cement concrete pavement, the vast majority of the use of cement concrete pavement to meet the design requirements for the status quo. Cement Concrete Paving with the old road is also commonly used in Belgium, especially the German cement concrete pavement is excellent to show the long-term performance.High-grade highways in China, the cement concrete pavement (Highway and Highway 1) about 25%, the proportion of the secondary following the road around 40%. As a result of modern road traffic and the traffic load further increases, to further enhance the degree of drainage, asphalt concrete pavement will be facing a severe test, much of asphalt concrete pavement was opened to traffic shortly after the short period of several months, has long 3 ~ 4 years, however, there rutting, cracking and other damage, the need for large-scale maintenance or Overlay not only affects the transport, but also caused great economic losses.Cement concrete pavement and asphalt pavement is the main difference between the rigid structure of the former and the latter is a flexible structure, and the flexible structure of roads and road-rigid structure of the nature of their difference is the distribution of load in different ways. Concrete has the characteristics of rigid and hard, rigid load distribution of the road to a level below a wide range of areas, roads, much of the structure of the bearing capacity of concrete provided; flexible pavement is a soft material, can not be similar to concrete like to load separate, flexible road usually need more levels and a greater thickness to the load transfer to the level below.Cement concrete pavement with a good overall performance of the road, the road high strength, long life cycle, lower maintenance costs later, can make use of local resources, promote the benefits of local economic development; At the same time when there is traffic noise, road damage long after the restoration, repair difficulties shortcomings. Cement concrete pavement for vehicular traffic, and axle load, and drainage and high traffic areas, especially in areas with heavy traffic, high-grade highways.China is still a developing country, economic underdevelopment, uneven regional development, infrastructure building is still a certain gap between the developed countries, especially in transport infrastructure, in the current circumstances, the development of transport infrastructure should be selected low cost and good performance, compared with China's national conditions of road construction methods.Asphalt as a result of China's limited resources, with high wax for heavy road transport rely heavily on import of petroleum asphalt, asphalt concrete pavement and therefore relatively high cost. Compared with the asphalt, our resources and the supply of cement very abundant, the need of imports, according to statistics, China's existing cement output reached more than 1000 million t, and cement concrete highway is one of the most famous of the advantages of its excellent durability and greater capacity, more suitable for China's national conditions.In the asphalt road, would have a serious re-load the track at the same time, heavy vehicles will have to start braking and wavy surface, in the intersection or corner so easy to have a soft displacement of asphalt material to form a ripple, there rut. Characteristics of the rigid concrete pavement may prevent this form of deformation, rutting will not occur, corrugated-like surface and displacement.In humid weather, asphalt track will be on the road to water and to increase the possibility of sliding; In winter, the asphalt track in the water will become ice, an increase of the possibility of traffic accidents. Taking into account the driver, as well as the personal safety of passengers, cement concrete roads with a more obvious role in anti-skid, which is due to its containing two types of macro-and micro-structure. Macro-structure mainly refers to nap or groove through the construction process of the trench structure, the micro-structure mainly refers to the role through the nap or abrasion in the mortar of fine surface structureCement concrete road at night can significantly improve the visibility, Cement Concrete Pavement Asphalt Pavement than brighter colors, better reflection from the cars and light street lamps. Because the reflection of reason, than that of cement concrete highway asphalt concrete per kilometer highway is less need for lighting.Heavy vehicles on roads in the flexible than when the road in the rigid moving greater tilt, tilt absorbed part of the car to move forward should be to promote energy, that is to say in the soft roads will need more energy and fuel , the rigid design of cement concrete to reduce the car's tilt and corresponding to the vehicle fuel consumption. National Research Council of Canada and Cement Association of Canada and conducted a two-year study, that the concrete trucks on roads than in the asphalt road on average 11 percent savings in fuel.China's limited resources and the quality of asphalt low asphalt used in highway construction rely heavily on imports, while China's resource-rich cement concrete, cement concrete highway construction has an advantage. Asphalt Pavement Rutting and thereby prone to stagnant water, increasing the possibility of sliding; cement concrete pavement construction and the use of the macro to the micro-structure of anti-skid, reduce vehicle braking distance to increase safety, and the rigidity of cement concrete pavement will not make the road Rut there, corrugated-like surface and displacement. Cement Concrete Pavement Asphalt Pavement than for brighter colors, can better reflection from the cars and street lighting, reducing lighting,Save energy and fuel; reinforced concrete and steel fiber reinforced concrete road surface is a new concrete road surface, has good prospects for development. Highway use of cement concrete pavement, whether in technical, economic, resources, and social development have a great advantage, cement concrete pavement in the highway construction will have a lot of room for the development of China's economic development will also play a an important contribution, as well as the development of the cement road provide a favorable environment for opportunities.In this paper, the main concrete structure on the formation and the basic performance, an analysis of the characteristics of cement concrete pavement and damaged the reasons for road concrete mix design, and focus on concrete all the way the relationship between performance indicators and concrete the impact of the road. Its main conclusions were as follows:1. With the gradually increasing water-cement ratio, the path of the bending strength of concrete, block compressive strength, splitting intensity gradually decreased.;2. With the gradually increasing water-cement ratio, the slump of cement concrete roads is gradually increasing. The same water-cement ratio, with the urgency to reduce the ratio of plasma, the slump of cement concrete roads is gradually increasing.3. The same water-cement ratio, with the urgency of reducing the plasma than the road of the flexural strength of cement concrete, block compressive strength gradually decreased, splitting intensity changes are not obvious.;4. The same water-cement ratio, if the same amount of air-entraining water-reducing agent, so as to reduce the ratio of plasma sets, the density of cement concrete road decreases;5. Air-entraining agent will not only reduce the unit water consumption of cement concrete to increase the workability of concrete, but also effectively improve the concrete and the isolation of the bleeding.6. Water-cement ratio cement slurry that is the consistency of decisions, small water-cement ratio, the more viscous cement, concrete mixing less movement of materials, when the water-cement ratio than an hour, then it is very difficult compacting concrete shape, the larger water-cement ratio , then a more dilute slurry, concrete mixture increases the mobility, but the cohesion and the ensuing deterioration of water-holding capacity. Water-cement ratio is too large, then there will be cement concrete segregation, the phenomenon of bleeding. |
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