The normal use and safety performance of road surface are largely affected by the serious impact of cement concrete pavement diseases on rural roads, and analyzing the causes of various pavement diseases and finding the corresponding solution measures have become one of the hot issues of more concern in the engineering community. For different kinds of hazards, to find the corresponding solutions, can be timely and effective treatment of disease, for engineering construction is very meaningful.
1 Crack of broken slab and road panel
1.1 Causes
1.1.1 Cracks appear on the road panel and the cement concrete panel slab bottom debonding is necessarily related. In the construction process of China’s rural roads, usually is not the asphalt intermediate layer laid in the cement pavement structure in the panel. After the seepage of water in the joints, because of the pumping effect of the wheels of traffic can easily lead to the phenomenon of debonding of the cement-stabilized gravel base and the bottom of the cement concrete panel, which will also increase the bending and tensile stresses that the cement concrete panel has to bear, thus accelerating the aging degree of the pavement.
1.1.2 No matching reinforcement in the panel. In some remote places in China, in the process of construction of rural roads, in order to save money, the construction process of cement pavement usually uses plain concrete panels that will not be paired with reinforcement within the panels, and this kind of panels are very easy to crack because of too much load and the factor of temperature fatigue, while the broken panels will also be This type of panel is prone to cracking due to excessive load and temperature fatigue, and the broken slab is also damaged.
1.2 Solution measures
1.2.1 Cracking can cause a single concrete panel to split into 3 or more unconnected pieces. mesh.
1.2.2 We can choose to use modified emulsified asphalt for grouting treatment, which can solve some small cracks in the surface layer of cement concrete slab. cracks.
1.2.3 If there are cracks on the surface of the panel, we can find a 10cm area on the surface of the panel, chisel it out, add Φ6 (Φ8) reinforcing mesh and fill it with new concrete to cover it.
2 The surface layer of the road is broken
2.1 Causes
If poor quality raw materials are selected, or if the concrete is not proportionally matched, or if the construction quality is inadequate, it is likely that the surface damage (e.g. spalling, cracking) will occur on the cement concrete panels of rural roads. Especially in this case, if there are more heavy-duty vehicles or more severe weather conditions, but also increase the degree of damage and damage to the panel.
2.2 Solution measures
Compared with the cement concrete panel with a wide range of damage to the road surface, the cement concrete slab with a lighter degree of damage can be chiseled away 3-5cm cement slab in the damaged area and then a layer of asphalt can be laid on the surface. For cement concrete slabs with more severe damage, 6 to 10 cm of cement slabs can be cut away and maintained with cement concrete of a higher strength level than the pavement. Repair.
3 Panel joints damage
3.1 Causes
Improperly spaced expansion joints or substandard joints can lead to damage to the interconnected cement concrete panel joints. There is such a phenomenon, in the construction process, there are a few units blindly pursuing flatness, thus making the number of expansion joints set to reduce, in the temperature gradient is large, the cement panel will shrink and expand, the first damage will occur in the more vulnerable link joints. If the transmission rod or tie bar at the joint is not set up in accordance with the standard, it will lead to misalignment due to the load, and if it is not repaired in time, then panel fracture or joint material breakage will occur near the joint.
3.2 Solution measures
We must set up expansion joints strictly according to the required documents or standard requirements, and add expansion joints when the spacing of expansion joints does not meet the requirements. If there is a small misstep at the joints, we can use a thin layer of asphalt table to level; if there is a serious misstep at the joints or the interconnected panels have been cracked, then we have to partially clean up the existing panels in a wide range, wait until after the proper setting of the transmission rod, and then lay a new concrete surface layer on the surface.
4 Sinkage of table back
4.1 Causes
The construction process of rural roads, but also inevitably encounter the situation of the bridge, there are two factors will lead to the back of the platform fill the overall tilt of the panel or the bridge head lap, one is the selection of inappropriate materials, and in the construction process is not in accordance with the standard to compact the material. If the bridge head expansion joint waterproofing effect is not good, downward penetration of water will also erode the soil base or grass-roots level, and in another degree greatly deepen the degree of slope of the back of the table road panel.
4.2 Solution measures
When it comes to the tilt of the cement concrete slab at the back of the bridge sink, there are two solutions: (1) to ensure that the work of the waterproofing function of the expansion joint is done to reduce the content of water infiltration; (2) filler such as slurry stone in the sinkage gap at the back of the table, in the place where the settlement of the lap plate tilt is serious, use asphalt mixture to level or redo the lap.
5 Uneven settlement of road panel
5.1 Causes
Road panel has the phenomenon of uneven settlement and roadbed compaction condition and grass-roots strength uniformity is inextricably linked. If the compaction does not reach sufficient standards, then the roadbed will be deformed inconsistently under the action of the car load, and then it will make the cement concrete slab bottom voids; likewise, the grass-roots strength is not uniform is also an important factor affecting the bottom of the road panel voids. The voids promote the degree of plate bottom dehollowing under the coupling action of water and load, which leads to serious uneven settlement of the pavement.
5.2 Solution measures
For the uneven settlement of the road panel this phenomenon, we should field survey, to determine a good match with the actual repair program, the right remedy. If the strength of the grass-roots level is still lacking, we can take local replacement to fill the way to repair, and at the same time to improve the ability of the pavement to resist water damage, you can choose to sprinkle emulsified asphalt sealer on the contact surface of the grass-roots level and surface layer. Also, if the soil base compaction is detected to be small, it can be locally grouted as a way to stabilize the soil base and minimize the amount of soil base settlement later.
In short, the causes of rural highway cement concrete pavement disease is multifaceted, may be improper use of roadbed filling materials lead to the sinking or collapse of the roadbed, but also because the soft base is not properly handled, there are also because the backfill of the structure platform back does not meet the standards should be met and other reasons, these will make the service life of the road shortened, the vehicle driving comfort reduced. Thus, it can be seen that the analysis of cement concrete pavement hazards on rural roads is very beneficial and necessary. For the pavement hazards, we should always keep alert and follow the purpose of “prevention-oriented, prevention and control combined”. Once the seeds of pavement hazards are found, we should deal with them as soon as possible to stop the spread and deepening of the disease.